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Ko te hanga hiko o te waikawa adipic (he matū mua o te nairona 66) mai i te hinu CA (he ranunga o te cyclohexanone me te cyclohexanol) he rautaki pumau ka taea te whakakapi i ngā tikanga tuku iho e hiahia ana ki ngā āhuatanga uaua. Heoi, ko te iti o te kiato o te iahiko me ngā tauhohenga whanaketanga hāora e whakataetae ana ka whakawhāiti nui i ana tono ahumahi. I roto i tēnei mahi, ka whakarerekēhia e mātou te nickel double hydroxide me te vanadium hei whakarei ake i te kiato o te iahiko me te pupuri i te pai o te faradaic teitei (>80%) i runga i te whānuitanga o te pūmanawa (1.5–1.9 V vs. te hiko hauwai hurihuri). I whakaatuhia e ngā rangahau whakamātautau me ngā rangahau ariā e rua ngā tūranga matua o te whakarerekētanga V, tae atu ki te hanga anō whakateretere me te whakapai ake i te adsorption cyclohexanone. Hei tohu o te ariā, i hangaia e mātou he huihuinga membrane-electrode i whakaputa i te waikawa adipic me te pai o te faradaic teitei (82%) me te hua (1536 μmol cm-2 h-1) i te kiato o te iahiko e tika ana mō te ahumahi (300 mA cm-2), me te whakatutuki i te pumau >50 h. E whakaatu ana tēnei mahi i tētahi whakateretere whai hua mō te hanga hiko o te waikawa adipic me te hua teitei me te pūmanawa ahumahi.
Ko te waikawa adipic (AA) tētahi o ngā waikawa dicarboxylic aliphatic tino nui, ā, e whakamahia ana i roto i te hanga nairona 66 me ētahi atu polyamides, polymers rānei1. I roto i te ahumahi, ka hangaia te AA mā te whakahāngai i te ranunga o te cyclohexanol me te cyclohexanone (arā, te hinu AA) mā te whakamahi i te waikawa hauota 50–60 vol% hei kaiwhakahāngai. He āwangawanga taiao tēnei tukanga e pā ana ki te tukunga o te waikawa hauota kukū me ngā waikura hauota (N2O me NOx) hei hau kati kōtuhi2,3. Ahakoa ka taea te whakamahi i te H2O2 hei kaiwhakahāngai matomato rerekē, ko te utu nui me ngā āhuatanga hanga uaua ka uaua te whakamahi i roto i te mahi, ā, me whai tikanga whai hua ake, pumau hoki4,5,6.
I roto i te tekau tau kua pahure ake nei, kua nui haere te aro o ngā kaipūtaiao ki ngā tikanga matū hiko me te hanga wahie nā te mea he pai ki a rātou te whakamahi i te pūngao hou me te mahi i raro i ngā āhuatanga ngawari (hei tauira, te pāmahana rūma me te pēhanga taiao)7,8,9,10. I roto i tēnei whakaaro, he mea tino nui te whanaketanga o te hurihanga hiko o te hinu KA ki te AA kia whiwhi ai i ngā painga o runga ake nei, me te whakakore hoki i te whakamahinga o te waikawa hauota me ngā tukunga hauota e kitea ana i roto i te hanga tikanga (Pikitia 1a). I mahia e Petrosyan et al. te mahi matua, nāna i kōrero ko te tauhohenga waikura hiko o te cyclohexanone (COR; cyclohexanone, cyclohexanol rānei kua rangahauhia hei tohu hinu KA) i runga i te nickel oxyhydroxide (NiOOH), engari i whiwhihia he iti te kiato o te iahiko (6 mA cm-2) me te hua AA ngawari (52%)11,12. Mai i taua wā, kua nui te ahunga whakamua i roto i te whanaketanga o ngā whakakorikori e hangai ana ki te nickel hei whakarei ake i te mahi COR. Hei tauira, i hangaia he whakakorikori nikara hauwai (Cu-Ni(OH)2) kua tāpirihia ki te parahi hei whakatairanga i te wehenga Cα–Cβ i roto i te cyclohexanol13. Nō nā tata nei mātou i pūrongo ai mō tētahi whakakorikori Ni(OH)2 kua whakarerekētia ki te konutai dodecyl sulfonate (SDS) hei waihanga i tētahi taiao moroiti hydrophobic e whakarei ake ana i te cyclohexanone14.
a Ngā wero o te whakaputanga AA mā te whakahāora hiko o te hinu KA. b Te whakataurite i te COR whakakorikori hiko o ngā whakakorikori Ni-pūtake kua pūrongohia i mua me tā mātou whakakorikori i roto i te pūnaha irahiko-toru me te pūnaha pākahiko rere11,13,14,16,26. Kei roto i ngā Ripanga Tāpiri 1 me te 2 ngā mōhiohio taipitopito mō ngā tawhā tauhohenga me te mahi tauhohenga. c Te mahi whakakorikori o ā mātou whakakorikori NiV-LDH-NS mō te COR i roto i te tauhohenga pūtau-H me te MEA, e mahi ana i runga i te whānuitanga o te pūmanawa.
Ahakoa i whakapai ake ngā tikanga i runga ake nei i te mahi COR, i whakaatuhia e ngā whakakorikori Ni-based kua whakaahuatia te pai o te AA Faraday (FE) teitei (>80%) i ngā pūmanawa iti noa iho, i raro iho i te 1.6 V ki te whakataurite ki te hiko hauwai hurihuri (RHE, whakarāpopototia VRHE). Nō reira, ko te kiato iahiko wāhanga kua pūrongohia (arā, ko te kiato iahiko katoa kua whakareatia ki te FE) o te AA kei raro tonu i te 60 mA cm−2 (Pikitia 1b me te Ripanga Tāpiri 1). Ko te kiato iahiko iti kei raro rawa atu i ngā whakaritenga ahumahi (>200 mA cm−2)15, e whakararuraru nui ana i te hangarau electrocatalytic mō te hanga AA tere-rahi (Pikitia 1a; runga). Hei whakanui ake i te kiato iahiko, ka taea te whakamahi i tētahi pūmanawa pai ake (mō te pūnaha hiko-toru) he ngaohiko pūtau teitei ake rānei (mō te pūnaha hiko-rua), he huarahi māmā tēnei mō ngā huringa electrocatalytic maha, inā koa te tauhohenga whanaketanga hāora (OER). Heoi, mō te COR i ngā pūmanawa anodic teitei, ka taea e te OER te noho hei kaiwhakataetae nui ki te whakaiti i te FE o te AA, ā, ka whakaiti i te whai huatanga o te pūngao (Pikitia 1a; raro). Hei tauira, i te arotake i te ahunga whakamua o mua (Pikitia 1b me te Ripanga Tāpiri 1), i pouri mātou i te kitenga kua heke te FE o te AA i runga i te Ni(OH)2 kua whakarerekētia e te SDS mai i te 93% ki te 76% me te whakanui ake i te pūmanawa kua whakamahia mai i te 1.5 VRHE ki te 1.7 VRHE14, i te mea kua heke te FE o te AA i runga i te CuxNi1-x(OH)2/CF mai i te 93% ki te 69% me te whakanui ake i te pūmanawa mai i te 1.52 VRHE ki te 1.62 VRHE16. Nō reira, ko te kiato iahiko wāhanga kua pūrongohia o te AA kāore e piki ake i te taha ōrite i ngā pūmanawa teitei ake, e whakawhāiti ana i te whakapainga o te mahi a te AA, me te kore e whakahua i te nui o te whakapaunga pūngao nā te iti o te FE o te AA. Haunga ngā whakakorikori e hangai ana ki te nikara, kua whakaatuhia hoki e ngā whakakorikori e hangai ana ki te cobalt te mahi whakakorikori i roto i te COR17,18,19. Heoi, ka heke te pai o te mahi i ngā pūmanawa teitei ake, ā, ki te whakaritea ki ngā whakakorikori e hangai ana ki te Ni, he nui ake ngā herenga pūmanawa i roto i ngā tono ahumahi, pērā i te pikinga ake o ngā utu me te iti ake o ngā taonga. Nō reira, he mea hiahia kia whakawhanakehia ngā whakakorikori e hangai ana ki te Ni me te kiato iahiko teitei me te FE i roto i te COR kia whai hua ai te whakatutuki i ngā hua AA teitei.
I roto i tēnei mahi, ka pūrongo mātou i ngā nanosheets hauwai rua paparanga nikara kua whakarerekētia ki te vanadium(V) (NiV-LDH-NS) hei electrocatalysts whai hua mō te hanga AA mā te COR, e mahi ana i runga i te whānuitanga pūmanawa whānui me te OER kua pehia nui, e tutuki ai te FE teitei me te kiato iahiko i roto i ngā pūtau-H me ngā huihuinga electrode membrane (MEAs; Pikitia 1 b). Ka whakaaturia tuatahitia e mātou ko te whai huatanga o te waikura acetylene i runga i te Ni(OH)2 nanosheet catalyst (Ni(OH)2-NS) noa ka heke, e ai ki te tumanako, i ngā pūmanawa teitei ake, mai i te 80% i te 1.5 VRHE ki te 42% i te 1.9 VRHE. He rerekē rawa atu, i muri i te whakarerekētanga o te Ni(OH)2 me te V, i whakaatuhia e te NiV-LDH-NS te kiato iahiko teitei ake i te pūmanawa kua hoatu, ā, ko te mea nui ake, i pupuri i te FE teitei i runga i te whānuitanga pūmanawa whānui. Hei tauira, i te 1.9 VRHE, i whakaatuhia he kiato iahiko o te 170 mA cm−2 me te FE o te 83%, he pai ake te whakakorikori mō te COR i roto i te pūnaha irahiko-toru (Pikitia 1c me te Ripanga Tāpiri 1). E whakaatu ana ngā raraunga whakamātautau me ngā raraunga ariā ko te whakarerekētanga V e whakatairanga ana i te nekehanga whakaiti mai i te Ni(OH)2 ki ngā Ni oxyhydroxides tino-valent (Ni3+xOOH1-x), e mahi ana hei wāhanga hohe mō te COR. I tua atu, i whakarei ake te whakarerekētanga V i te mimiti o te cyclohexanone i runga i te mata whakakorikori, he mea nui ki te pehi i te OER i ngā pūmanawa anodic teitei. Hei whakaatu i te pūmanawa o te NiV-LDH-NS i roto i tētahi horopaki pono ake, i hangaia e mātou he tauhohenga rere MEA, ā, i whakaatuhia he FE o te AA (82%) i te kiato iahiko e tika ana mō te ahumahi (300 mA cm−2), he nui ake i ā mātou hua o mua i roto i te tauhohenga rere membrane (Pikitia 1b me te Ripanga Tāpiri 2). Ko te hua e rite ana o te AA (1536 μmol cm−2 h−1) he nui ake i tērā i whiwhihia mā te whakamahi i te tukanga whakakorikori wera (<30 mmol gcatalyst−1 h−1)4. I tua atu, i whakaatu te whakakorikori i te pumau pai i te whakamahi i te MEA, me te pupuri i te FE >80% AA mō te 60 hāora i te 200 mA cm−2 me te FE >70% AA mō te 58 hāora i te 300 mA cm−2. Hei whakamutunga, i whakaatuhia e tētahi rangahau whaihua tuatahi (FEA) te whai huatanga utu o te rautaki whakakorikori hiko mō te hanga AA.
E ai ki ngā tuhinga o mua, ko te Ni(OH)2 he whakakorikori noa e whakaatu ana i te mahi pai mō te COR, nō reira i hangaia ai te Ni(OH)2-NS13,14 mō te wā tuatahi mā te tikanga whakakotahi-whakapūngao. I whakaatuhia e ngā tauira te hanganga β-Ni(OH)2, i whakaūtia e te X-ray diffraction (XRD; Pikitia 2a), ā, i kitea ngā nanosheets tino-angiangi (matotoru: 2–3 nm, rahi taha: 20–50 nm) mā te karu hiko tuku-taumira teitei (HRTEM; Pikitia Tāpiri 1) me ngā inenga karu hiko kaha atomika (AFM) (Pikitia Tāpiri 2). I kitea anō te whakakotahitanga o ngā nanosheets nā te mea he tino-angiangi.
a Ngā tauira whakarara hihi-X o Ni(OH)2-NS me NiV-LDH-NS. Ko te FE, te putanga, me te kiato iahiko AA i runga i te b Ni(OH)2-NS me te c NiV-LDH-NS i ngā pūmanawa rerekē. Ko ngā pae hapa e tohu ana i te paerewa rerekētanga o ngā inenga motuhake e toru e whakamahi ana i te whakakorikori kotahi. d Whakaahua HRTEM o NV-LDH-NS. Pae tauine: 20 nm. Whakaahua HAADF-STEM o NiV-LDH-NS me te mahere huānga e rite ana e whakaatu ana i te tohatoha o Ni (kakariki), V (kōwhai), me O (kikorangi). Pae tauine: 100 nm. f Ni 2p3/2, g O 1 s, me h V 2p3/2 raraunga XPS o Ni(OH)2-NS (runga) me NiV-LDH-NS (raro). Ko i FE me j ngā mahi AA i runga i ngā whakakorikori e rua i roto i ngā huringa 7. Ko ngā pae hapa e tohu ana i te paerewa rerekētanga o ngā inenga motuhake e toru e whakamahi ana i te whakakorikori kotahi, ā, kei roto i te 10%. Kei roto i ngā kōnae raraunga mata ngā raraunga mata mō a–c me f–j.
Kātahi ka arotakehia e mātou te pānga o te Ni(OH)2-NS ki te COR. Mā te whakamahi i te hikohiko pūmau, i whiwhi mātou i te 80% FE o te AA i te pūmau iti (1.5 VRHE) me te kore OER (Pikitia 2b), e tohu ana he pai ake te kaha o te COR i te OER i ngā pūmau anodic iti. I kitea ko te hua matua ko te waikawa glutaric (GA) me te FE o te 3%. I inehia hoki te aroaro o ngā rahinga iti o te waikawa succinic (SA), te waikawa malonic (MA), me te waikawa oxalic (OA) e te HPLC (tirohia te Pikitia Tāpiri 3 mō te tohatoha hua). Kāore i kitea he waikawa formic i roto i te hua, e kī ana ka hangaia pea he warowaihā hei hua taha C1. Hei whakamātautau i tēnei whakapae, i waikawahia te irahiko mai i te hikohiko katoa o te 0.4 M cyclohexanone, ā, i tukuna ngā hua hau mā roto i te otinga Ca(OH)2. Nō reira, ka pōuri te otinga, e whakaū ana i te hanganga o te warowaihā i muri i te hikohiko. Heoi, nā te iti o te hiko katoa i puta i te tukanga hikohiko (Pikitia 2b, c), he iti te kukū o te warowaihā, ā, he uaua ki te ine. Hei tāpiri, tera pea ka puta mai ētahi atu hua C2-C5, engari kāore e taea te ine i ō rātou rahinga. Ahakoa he uaua ki te ine i te tapeke o ngā hua, e 90% o te tapeke o te taurite hikohiko e tohu ana kua tautuhia te nuinga o ngā tukanga hikohiko, e whakarato ana i te pūtake mō tō tātou māramatanga tikanga. Nā te iti o te kiato o te iahiko (20 mA cm−2), ko te hua o te AA he 97 μmol cm−2 h−1 (Pikitia 2b), he ōrite ki te 19 mmol h−1 g−1 i runga i te kawenga papatipu o te whakakorikori (5 mg cm−2), he iti iho i te hua whakakorikori wera (~30 mmol h−1 g−1)1. I te pikinga o te pūmanawa i whakamahia mai i te 1.5 ki te 1.9 VRHE, ahakoa i piki ake te kiato o ia au whānui (mai i te 20 ki te 114 mA cm−2), i te wā kotahi ka heke nui te AA FE, mai i te 80% ki te 42%. Ko te hekenga o te FE i ngā pūmanawa pai ake te take nui o te whakataetae mō te OER. Ina koa i te 1.7 VRHE, ka arahi te whakataetae OER ki te hekenga nui o te AA FE, ā, ka whakaitihia te mahi a te AA me te pikinga o te kiato o ia au whānui. Nō reira, ahakoa i piki ake te kiato o ia au wāhanga o te AA mai i te 16 ki te 48 mA cm−2 me te pikinga o te hua o te AA (mai i te 97 ki te 298 μmol cm−2 h−1), he nui te pūngao tāpiri i pau (2.5 W h gAA−1 atu mai i te 1.5 ki te 1.9 VRHE), ka hua ake he pikinga o ngā tukunga waro o te 2.7 g CO2 gAA−1 (kei roto i te Tuhipoka Tāpiri 1 ngā taipitopito tatau). Ko te OER i kīia i mua hei whakataetae ki te tauhohenga COR i ngā pūmanawa anodic teitei, he rite ki ngā pūrongo o mua, ā, he wero whānui mō te whakapai ake i te hua o te AA14,17.
Hei whakawhanake i tētahi whakakorikori COR e ahu mai ana i te Ni(OH)2-NS, i tātarihia tuatahitia e mātou te wāhanga hohe. I kitea e mātou ngā tihi i te 473 cm-1 me te 553 cm-1 i roto i ā mātou hua o te tirotiro Raman in situ (Pikitia Tāpiri 4), e rite ana ki te piko me te totoro o ngā here Ni3+-O i roto i te NiOOH. Kua tuhia ko te NiOOH te hua o te whakaiti Ni(OH)2 me te kohikohi Ni(OH)O i ngā pūmanawa anodic, ā, ko te wāhanga hohe tonu i roto i te whakakōkī hiko20,21. Nō reira, e tumanako ana mātou mā te whakatere i te tukanga hanga anō wāhanga o te Ni(OH)2 ki te NiOOH ka taea te whakarei ake i te mahi whakakorikori o te COR.
I ngana mātou ki te whakarerekē i te Ni(OH)2 me ngā konganuku rerekē nā te mea i kitea ko te whakarerekētanga heteroatom ka whakatairanga i te hanga anō i te wāhanga i roto i ngā waikura/waikura konganuku whakawhiti22,23,24. I hangaia ngā tauira mā te whakatakotoranga tahi o te Ni me te tuarua o ngā matū whakarewa. I roto i ngā tauira rerekē kua whakarerekētia te konganuku, ko te tauira kua whakarerekētia te V (ōwehenga ngota V:Ni 1:8) (e kiia nei ko te NiV-LDH-NS) i whakaatu i te kiato iahiko teitei ake i roto i te COR (Pikitia Tāpiri 5) me te mea nui ake, ko te AA FE teitei i runga i te matapihi pūmanawa whānui. Ina koa, i te pūmanawa iti (1.5 VRHE), ko te kiato iahiko o te NiV-LDH-NS he 1.9 ngā wā teitei ake i tērā o te Ni(OH)2-NS (39 vs. 20 mA cm−2), ā, he rite te AA FE i runga i ngā whakakorikori e rua (83% vs. 80%). Nā te nui ake o te kiato o te iahiko me te FE AA rite tonu, ko te hua o te NiV-LDH-NS e 2.1 ngā wā teitei ake i tērā o te Ni(OH)2-NS (204 vs. 97 μmol cm−2 h−1), e whakaatu ana i te pānga whakatairanga o te whakarerekētanga V ki te kiato o te iahiko i ngā pūmanawa iti (Pikitia 2c).
I te pikinga ake o te pūmanawa kua whakamahia (hei tauira, 1.9 VRHE), ko te kiato o te iahiko i runga i te NiV-LDH-NS he 1.5 ngā wā teitei ake i tērā i runga i te Ni(OH)2-NS (170 vs. 114 mA cm−2), ā, he rite tonu te pikinga ki tērā i ngā pūmanawa iti iho (1.9 ngā wā teitei ake). He mea nui, i mau tonu te NiV-LDH-NS i te AA FE teitei (83%) ā, i tino pehia te OER (O2 FE 4%; Pikitia 2c), i pai ake i te Ni(OH)2-NS me ngā whakakorikori i pūrongohia i mua me te AA FE iti iho i ngā pūmanawa anodic teitei (Ripanga Tāpiri 1). Nā te nui o te FE o te AA i roto i te matapihi pūmanawa whānui (1.5–1.9 VRHE), i tutuki te tere whakaputa AA o te 867 μmol cm−2 h−1 (he rite ki te 174.3 mmol g−1 h−1) i te 1.9 VRHE, e whakaatu ana i te mahi pai i roto i ngā pūnaha electrocatalytic me te thermocatalytic i te wā i whakatauritea ai te ngohe e te utaina papatipu katoa o ngā tauira NiV-LDH-NS (Pikitia Tāpiri 6).
Hei mārama ki te kiato o te au teitei me te FE teitei i runga i te whānuitanga o te pūmanawa i muri i te whakarerekētanga o te Ni(OH)2 me te V, i whakaahuahia e mātou te hanganga o te NiV-LDH-NS. I whakaatuhia e ngā hua XRD ko te whakarerekētanga me te V i puta ai he whakawhiti wāhanga mai i te β-Ni(OH)2 ki te α-Ni(OH)2, ā, kāore i kitea he momo tioata e pā ana ki te V (Pikitia 2a). E whakaatu ana ngā hua HRTEM ko te NiV-LDH-NS te uri o ngā nanosheets Ni(OH)2-NS tino angiangi, ā, he rite ngā taha taha (Pikitia 2d). I whakaatuhia e ngā inenga AFM he kaha te kaha o te whakakotahitanga o ngā nanosheets, ka hua ake he matotoru ine tata ki te 7 nm (Pikitia Tāpiri 7), he nui ake i te Ni(OH)2-NS (matotoru: 2–3 nm). I whakaatuhia e te tātari mahere X-ray marara-pūngao (EDS) (Pikitia 2e) he pai te tohatoha o ngā huānga V me Ni i roto i ngā nanosheets. Hei whakamārama i te hanganga hiko o V me tōna pānga ki a Ni, i whakamahia e mātou te X-ray photoelectron spectroscopy (XPS) (Pikitia 2f–h). I whakaatuhia e Ni(OH)2-NS ngā tihi hurihuri-āmiomio āhuatanga o Ni2+ (tihi wahine i te 855.6 eV, tihi amiorangi i te 861.1 eV, Pikitia 2f)25. Ka taea te wehewehe i te whānuitanga O1s XPS o Ni(OH)2-NS kia toru ngā tihi, i roto i ēnei ko ngā tihi i te 529.9, 530.9 me te 532.8 eV e pā ana ki te hāora whatunga (OL), te rōpū hydroxyl (Ni-OH) me te hāora e piri ana ki ngā hapa mata (OAds), ia (Pikitia 2g)26,27,28,29. I muri i te whakarerekētanga ki a V, ka puta te tihi V 2p3/2, ka taea te wehewehe ki ngā tihi e toru kei te 517.1 eV (V5+), 516.6 eV (V4+) me te 515.8 eV (V3+), ia, e tohu ana ko ngā momo V i roto i te hanganga kei roto i ngā āhua waikura teitei (Pikitia 2h)25,30,31. Hei tāpiri, ko te tihi Ni 2p i te 855.4 eV i roto i te NiV-LDH-NS i nekehia kino (mā te 0.2 eV pea) ki te whakataurite ki tērā i roto i te Ni(OH)2-NS, e tohu ana i whakawhitihia ngā irahiko mai i V ki Ni. Ko te āhua valence iti o Ni i kitea i muri i te whakarerekētanga V he rite ki ngā hua o te Ni K-edge X-ray absorption near-edge spectroscopy (XANES) (tirohia te wāhanga "V Modification Promotes Catalyst Reduction" i raro nei mō ētahi atu taipitopito). I muri i te maimoatanga COR mō te 1 h, i tohua te NiV-LDH-POST hei NiV-LDH-POST, ā, i whakaahuatia katoatia mā te whakamahi i te karu hiko tuku, te mahere EDS, te diffraction hihi-X, te spectroscopy Raman, me ngā inenga XPS (Pikitia Tāpiri 8 me te 9). I noho tonu ngā whakakorikori hei tākai me te āhua nanosheet tino angiangi (Pikitia Tāpiri 8a–c). I heke te tioata o ngā tauira, ā, i heke te ihirangi V nā te tangohanga V me te hanga anō i te whakakorikori (Pikitia Tāpiri 8d–f). I whakaatuhia e ngā hihi XPS he hekenga i te kaha o te tihi V (Pikitia Tāpiri 9), i kīia nā te tangohanga V. Hei tāpiritanga, i whakaatuhia e te tātaritanga whānuitanga O 1s (Pikitia Tāpiri 9d) me ngā inenga irahiko paramagnetic (EPR) (Pikitia Tāpiri 10) te nui o ngā wāhi kore hāora i runga i te NiV-LDH-NS i piki ake i muri i te 1 hāora o te electrolysis, ka arahi pea tēnei ki tētahi nekehanga kino i roto i te pūngao here Ni 2p (tirohia ngā Pikitia Tāpiri 9 me te 10 mō ētahi atu taipitopito)26,27,32,33. Nō reira, he iti noa te huringa hanganga i whakaatuhia e te NiV-LDH-NS i muri i te 1 hāora o te COR.
Hei whakaū i te mahi nui a V ki te whakatairanga i te COR, i hangaia e mātou ngā whakakorikori NiV-LDH me ngā ōwehenga ngota V:Ni rerekē (1:32, 1:16, me te 1:4, kua tohua ko NiV-32, NiV-16, me NiV-4, ia) engari ko te 1:8 mā te tikanga taupū kotahi. E whakaatu ana ngā hua mahere EDS he tata te ōwehenga ngota V:Ni i roto i te whakakorikori ki tērā o te mua (Pikitia Tāpiri 11a–e). I te pikinga ake o te whakarerekētanga V, ka piki ake te kaha o te whānuitanga V 2p, ā, ka neke tonu te kaha here o te rohe Ni 2p ki te taha kino (Pikitia Tāpiri 12). I taua wā anō, ka piki haere te ōwehenga o te OL. E whakaatu ana ngā hua o te whakamātautau whakakorikori ka taea te pehi pai i te OER ahakoa he iti noa te whakarerekētanga V (ōwehenga ngota V:Ni o te 1:32), me te hekenga o te O2 FE mai i te 27% ki te 11% i te 1.8 VRHE i muri i te whakarerekētanga V (Pikitia Tāpiri 11f). I te pikinga ake o te ōwehenga V:Ni mai i te 1:32 ki te 1:8, ka piki ake te mahi whakateretere. Heoi, i te pikinga ake o te whakarerekētanga V (ōwehenga V:Ni o te 1:4), ka heke te mātotoru o te au, e whakapae ana mātou nā te hekenga o te mātotoru o ngā pae hohe Ni (ina koa ko te wāhanga hohe NiOOH; Pikitia Tāpiri 11f). Nā te pānga whakatairanga o te whakarerekētanga V me te tiakitanga o ngā pae hohe Ni, ko te whakateretere me te ōwehenga V:Ni o te 1:8 i whakaatu i te mahi FE me te AA teitei rawa atu i roto i te whakamātautau tirotiro ōwehenga V:Ni. Hei whakamārama mēnā kei te mau tonu te ōwehenga V:Ni i muri i te hikohiko, i tautuhia te hanganga o ngā whakateretere i whakamahia. E whakaatu ana ngā hua mō ngā whakateretere me ngā ōwehenga V:Ni tuatahi mai i te 1:16 ki te 1:4, ka heke te ōwehenga V:Ni ki te 1:22 i muri i te tauhohenga, tērā pea nā te rerenga o V nā te hanga anō o te whakateretere (Pikitia Tāpiri 13). Kia mōhio koe i kitea ngā AA FE rite tonu i te wā i rite, i teitei ake rānei te ōwehenga V:Ni tuatahi ki te 1:16 (Pikitia Tāpiri 11f), ka taea te whakamārama mā te hanga anō i te whakakōkī ka hua ake he ōwehenga V:Ni rite tonu i roto i ngā whakakōkī e whakaatu ana i te mahi whakakōkī rite tonu.
Hei whakaū anō i te hiranga o te Ni(OH)2 kua whakarerekētia ki te V hei whakarei ake i te mahi a te COR, i whakawhanakehia e mātou ētahi atu tikanga hanga e rua hei whakauru i te V ki roto i ngā rauemi Ni(OH)2-NS. Ko tētahi he tikanga whakaranu, ā, ko te tauira e kiia ana ko NiV-MIX; ko tētahi he tikanga whakapūtā raupapa, ā, ko te tauira e kiia ana ko NiV-SP. Kei roto i te wāhanga Tikanga ngā taipitopito o te hanga. I whakaatuhia e te mahere SEM-EDS kua angitu te whakarerekētanga o te V ki te mata Ni(OH)2-NS o ngā tauira e rua (Pikitia Tāpiri 14). E whakaatu ana ngā hua o te electrolysis i te 1.8 VRHE, ko te pai o te AA i runga i ngā irahiko NiV-MIX me NiV-SP he 78% me te 79%, ia, e whakaatu ana i te pai ake o te Ni(OH)2-NS (51%). I tua atu, i pehia te OER i runga i ngā irahiko NiV-MIX me NiV-SP (FE O2: 7% me te 2%, ia) ki te whakataurite ki te Ni(OH)2-NS (FE O2: 27%). E whakaū ana ēnei hua i te pānga pai o te whakarerekētanga V i roto i te Ni(OH)2 ki te pehitanga OER (Pikitia Tāpiri 14). Heoi, i whakararuhia te pumau o ngā whakakorikori, i kitea i te hekenga o te FE AA i runga i te NiV-MIX ki te 45% me te NiV-SP ki te 35% i muri i ngā huringa COR e whitu, e tohu ana i te hiahia ki te whakamahi i ngā tikanga tika hei whakapumau i ngā momo V, pērā i te whakarerekētanga V i roto i te whatunga Ni(OH)2 i roto i te NiV-LDH-NS, koinei te whakakorikori matua i roto i tēnei mahi.
I arotakehia hoki e mātou te pumau o te Ni(OH)2-NS me te NiV-LDH-NS mā te tuku i te COR ki ngā huringa maha. I whakahaerehia te tauhohenga mō te 1 hāora ia huringa, ā, i whakakapia te electrolyte i muri i ia huringa. I muri i te huringa tuawhitu, i heke te mahi a te FE me te AA i runga i te Ni(OH)2-NS mā te 50% me te 60%, ia, i te mea i kitea he pikinga o te OER (Pikitia 2i, j). I muri i ia huringa, i tātarihia e mātou ngā ānau voltammetry cyclic (CV) o ngā whakakorikori, ā, i kitea ko te tihi waikura o te Ni2+ i heke haere, e tohu ana i te hekenga o te kaha redox o te Ni (Pikitia Tāpiri 15a–c). I te taha o te pikinga o te kukū cation Ni i roto i te electrolyte i te wā o te electrolysis (Pikitia Tāpiri 15d), e kī ana mātou ko te whakahekenga mahi (te hekenga o te hua FE me te AA) ki te tangohanga o te Ni mai i te whakakorikori, ka hua ake he nui ake te whakaaturanga o te papa Ni pahuka e whakaatu ana i te mahi OER. I te rerekētanga, i whakaroahia e NiV-LDH-NS te hekenga o te hua FE me te AA ki te 10% (Pikitia 2i, j), e tohu ana ko te whakarerekētanga V i aukati i te tangohanga Ni (Pikitia Tāpiri 15d). Hei mārama ki te pumau ake o te whakarerekētanga V, i whakahaerehia e mātou ngā tātaitanga ariā. E ai ki ngā tuhinga o mua34,35, ka taea te whakamahi i te huringa enthalpy o te tukanga tangohanga whakarewa o ngā ngota whakarewa i runga i te mata hohe o te whakakorikori hei whakaahuatanga whaitake hei aromatawai i te pumau o te whakakorikori. Nō reira, i whakatauhia ngā huringa enthalpy o te tukanga tangohanga whakarewa o ngā ngota Ni i runga i te mata (100) o te Ni(OH)2-NS me te NiV-LDH-NS kua hangaia anō (NiOOH me NiVOOH, ia) (ko ngā taipitopito o te hanganga tauira e whakaahuatia ana i roto i te Tuhipoka Tāpiri 2 me te Pikitia Tāpiri 16). I whakaaturia te tukanga tangohanga whakarewa o Ni mai i te NiOOH me te NiVOOH (Pikitia Tāpiri 17). He nui ake te utu pūngao o te tango-whakarewa Ni i runga i te NiVOOH (0.0325 eV) i tērā i runga i te NiOOH (0.0005 eV), e tohu ana ko te whakarerekētanga V ka whakarei ake i te pumau o te NiOOH.
Hei whakaū i te pānga aukati OER ki te NiV-LDH-NS, inā koa i ngā pūmanawa anodic teitei, i whakahaerehia te ine ine papatipu hiko rerekē (DEMS) hei tirotiro i te hanganga O2 e whakawhirinaki ana ki te pūmanawa i runga i ngā tauira rerekē. I whakaatuhia e ngā hua i te korenga o te cyclohexanone, i puta te O2 i runga i te NiV-LDH-NS i te pūmanawa tīmatanga o te 1.53 VRHE, he iti iho i te O2 i runga i te Ni(OH)2-NS (1.62 VRHE) (Pikitia Tāpiri 18). E kī ana tēnei hua kāore pea te aukati OER o te NiV-LDH-NS i te wā o te COR i ahu mai i tōna ngohe OER iti, he rite ki te kiato iahiko teitei ake i roto i ngā ānau voltammetry ruku rārangi (LSV) i runga i te NiV-LDH-NS i tērā i runga i te Ni(OH)2-NS me te kore he cyclohexanone (Pikitia Tāpiri 19). I muri i te whakaurunga o te cyclohexanone, ko te whakaroa o te whanaketanga O2 (nā te painga thermodynamic pea o te COR) te whakamārama i te FE teitei o te AA i te rohe pūmanawa iti. Ko te mea nui ake, ko te pūmanawa tīmatanga OER i runga i te NiV-LDH-NS (1.73 VRHE) he roa ake i tērā i runga i te Ni(OH)2-NS (1.65 VRHE), he rite ki te FE teitei o te AA me te FE iti o te O2 i runga i te NiV-LDH-NS i ngā pūmanawa pai ake (Pikitia 2c).
Hei mārama ake i te pānga whakatairanga o te whakarerekētanga V, i tātarihia e mātou te tere o te tauhohenga OER me te COR ki runga i te Ni(OH)2-NS me te NiV-LDH-NS mā te ine i ō rātou pari Tafel. He mea tika kia mōhio ko te kiato o te iahiko i te rohe Tafel nā te waikura o te Ni2+ ki te Ni3+ i te wā o te whakamātautau LSV mai i te pūmanawa iti ki te pūmanawa teitei. Hei whakaiti i te pānga o te waikura Ni2+ ki te ine pari COR Tafel, i waikura tuatahi mātou i te whakakorikori i te 1.8 VRHE mō te 10 meneti, kātahi ka mahia ngā whakamātautau LSV i te aratau matawai whakamuri, arā, mai i te pūmanawa teitei ki te pūmanawa iti (Pikitia Tāpiri 20). I whakatikatikaina te pihi LSV taketake me te 100% iR utu hei whiwhi i te pari Tafel. I te korenga o te cyclohexanone, ko te pari Tafel o NiV-LDH-NS (41.6 mV dec−1) he iti iho i te Ni(OH)2-NS (65.5 mV dec−1), e tohu ana ka taea te whakarei ake i te kinetics OER mā te whakarerekētanga V (Pikitia Tāpiri 20c). I muri i te whakaurunga o te cyclohexanone, ko te pari Tafel o NiV-LDH-NS (37.3 mV dec−1) he iti iho i te Ni(OH)2-NS (127.4 mV dec−1), e tohu ana he mārama ake te pānga kinetic o te whakarerekētanga V ki te COR ki te OER (Pikitia Tāpiri 20d). E whakaatu ana ēnei hua ahakoa ka whakatairangahia e te whakarerekētanga V te OER ki tētahi taumata, ka tere ake te tere o te kinetics COR, ka hua ake he pikinga o te FE o AA.
Hei mārama ki te pānga whakatairanga o te whakarerekētanga V i runga ake nei ki te mahi a te FE me te AA, i arotahi mātou ki te rangahau tikanga. Kua whakaatuhia e ētahi pūrongo o mua ka taea e te whakarerekētanga heteroatom te whakaiti i te tioata o ngā whakakorikori me te whakanui ake i te horahanga mata hikohiko kaha (EAS), ā, ka piki ake te maha o ngā pae hohe, ā, ka whakapai ake i te mahi whakakorikori36,37. Hei tirotiro i tēnei mea pea, i whakahaerehia e mātou he inenga ECSA i mua atu me muri i te whakahohenga hikohiko, ā, i whakaatuhia e ngā hua he rite te ECSA o Ni(OH)2-NS me NiV-LDH-NS (Pikitia Tāpiri 21), me te kore e whakauru i te awe o te kiato pae hohe i muri i te whakarerekētanga V ki te whakarei ake i te whakakorikori.
E ai ki te mōhiotanga whānuitia, i roto i te whakahāngaitanga hiko o ngā waipiro, o ētahi atu matūriki nucleophilic rānei, ka ngaro tuatahi ngā irahiko me ngā porotona o te Ni(OH)2, kātahi ka whakaitihia ki te NiOOH mā roto i ngā hikohiko i tētahi pūmanawa anodic38,39,40,41. Kātahi ka mahi te NiOOH kua hangaia hei momo COR hohe tūturu hei tango i te hauwai me ngā irahiko mai i te matūriki nucleophilic mā roto i ngā hikohiko matū hei hanga i te hua whakahāngaitanga20,41. Heoi, kua pūrongohia tata nei ahakoa ko te whakaiti ki te NiOOH ka mahi pea hei hikohiko whakatau tere (RDS) mō te whakahāngaitanga hiko o te waipiro ki runga i te Ni(OH)2, e ai ki ngā tuhinga hou, ko te whakahāngaitanga o ngā waipiro Ni3+ he tukanga tūpono pea mā roto i te whakawhiti irahiko kore-redox mā roto i ngā orbital kore noho o te Ni3+41,42. I whakaaweawehia e te rangahau tikanga i whakaputaina i roto i taua tuhinga anō, i whakamahia e mātou te dimethylglyoxime disodium salt octahydrate (C4H6N2Na2O2 8H2O) hei ngota tirotiro hei hopu i tētahi hanganga Ni2+ i puta mai i te whakaiti Ni3+ i te wā o te COR (Pikitia Tāpiri 22 me te Tuhipoka Tāpiri 3). I whakaatuhia e ngā hua te hanganga o te Ni2+, e whakaū ana i te wā kotahi o te whakaiti matū o te NiOOH me te electrooxidation o te Ni(OH)2 i te wā kotahi i te wā o te tukanga COR. Nō reira, ko te mahi catalytic ka whakawhirinaki pea ki te kinetics o te whakaiti Ni(OH)2 ki te NiOOH. I runga i tēnei mātāpono, i tirotirohia e mātou i muri mai mēnā ka tere ake te whakaiti o te Ni(OH)2 mā te whakarerekētanga o te V, ā, ka whakapai ake i te COR.
I whakamahia tuatahitia e mātou ngā tikanga Raman in situ hei whakaatu ko NiOOH te wāhanga hohe mō te COR i runga i te Ni(OH)2-NS me te NiV-LDH-NS mā te tirotiro i te hanganga o te NiOOH i ngā pūmanawa pai me tōna whakamahinga i muri mai i te whakaurunga o te cyclohexanone, whai muri i te tukanga "matū-hikohiko" kua whakahuatia ake nei (Pikitia 3a). I tua atu, ko te tauhohenga o te NiV-LDH-NS kua hangaia anō i nui ake i te Ni(OH)2-NS, e whakaatuhia ana e te ngaronga tere o te tohu Ni3+–O Raman. I muri mai ka whakaaturia e mātou he iti ake te pūmanawa pai o te NiV-LDH-NS mō te hanganga NiOOH ki te Ni(OH)2-NS i te aroaro, i te ngaro rānei o te cyclohexanone (Pikitia 3b, c me te Pikitia Tāpiri 4c, d). He mea nui, ko te mahi OER pai ake o te NiV-LDH-NS ka hua ake he nui ake ngā mirumiru e piri ana ki te arotahi o mua o te whāinga ine Raman, ka ngaro ai te tihi Raman i te 1.55 VRHE (Pikitia Tāpiri 4d). E ai ki ngā hua o te DEMS (Pikitia Tāpiri 18), ko te kiato o ia au i ngā pūmanawa iti (VRHE < 1.58 mō te Ni(OH)2-NS me te VRHE < 1.53 mō te NiV-LDH-NS) te take matua o te hanganga anō o ngā iona Ni2+ kaua ki te OER i te korenga o te cyclohexanone. Nō reira, he kaha ake te tihi waikura o te Ni2+ i te pihi LSV i tērā o te NiV-LDH-NS, e tohu ana ko te whakarerekētanga V ka whakanui ake i te kaha hanga anō ki a NiV-LDH-NS (tirohia te Pikitia Tāpiri 19 mō te tātari taipitopito).
a Ngā irahiko Raman in situ o Ni(OH)2-NS (maui) me NiV-LDH-NS (matau) i raro i ngā āhuatanga OCP i muri i te preoxidation i te 1.5 VRHE i roto i te 0.5 M KOH me te 0.4 M cyclohexanone mō te 60 s. b Ngā irahiko Raman in situ o Ni(OH)2-NS me c NiV-LDH-NS i roto i te 0.5 M KOH + 0.4 M cyclohexanone i ngā pūmanawa rerekē. d Ngā irahiko XANES in situ o Ni(OH)2-NS me NiV-LDH-NS i te Ni K-edge i roto i te 0.5 M KOH me e 0.5 M KOH me te 0.4 M cyclohexanone. E whakaatu ana te whakaurunga i tētahi rohe irahiko kua whakanuia i waenga i te 8342 me te 8446 eV. f Ngā āhua Valence o Ni i roto i te Ni(OH)2-NS me NiV-LDH-NS i ngā pūmanawa rerekē. g Ngā irahiko Ni EXAFS in situ o NiV-LDH-NS i mua atu, ā, i muri i te whakaurunga o te cyclohexanone i ngā pūmanawa rerekē. h Ngā tauira ariā o Ni(OH)2-NS me NiV-LDH-NS. Runga: I runga i te Ni(OH)2-NS, ko te whakarerekētanga puhoi mai i te Ni(OH)2-NS ki te NiOOH e mahi ana hei RDS, ko te cyclohexanone ia e whakaiti ana i te momo Ni teitei-valent mā roto i ngā mahi matū hei pupuri i te āhua Ni iti-valent hei whakaputa AA. Raro: I runga i te NiV-LDH-NS, ka āwhinahia te mahi whakarerekētanga e te whakarerekētanga V, ka hua ake te whakawhiti o te RDS mai i te mahi whakarerekētanga ki te mahi matū. i Ka huri te pūngao kore utu o Gibbs i te hanganga anō o Ni(OH)2-NS me NiV-LDH-NS. Kei roto i te kōnae raraunga mata ngā raraunga mata mō aj me i.
Hei tirotiro i te whanaketanga o ngā hanganga ngota me ngā hanganga hiko i te wā o te whakaiti i te whakakorikori, i whakahaerehia e mātou ngā whakamātautau X-ray absorption spectroscopy (XAS) in situ, i whakarato i tētahi taputapu kaha ki te tirotiro i ngā āhuatanga o ngā momo Ni i roto i ngā taahiraa e toru: OER, te werohanga cyclohexanone, me te COR i te pūmanawa ara iahiko tuwhera (OCP). E whakaatu ana te pikitia i ngā spectra K-edge XANES o Ni me te pūmanawa e piki haere ana i mua me muri i te werohanga cyclohexanone (Pikitia 3d, e). I te pūmanawa kotahi, he pai ake te kaha o te taha absorption o NiV-LDH-NS i tō Ni(OH)2-NS (Pikitia 3d, e, whakaurunga). Ko te valence toharite o Ni i raro i ia āhuatanga i whakatauhia mā te taunga honohono raina o ngā spectra XANES me te whakahokinga o te nekehanga kaha absorption Ni K-edge (Pikitia 3f), me te spectra tohutoro i tangohia mai i ngā tuhinga kua whakaputaina (Pikitia Tāpiri 23)43.
I te taahiraa tuatahi (i mua i te whakaurunga o te cyclohexanone, e rite ana ki te tukanga OER; Pikitia 3f, maui), i te pūmanawa o te whakakorikori kāore i hangaia (<1.3 VRHE), he iti ake te āhua o te valence o Ni i roto i te NiV-LDH-NS (+1.83) i tērā o te Ni(OH)2-NS (+1.97), ka taea te kī ko te whakawhiti irahiko mai i te V ki te Ni, e rite ana ki ngā hua XPS kua whakahuatia i runga ake nei (Pikitia 2f). Ina nui ake te pūmanawa i te pūwāhi whakaiti (1.5 VRHE), ka whakaatu te āhua valence o Ni i roto i te NiV-LDH-NS (+3.28) i te pikinga mārama ake i tērā o te Ni(OH)2-NS (+2.49). I te pūmanawa teitei ake (1.8 VRHE), he teitei ake te āhua valence o ngā matūriki Ni i whiwhihia i runga i te NiV-LDH-NS (+3.64) i tērā o te Ni(OH)2-NS (+3.47). E ai ki ngā pūrongo hou, e rite ana tēnei tukanga ki te hanganga o ngā momo Ni4+ tino kaha i roto i te hanganga o Ni3+xOOH1-x (he momo whakauru a Ni3+x o Ni3+ me Ni4+), kua whakaatu i mua i te kaha whakateretere whakarei ake i roto i te tangohanga waikura38,39,44. Nō reira, ko te mahi pai ake o NiV-LDH-NS i roto i te COR tērā pea nā te kaha whakahekenga whakarei ake hei hanga i ngā momo Ni tino kaha kaha.
I te taahiraa tuarua (te whakaurunga o te cyclohexanone i muri i te whakatuwheratanga o te mowhiti, Pikitia 3f), i tino heke te āhua valence o Ni i runga i ngā whakakorikori e rua, e rite ana ki te tukanga whakaiti o Ni3+xOOH1-x e te cyclohexanone, e rite ana ki ngā hua o te in situ Raman spectroscopy (Pikitia 3a), ā, kua tata te hokinga mai o te āhua valence o Ni ki te āhua tīmatanga (te taahiraa tuatahi i te iti o te pūmanawa), e tohu ana i te taea te huri i te tukanga redox o Ni ki Ni3+xOOH1-x.
I te taahiraa tuatoru (tukanga COR) i ngā pūmanawa COR (1.5 me te 1.8 VRHE; Pikitia 3f, matau), he iti noa te pikinga o te āhua valence o Ni i roto i te Ni(OH)2-NS (+2.16 me te +2.40), he iti iho i te pūmanawa kotahi i te taahiraa tuatahi (+2.49 me te +3.47). E whakaatu ana ēnei hua i muri i te werohanga cyclohexanone, ka whakawhāitihia te COR e te waikura puhoi o te Ni2+ ki te Ni3+x (arā, te hanga anō o te Ni) kaua e te taahiraa matū i waenga i te NiOOH me te cyclohexanone i runga i te Ni(OH)2-NS, e waiho ana te Ni i roto i te āhua valence iti. Nō reira, ka whakatau mātou ka taea e te hanga anō o te Ni te mahi hei RDS i roto i te tukanga COR i runga i te Ni(OH)2-NS. I te rerekētanga, i mau tonu te NiV-LDH-NS i te uara teitei o ngā momo Ni (>3) i te wā o te tukanga COR, ā, he iti iho te hekenga o te uara (iti iho i te 0.2) i whakaritea ki te taahiraa tuatahi i te pūmanawa kotahi (1.65 me te 1.8 VRHE), e tohu ana ko te whakarerekētanga V i whakatairanga i te waikura o Ni2+ ki Ni3+x, ka tere ake te tukanga whakaiti Ni i te taahiraa matū o te whakaiti cyclohexanone. I whakaatuhia hoki e ngā hua o te hanganga pai mimiti hihi-X whānui (EXAFS) te huringa katoa o ngā hononga Ni–O (mai i te 1.6 ki te 1.4 Å) me Ni–Ni(V) (mai i te 2.8 ki te 2.4 Å) i te aroaro o te cyclohexanone. He rite tēnei ki te hanga anō o te wāhanga Ni(OH)2 ki te wāhanga NiOOH me te whakaiti matū o te wāhanga NiOOH e te cyclohexanone (Pikitia 3g). Heoi, i tino ārai te cyclohexanone i te tere whakaheke o te Ni(OH)2-NS (tirohia te Tuhipoka Tāpiri 4 me te Pikitia Tāpiri 24 mō ētahi atu kōrero).
I te nuinga, i runga i te Ni(OH)2-NS (Pikitia 3h, runga), ko te taahiraa whakaheke puhoi mai i te wahanga Ni(OH)2 ki te wahanga NiOOH ka noho hei RDS o te tukanga COR whānui kaua ki te taahiraa matū o te hanganga AA mai i te cyclohexanone i te wā o te whakahekenga matū o te NiOOH. I runga i te NiV-LDH-NS (Pikitia 3h, raro), ka whakarei ake te whakarerekētanga V i te kinetics waikura o te Ni2+ ki te Ni3+x, ā, ka tere ake te hanganga o te NiVOOH (kaua ki te kai mā te whakahekenga matū), e neke ana i te RDS ki te taahiraa matū. Hei mārama ki te hanga anō o te Ni i puta mai i te whakarerekētanga V, i whakahaerehia e mātou ētahi atu tātaitanga ariā. E ai ki te whakaaturanga i te Pikitia 3h, i whakatauira mātou i te tukanga hanga anō o te Ni(OH)2-NS me te NiV-LDH-NS. Ka tangohia te protonation o ngā rōpū hydroxyl whatunga i runga i te Ni(OH)2-NS me te NiV-LDH-NS mā te tango i te OH- i roto i te electrolyte hei hanga i te hāora whatunga kore-irahiko. Ko ngā tauhohenga matū e rite ana ko:
I tatauhia te huringa pūngao kore utu Gibbs o te hanga anō (Pikitia 3i), ā, i whakaatu a NiV-LDH-NS (0.81 eV) i te huringa pūngao kore utu Gibbs he iti ake i te Ni(OH)2-NS (1.66 eV), e tohu ana i te whakaiti a te whakarerekētanga V i te ngaohiko e hiahiatia ana mō te hanga anō Ni. E whakapono ana mātou mā te whakatairanga i te hanga anō ka whakaiti i te arai pūngao o te COR katoa (tirohia te rangahau tikanga tauhohenga i raro nei mō ētahi atu taipitopito), ā, ka tere ake te tauhohenga i ngā kiato iahiko teitei ake.
E whakaatu ana te tātari i runga ake nei ko te whakarerekētanga V ka puta he whakarerekētanga ā-wāhanga tere o te Ni(OH)2, ā, ka piki ake te tere o te tauhohenga, ā, ko te kiato o te iahiko COR. Heoi, ka taea hoki e ngā pae Ni3+x te whakatairanga i te mahi OER. Mai i te pihi LSV me te kore he cyclohexanone, e kitea ana ko te kiato o te iahiko o NiV-LDH-NS he teitei ake i te Ni(OH)2-NS (Pikitia Tāpiri 19), e puta ai ngā tauhohenga COR me OER ki te hanga tauhohenga whakataetae. Nō reira, ko te FE teitei ake o te AA i te NiV-LDH-NS kāore e taea te whakamārama katoa mā te whakarerekētanga V e whakatairanga ana i te whakarerekētanga ā-wāhanga.
E whakaaetia whānuitia ana i roto i ngā pāpāho kawakore, ko ngā tauhohenga waikura hiko o ngā matūriki nucleophilic ka whai i te tauira Langmuir–Hinshelwood (LH). Ina koa, ko te matūriki me ngā anion OH− ka whakataetae te mimiti i runga i te mata o te whakakorikori, ā, ko te OH− kua mimitihia ka waikurahia ki ngā rōpū hydroxyl hohe (OH*), e mahi ana hei electrophiles mō te waikura o ngā nucleophiles, he tikanga kua whakaaturia i mua e ngā raraunga whakamātautau me/ranei ngā tātaitanga ariā45,46,47. Nō reira, ko te kukū o ngā matūriki tauhohe me tō rātou ōwehenga (te matūriki waro me te OH−) ka taea te whakahaere i te kapi o te matūriki tauhohe o te mata o te whakakorikori, ā, ka pā ki te FE me te hua o te hua ūnga14,48,49,50. I roto i tā mātou take, e whakapae ana mātou ko te kapi mata cyclohexanone teitei i roto i te NiV-LDH-NS ka pai ake te tukanga COR, ā, i tua atu, ko te kapi mata cyclohexanone iti i roto i te Ni(OH)2-NS ka pai ake te tukanga OER.
Hei whakamātautau i te whakapae i runga ake nei, i whakahaerehia tuatahitia e mātou ētahi raupapa whakamātautau e rua e pā ana ki te kukū o ngā matū tauhohe (C, cyclohexanone, me te COH−). I whakahaerehia te whakamātautau tuatahi me te electrolysis i te pūmanawa pumau (1.8 VRHE) i runga i ngā whakakorikori Ni(OH)2-NS me NiV-LDH-NS me ngā ihirangi cyclohexanone C rerekē (0.05 ~ 0.45 M) me te ihirangi COH− pumau (0.5 M). Kātahi ka tatauhia te hua FE me te AA. Mō te whakakorikori NiV-LDH-NS, i whakaatuhia e te whanaungatanga i waenga i te hua AA me te cyclohexanone C he pihi "momo puia" noa i roto i te aratau LH (Pikitia 4a), e tohu ana ko te kapi cyclohexanone teitei e whakataetae ana ki te mimiti OH−. Ahakoa mō te Ni(OH)2-NS, i piki haere te hua AA i te pikinga o te C o te cyclohexanone mai i te 0.05 ki te 0.45 M, e tohu ana ahakoa he teitei te kukū papatipu o te cyclohexanone (0.45 M), he iti tonu te kapi o te mata. Hei tāpiri, i te pikinga o te COH− ki te 1.5 M, i kitea he pihi "momo puia" i runga i te Ni(OH)2-NS i runga i te C o te cyclohexanone, ā, i whakaroahia te pūwāhi hurihuri o te mahi ki te whakataurite ki te NiV-LDH-NS, e whakaatu ana i te ngoikore o te mimiti o te cyclohexanone i runga i te Ni(OH)2-NS (Pikitia Tāpiri 25a me te Tuhipoka 5). Hei tāpiritanga, he tino tairongo te FE o te AA i runga i te NiV-LDH-NS ki te C-cyclohexanone, ā, i piki tere atu ki te neke atu i te 80% i te wā i whakanuia ai te C-cyclohexanone mai i te 0.05 M ki te 0.3 M, e tohu ana he ngāwari te whakanui i te cyclohexanone ki runga i te NiV-LDH-NS (Pikitia 4b). He rerekē, ko te whakanui ake i te kukū o te C-cyclohexanone kāore i tino aukati i te OER ki runga i te Ni(OH)2-NS, tērā pea nā te korenga o te mimiti o te cyclohexanone. He rerekē, ko te rangahau anō mō ​​te whakawhirinakitanga o te COH− ki te whai huatanga o te catalytic i whakaū anō hoki kua pai ake te mimiti o te cyclohexanone ki te NiV-LDH-NS, ka taea te aro atu ki te COH− teitei ake i te wā o te tukanga COR me te kore e whakaiti i te FE o te AA (Pikitia Tāpiri 25b, c me te Tuhipoka 5).
Te hua o te AA me te EF o te b Ni(OH)2-NS me te NiV-LDH-NS i runga i te cyclohexanone me ngā C rerekē i roto i te 0.5 M KOH. c Ngā pūngao adsorption o te cyclohexanone i runga i te NiOOH me te NiVOOH. d FE o te AA i runga i te Ni(OH)2-NS me te NiV-LDH-NS i roto i te 0.5 M KOH me te 0.4 M cyclohexanone i te 1.80 VRHE mā te whakamahi i ngā rautaki pūmanawa korekore me te pumau. Ko ngā pae hapa e tohu ana i te paerewa rerekētanga o ngā inenga motuhake e toru mā te whakamahi i te tauira kotahi, ā, kei roto i te 10%. e Runga: I runga i te Ni(OH)2-NS, ka mimiti ngoikore te cyclohexanone me te horahanga mata iti C e te cyclohexanone, ka hua ake he whakataetae kaha mō te OER. Raro: I runga i te NiV-LDH-NS, ka kitea he kukū mata teitei o te cyclohexanone C me te pikinga o te adsorption o te cyclohexanone, ka hua ake he pehi i te OER. Kei roto i te kōnae raraunga mata ngā raraunga mata mō a–d.
Hei whakamātautau i te mimititanga whakarei ake o te cyclohexanone ki runga i te NiV-LDH-NS, i whakamahia e mātou he taurite iti o te karaihe quartz honohono hiko (E-QCM) hei aroturuki i te huringa papatipu o te momo mimititanga i te wā tūturu. I whakaatuhia e ngā hua ko te kaha mimititanga tuatahi o te cyclohexanone ki runga i te NiV-LDH-NS he 1.6 ngā wā nui ake i tērā ki runga i te Ni(OH)2-NS i te āhua OCP, ā, ka piki ake tēnei rerekētanga i roto i te kaha mimititanga i te pikinga o te pūmanawa ki te 1.5 VRHE (Pikitia Tāpiri 26). I whakahaerehia ngā tataunga DFT porowhita-porowhita hei tirotiro i te whanonga mimititanga o te cyclohexanone ki runga i te NiOOH me te NiVOOH (Pikitia 4c). Ka piri te cyclohexanone ki te pokapū-Ni i runga i te NiOOH me te kaha piri (Eads) o te -0.57 eV, ko te cyclohexanone ia ka piri ki te pokapū-Ni, ki te pokapū-V rānei i runga i te NiVOOH, ā, he iti ake ngā Eads o te pokapū-V (-0.69 eV), e rite ana ki te piri kaha ake o te cyclohexanone i runga i te NiVOOH.
Hei whakamana anō i te kaha o te mimiti o te cyclohexanone ki te whakatairanga i te hanganga AA me te aukati i te OER, i whakamahia e mātou te rautaki pūmanawa motumotu hei whakarei ake i te cyclohexanone i runga i te mata o te whakakorikori (mō Ni(OH)2-NS me NiV-LDH-NS), i ahu mai i ngā pūrongo o mua. 51, 52 Ina koa, i whakamahia e mātou he pūmanawa o te 1.8 VRHE ki te COR, kātahi ka hurihia ki te āhua OCP, kātahi ka hurihia anō ki te 1.8 VRHE. I tēnei take, ka taea e te cyclohexanone te kohikohi ki runga i te mata o te whakakorikori i roto i te āhua OCP i waenga i ngā electrolyses (tirohia te wāhanga Tikanga mō ngā tikanga taipitopito). I whakaatuhia e ngā hua mō Ni(OH)2-NS me NiV-LDH-NS, mā te whakamahi i te electrolysis pūmanawa motumotu ka pai ake te mahi catalytic ki te whakataurite ki te electrolysis pūmanawa pumau (Pikitia 4d). He mea nui, i whakaatu te Ni(OH)2-NS i tētahi whakapainga nui ake i roto i te COR (AA FE: mai i te 51% ki te 82%) me te pehi i te OER (O2 FE: mai i te 27% ki te 4%) i te NiV-LDH-NS, i ahu mai i te meka ka taea te whakapai ake i te kohikohinga cyclohexanone ki tētahi taumata nui ake i runga i te whakakorikori me te kaha mimiti ngoikore (arā, Ni(OH)2-NS) mā te electrolysis pūmanawa wā-poto.
I te nuinga, ko te aukati i te OER i runga i te NiV-LDH-NS ka taea te kī ko te pikinga o te mimiti o te cyclohexanone (Pikitia 4e). I runga i te Ni(OH)2-NS (Pikitia 4e, runga), ko te ngoikore o te mimiti o te cyclohexanone i hua ake he iti te kapi o te cyclohexanone me te kapi o te OH* teitei i runga i te mata o te whakakorikori. Nō reira, ko te nui o ngā momo OH* ka arahi ki te whakataetae nui mō te OER me te whakaiti i te FE o te AA. He rerekē, i runga i te NiV-LDH-NS (Pikitia 4e, raro), ko te whakarerekētanga V i whakanui ake i te kaha mimiti o te cyclohexanone, nā reira i whakanui ake ai i te mata C o te cyclohexanone me te whakamahi pai i ngā momo OH* kua mimitihia mō te COR, e whakatairanga ana i te hanganga AA me te aukati i te OER.
Haunga te tirotiro i te pānga o te whakarerekētanga V ki te hanga anō i ngā momo Ni me te mimiti o te cyclohexanone, i tirotirohia anō hoki e mātou mēnā ka whakarerekē a V i te ara hanganga AA mai i te COR. He maha ngā ara COR rerekē kua whakaarohia i roto i ngā tuhinga, ā, i tātarihia e mātou ō rātou āheinga i roto i tā mātou pūnaha tauhohenga (tirohia te Pikitia Tāpiri 27 me te Tuhipoka Tāpiri 6 mō ētahi atu taipitopito)13,14,26. Tuatahi, kua pūrongohia ko te taahiraa tuatahi o te ara COR ka uru pea ki te waikura tuatahi o te cyclohexanone hei hanga i te takawaenga matua 2-hydroxycyclohexanone (2)13,14. Hei manatoko i te tukanga, i whakamahia e mātou te 5,5-dimethyl-1-pyrrolidine N-oxide (DMPO) hei hopu i ngā takawaenga hohe i mimitihia ki te mata o te whakakorikori, ā, i akohia te EPR. I whakaatuhia e ngā hua EPR te aroaro o ngā rauropi C-centered (R) me ngā rauropi hydroxyl (OH) i runga i ngā whakakorikori e rua i te wā o te tukanga COR, e tohu ana ko te dehydrogenation Cα − H o te cyclohexanone ka hanga i tētahi rauropi enolate takawaenga (1), ka whakakorikoria anō e te OH* hei hanga i te 2 (Pikitia 5a me te Pikitia Tāpiri 28). Ahakoa i kitea ngā takawaenga ōrite i runga i ngā whakakorikori e rua, ko te wāhanga horahanga o te tohu R i runga i te NiV-LDH-NS he teitei ake i tērā o te Ni(OH)2-NS, tērā pea nā te kaha adsorption whakarei ake o te cyclohexanone (Ripanga Tāpiri 3 me te Tuhipoka 7). I whakamahia anō e mātou te 2 me te 1,2-cyclohexanedione (3) hei tīmatanga tauhohenga mō te electrolysis hei whakamātautau mēnā ka whakarerekē a V i te taahiraa whakakorikori e whai ake nei. Ko ngā hua o te hikohiko o ngā takawaenga pūmanawa (2 me te 3) i runga i te Ni(OH)2-NS me te NiV-LDH-NS i whakaatu i ngā kōwhiringa hua rite, e tohu ana i te haere tonu o te tauhohenga COR i runga i te Ni(OH)2-NS, i te NiV-LDH-NS rānei mā ngā ara ōrite (Pikitia 5b). Heoi anō, ko te AA te hua matua i te wā i whakamahia ai te 2 hei tauhohenga, e kī ana i whiwhihia te AA mā te tukanga waikura tika mā te wehenga o te here Cα − Cβ o te 2 kaua ki te waikura i muri mai ki te 3 i runga i ngā whakakorikori e rua, nā te mea i hurihia te nuinga ki te GA i te wā i whakamahia ai te 3 hei tauhohenga tīmatanga (Ngā Pikitia Tāpiri 29, 30).
Tohu EPR o NiV-LDH-NS i roto i te 0.5 M KOH + 0.4 M cyclohexanone. b Ngā hua o te tātaritanga hiko o te 2-hydroxycyclohexanone (2) me te 1,2-cyclohexanedione (3). I whakahaerehia te hiko i roto i te 0.5 M KOH me te 0.1 M 2, 3 rānei i te 1.8 VRE mō te haora kotahi. Ko ngā pae hapa e tohu ana i te paerewa rerekētanga o ngā inenga motuhake e rua e whakamahi ana i te whakakorikori kotahi. c Ngā ara tauhohenga kua whakaarohia o COR i runga i ngā whakakorikori e rua. d Whakaahua kauwhata o te ara COR i runga i te Ni(OH)2-NS (maui) me te d NiV-LDH-NS (matau). Ko ngā pere whero e tohu ana i ngā mahi e whakatairangahia ana e te whakarerekētanga V i roto i te tukanga COR. Kei roto i te kōnae raraunga mata ngā raraunga mata mō a me b.
I te nuinga, i whakaaturia e mātou ko Ni(OH)2-NS me NiV-LDH-NS te kaiwhakaoho i te COR mā te ara ōrite: ka mimitihia te cyclohexanone ki runga i te mata o te kaiwhakaoho, ka tangohia te hauwai, ka ngaro ngā irahiko hei hanga 1, kātahi ka whakahāweatia e te OH* hei hanga 2, ā, ka whai ake ko ngā panonitanga maha-taahiraa hei hanga AA (Pikitia 5c). Heoi, i te whakamahinga o te cyclohexanone hei tauhohenga, i kitea te whakataetae OER i runga i te Ni(OH)2-NS anake, ko te iti rawa o te hāora i kohia i te whakamahinga o te 2 me te 3 hei tauhohenga. Nō reira, ko ngā rerekētanga i kitea i roto i te mahi whakaoho ka puta pea i ngā huringa o te arai pūngao RDS me te kaha mimiti cyclohexanone i puta mai i te whakarerekētanga V kaua i ngā huringa o te ara tauhohenga. Nō reira, i tātarihia e mātou te RDS o ngā ara tauhohenga i runga i ngā kaiwhakaoho e rua. Ko ngā hua o te tirotiro ā-oro X-ray in situ kua whakahuatia ake nei e whakaatu ana ko te whakarerekētanga V ka neke i te RDS i roto i te tauhohenga COR mai i te wāhanga hanga anō ki te wāhanga matū, me te pupuri tonu i te wāhanga NiOOH me ngā momo Ni-rahi-valent i runga i te NiV-LDH-NS (Pikitia 3f, Pikitia Tāpiri 24, me te Tuhipoka 4). I tātarihia anō e mātou ngā tukanga tauhohenga e tohuhia ana e te kiato o ia wāhanga o ngā rohe pūmanawa rerekē i te wā o te ine CV (tirohia te Pikitia Tāpiri 31 me te Tuhipoka 8 mō ngā taipitopito) ā, i whakahaerehia ngā whakamātautau whakawhiti isotope kinetic H/D, i whakaatu ngātahi ko te RDS o te COR i runga i te NiV-LDH-NS e uru ana ki te wehenga o te here Cα − H i roto i te wāhanga matū kaua ki te wāhanga whakaiti (tirohia te Pikitia Tāpiri 32 me te Tuhipoka 8 mō ētahi atu taipitopito).
I runga i te tātaritanga o runga ake nei, ko te pānga whānui o te whakarerekētanga V e whakaaturia ana i te Pikitia 5d. Ka hangaia anōtia te mata o ngā whakakōkī Ni(OH)2-NS me NiV-LDH-NS i ngā pūmanawa anodic teitei, ā, ka whakakōkī i te COR mā te ara ōrite. I runga i te Ni(OH)2-NS (Pikitia 5d, maui), ko te taahiraa hanga anō ko te RDS i te wā o te tukanga COR; i runga i te NiV-LDH-NS (Pikitia 5d, matau), i tere ake te tukanga hanga anō i te whakarerekētanga V, ā, i hurihia te RDS ki te Cα−H dehydrogenation o te cyclohexanone hei hanga 1. Hei tāpiri, i puta te adsorption cyclohexanone i te pae V, ā, i whakanuia ake i runga i te NiV-LDH-NS, i whai wāhi ki te pehi i te OER.
I runga i te whakaaro ki te mahi hiko-whakakorikori pai rawa atu o NiV-LDH-NS me te FE teitei i runga i te whānuitanga o te pūmanawa, i hangaia e mātou he MEA hei whakatutuki i te whakaputanga tonu o te AA. I huihuia te MEA mā te whakamahi i te NiV-LDH-NS hei anode, te PtRu/C arumoni hei cathode53 me te membrane whakawhiti anion (momo: FAA-3-50) (Pikitia 6a me te Pikitia Tāpiri 33)54. I te mea kua heke te ngaohiko pūtau, ā, he rite te FE o te AA ki te 0.5 M KOH i roto i te rangahau i runga ake nei, i arotauhia te kukū anolyte ki te 1 M KOH (Pikitia Tāpiri 25c). Kei te whakaatuhia ngā kōpiko LSV kua tuhia i roto i te Pikitia Tāpiri 34, e tohu ana ko te whai huatanga COR o NiV-LDH-NS he nui ake i te Ni(OH)2-NS. Hei whakaatu i te hiranga o NiV-LDH-NS, i whakahaerehia te electrolysis au pumau me te kiato au taahiraa mai i te 50 ki te 500 mA cm−2, ā, i tuhia te ngaohiko pūtau e rite ana. I whakaatuhia e ngā hua he 1.76 V te ngaohiko pūtau o NiV-LDH-NS i te mātotoru o te iahiko o te 300 mA cm−2, he tata ki te 16% te iti iho i tērā o Ni(OH)2-NS (2.09 V), e tohu ana i tōna pai ake o te kaha i roto i te whakaputanga AA (Pikitia 6b).
Kauwhata hoahoa o te pākahiko rere. b Ngaohiko pūtau me te kore utu iR i runga i te Ni(OH)2-NS me te NiV-LDH-NS i roto i te 1 M KOH me te 0.4 M cyclohexanone i ngā kiato iahiko rerekē. c Te hua AA me te FE i runga i te Ni(OH)2-NS me te NiV-LDH-NS i ngā kiato iahiko rerekē. Ko ngā pae hapa e tohu ana i te paerewa rerekētanga o ngā inenga motuhake e rua e whakamahi ana i te whakakorikori kotahi. d Te whakataurite i te mahi whakakorikori o tā mātou mahi me ētahi atu pūnaha pākahiko rere kua pūrongohia14,17,19. Kua whakarārangihia ngā tawhā tauhohenga me ngā āhuatanga tauhohenga i roto i te Ripanga Tāpiri 2. e Ngaohiko pūtau me te FE o te AA i runga i te NiV-LDH-NS i te 200 me te 300 mA cm−2 i roto i te whakamātautau roa, ia. Ko ngā raraunga mata mō te be ka whakaratohia hei kōnae raraunga mata.
I taua wā tonu, e ai ki te whakaaturanga i te Pikitia 6c, i mau tonu te NiV-LDH-NS i te FE pai (83% ki te 61%) i te kiato iahiko teitei ake (200 ki te 500 mA cm-2), nā reira i whakapai ake ai i te hua o te AA (1031 ki te 1900 μmol cm-2 h-1). I taua wā tonu, 0.8% noa iho o ngā anion waikawa adipic i kitea i roto i te wāhanga cathode i muri i te electrolysis, e tohu ana kāore i te nui te whakawhiti cyclohexanone i roto i tā mātou take (Pikitia Tāpiri 35). He rerekē, me te tere pikinga ōrite o te kiato iahiko, i heke te FE o te AA i runga i te Ni(OH)2-NS mai i te 61% ki te 34%, nā reira i uaua ai te whakapai ake i te hua o te AA (762 ki te 1050 μmol cm-2 h-1). Ina koa, i paku heke te mahi a te AA nā te kaha o te whakataetae mai i te OER, ā, nō reira i tino heke te FE o te AA me te pikinga o te kiato o te iahiko (mai i te 200 ki te 250 mA cm−2, Tāpiritanga Pikitia 5). Ki tā mātou e mōhio ana, ko ngā hua whakaterenga e whakamahi ana i te MEA me ngā whakaterenga NiV-LDH-NS he nui ake i te mahi a ngā tauhohenga rere i kōrerotia i mua me ngā whakaterenga e hangai ana ki te Ni (Ripanga Tāpiri 2). I tua atu, e whakaaturia ana i te Pikitia 6d, i whakaatu a NiV-LDH-NS i ngā painga nui e pā ana ki te kiato o te iahiko, te ngaohiko pūtau, me te FE o te AA ki te whakataurite ki te whakaterenga e hangai ana ki te Co te mahi pai rawa atu, arā, te Co3O4 tautokona e te graphene (Co3O4/GDY)17. I tua atu, i arotakehia e mātou te whakapaunga pūngao o te hanga AA, ā, i whakaaturia he tino iti te whakapaunga AA, 2.4 W h gAA-1 anake i te kiato o te iahiko o te 300 mA cm-2 me te ngaohiko pūtau o te 1.76 V (kei roto i te Tuhipoka Tāpiri 1 ngā tātaitanga taipitopito). Ki te whakatauritea ki te hua pai rawa atu o te 4.1 W h gAA-1 mō te Co3O4/GDY i kōrerotia i mua, i whakaitihia te whakapaunga pūngao mō te hanga AA i roto i tā mātou mahi mā te 42%, ā, i piki ake te hua mā te 4 ngā wā (1536 vs. 319 μmol cm-2 h-1)17.
I arotakehia te pumau o te whakakorikori NiV-LDH-NS mō te whakaputanga AA mō te wā roa i roto i te MEA i ngā kiato o te au o te 200 me te 300 mA cm-2, ia (Pikitia 6e). Nā te mea ka tere ake te paunga o te OH− i ngā kiato o te au teitei ake, he teitei ake te tere whakahou irahiko i te 300 mA cm-2 i tērā i te 200 mA cm-2 (tirohia te wāhanga iti "Ngā inenga hiko" mō ētahi atu kōrero). I te kiato o te au o te 200 mA cm-2, ko te toharite o te whai huatanga o te COR he 93% i ngā haora tuatahi e 6, kātahi ka heke paku ki te 81% i muri i te 60 haora, i te mea ka piki paku te ngaohiko pūtau mā te 7% (mai i te 1.62 V ki te 1.73 V), e tohu ana i te pumau pai. I te pikinga o te kiato o te iahiko ki te 300 mA cm−2, tata tonu te kore e rerekē te whai huatanga o te AA (i heke mai i te 85% ki te 72%), engari i tino piki ake te ngaohiko o te pūtau (mai i te 1.71 ki te 2.09 V, e rite ana ki te 22%) i te wā o te whakamātautau 46-hāora (Pikitia 6e). E whakapae ana mātou ko te take matua mō te hekenga o te mahi ko te waikura o te kiriuhi whakawhiti anion (AEM) e te cyclohexanone, e hua ake ai te pikinga o te ātete pūtau me te ngaohiko o te pūtau electrolyzer (Pikitia Tāpiri 36), me te turuturu iti o te electrolyte mai i te anode ki te cathode, ka hua ake te hekenga o te rōrahi anolyte me te hiahia kia mutu te electrolysis. Hei tāpiri, ko te hekenga o te FE o te AA ka puta pea i te rerenga o ngā catalysts, e pai ake ai te whakatuwheratanga o te pahuka Ni mō te OER. Hei whakaatu i te pānga o te AEM kua waikura ki te whakahekenga o te pumau i te 300 mA cm−2, i whakakapia e mātou ki tētahi AEM hou i muri i te 46 hāora o te hikohiko. E ai ki te whakaaro, i tino whakahokia mai te pai o te whakaterenga, me te hekenga nui o te ngaohiko pūtau ki te uara tīmatanga (mai i te 2.09 ki te 1.71 V) kātahi ka piki ake i roto i ngā hāora 12 e whai ake nei o te hikohiko (mai i te 1.71 ki te 1.79 V, he pikinga o te 5%; Pikitia 6e).
I te nuinga, i taea e mātou te whakatutuki i te pumau tonu o te whakaputanga AA mō te 60 hāora i te kiato o te iahiko o te 200 mA cm−2, e tohu ana kei te pai te pupuri i te FE me te ngaohiko pūtau o te AA. I whakamātauhia hoki e mātou he kiato o te iahiko teitei ake o te 300 mA cm−2, ā, i tutuki i a mātou te pumau katoa o te 58 hāora, me te whakakapi i te AEM ki tētahi mea hou i muri i te 46 hāora. E whakaatu ana ngā rangahau o runga ake nei i te pumau o te whakakorikori, ā, e whakaatu mārama ana i te hiahia mō te whanaketanga o ngā AEM kaha ake ā muri ake nei hei whakapai ake i te pumau roa o te MEA mō te whakaputanga AA tonu i ngā kiato o te iahiko pai rawa atu o te ahumahi.
I runga i te mahi a tā mātou MEA, i whakaarohia e mātou he tukanga whakaputa AA katoa tae atu ki te whāngai i te papa, te hikohiko, te whakakorekore, me ngā waeine wehewehe (Pikitia Tāpiri 37). I whakahaerehia he tātari mahi tuatahi hei aromatawai i te whaihua ōhanga o te pūnaha mā te whakamahi i tētahi tauira whakaputa carboxylate electrocatalytic electrolyte alkaline55. I tēnei take, ko ngā utu kei roto ko te whakapaipai, ngā mahi, me ngā rauemi (Pikitia 7a me te Pikitia Tāpiri 38), ā, ko ngā moni whiwhi ka puta mai i te whakaputanga AA me te H2. E whakaatu ana ngā hua TEA i raro i ā mātou tikanga whakahaere (kiato o nāianei 300 mA cm-2, ngaohiko pūtau 1.76 V, FE 82%), ko te tapeke o ngā utu me ngā moni whiwhi he US$2429 me te US$2564, ia, e whakawhiti ana ki te hua kupenga o te US$135 mō ia tana o te AA i hangaia (tirohia te Tuhipoka Tāpiri 9 mō ngā taipitopito).
a Te utu katoa o te tukanga hikohiko AA i raro i te horopaki take turanga me te FE o te 82%, te kiato o ia au o te 300 mA cm−2, me te ngaohiko pūtau o te 1.76 V. Te tātari aro o ngā utu e toru ki te kiato o ia au o te FE me te c. I roto i te tātari aro, ko ngā tawhā i akohia anake i whakarerekētia, ā, i puritia kia rite tonu ngā tawhā kē atu i runga i te tauira TEA. d Ngā pānga o te FE rerekē me te kiato o ia au ki te hua o te hanga hiko AA me te hua mā te whakamahi i te Ni(OH)2-NS me te NiV-LDH-NS, me te whakaaro kei te puritia kia rite tonu te ngaohiko pūtau ki te 1.76 V. Ko ngā raraunga whakauru mō a–d kei roto i te kōnae raraunga mata.
I runga i tēnei ariā, i tirotirohia anōtia e mātou te pānga o te FE me te mātotoru o te au ki te hua o te hanga hiko AA. I kitea e mātou he tino pārekareka te hua ki te FE o te AA, nā te mea ko te hekenga o te FE ka hua ake he pikinga nui o te utu whakahaere, ā, ka nui ake te utu whānui (Pikitia 7b). Mō te mātotoru o te au, ko te mātotoru o te au teitei ake (>200 mA cm-2) ka āwhina ki te whakaiti i te utu whakapaipai me te utu hanga tipu, mā te whakaiti i te horahanga pūtau hiko, ā, ka whai wāhi ki te pikinga o te hua (Pikitia 7c). Ki te whakatauritea ki te mātotoru o te au, he nui ake te pānga o te FE ki te hua. Mā te whakaahua i te pānga o te FE me te mātotoru o te au ki te hua, ka kitea mārama e mātou te hiranga o te whakatutuki i te FE teitei (>60%) i ngā mātotoru o te au e tika ana mō te ahumahi (>200 mA cm-2) kia pai ai te hua. Nā te uara FE teitei o te AA, kei te pai tonu te pūnaha tauhohenga me te NiV-LDH-NS hei whakakorikori i roto i te awhe o te 100–500 mA cm−2 (ngā ira pentagram; Pikitia 7d). Heoi, mō Ni(OH)2-NS, ko te whakaiti i te FE i te kiato au teitei (>200 mA cm−2) i hua ake ai ngā hua kino (porowhita; Pikitia 7d), e whakaatu ana i te hiranga o ngā whakakorikori me te FE teitei i te kiato au teitei.
Haunga te hiranga o ngā whakakorikori ki te whakaiti i ngā utu whakapaipai me ngā utu whakahaere, e kī ana tā mātou aromatawai TEA ka taea te whakapai ake i te hua i roto i ngā huarahi e rua. Ko te tuatahi ko te hoko tahi i te pāhare pākawa waro (K2SO4) ki te mākete hei hua taha o te waeine whakakore, engari me te moni whiwhi pea o te US$828/t AA-1 (Tuhipoka Tāpiri 9). Ko te tuarua ko te arotau i te hangarau tukatuka, tae atu ki te hangarua rauemi, te whakawhanake rānei i ngā hangarau wehewehe AA utu nui ake (hei whakakapi i ngā waeine whakakore me te wehenga). Ko te tukanga whakakore waikawa-pūtake e whakamahia ana i tēnei wā ka hua ake he utu nui mō ngā rauemi (koinei te wāhanga nui rawa atu i te 85.3%), ko te 94% o ēnei nā te cyclohexanone me te KOH ($2069/t AA-1; Pikitia 7a), engari e ai ki te kōrero i runga ake nei, he hua tonu te tukanga whānui. E whakaaro ana mātou me whakaiti ake ngā utu rauemi mā roto i ngā tikanga matatau ake mō te whakaora i te KOH me te cyclohexanone kāore i tauhohe, pērā i te electrodialysis hei whakaora katoa i te KOH14 (te utu whakatau tata o US$1073/t AA-1 mā te electrodialysis; Tuhipoka Tāpiri 9).
Hei whakarāpopototanga, i tutuki i a mātou te whai huatanga teitei o te electrolysis ngota konumohe i te kiato au teitei mā te whakauru i te V ki roto i ngā nanosheets Ni(OH)2. I raro i te whānuitanga pūmanawa whānui o te 1.5–1.9 VRHE me te kiato au teitei o te 170 mA cm−2, i eke te AA FE i runga i te NiV-LDH-NS ki te 83–88%, i te mea i pehia pai te OER ki te 3%. I whakatairanga te whakarerekētanga V i te whakahekenga o te Ni2+ ki te Ni3+x, ā, i whakarei ake i te mimiti o te cyclohexanone. E whakaatu ana ngā raraunga whakamātautau me ngā raraunga ariā ko te hanga hou whakaohooho ka whakanui ake i te kiato au mō te waikura cyclohexanone, ā, ka nekehia te RDS o te COR mai i te hanga hou ki te dehydrogenation e uru ana ki te tapahi Cα − H, i te mea ka pehia e te mimiti whakarei ake o te cyclohexanone te OER. I tutuki i te whanaketanga o te MEA te whakaputanga AA tonu i te kiato au ahumahi o te 300 mA cm−2, he pai rawa atu te AA o te 82%, me te hua o te 1536 μmol cm−2 h−1. I whakaatuhia i roto i tētahi whakamātautau 50-hāora he pai te pumau o NiV-LDH-NS nā te mea ka taea e ia te pupuri i te AA FE teitei i roto i te MEA (> 80% mō ngā hāora 60 i te 200 mA cm−2; > 70% mō ngā hāora 58 i te 300 mA cm−2). Me mōhio kei te hiahiatia he AEM kaha ake hei whakatutuki i te pumau mō te wā roa i ngā kiato iahiko pai rawa atu o te ahumahi. Hei tāpiri, e whakaatu ana te TEA i ngā painga ōhanga o ngā rautaki tauhohenga mō te hanga AA me te hiranga o ngā whakakorikori mahi-teitei me ngā hangarau wehenga matatau hei whakaiti ake i ngā utu.