Industrial water splitting has long been suppressed by the sluggish kinetics of the oxygen evolution reaction(OER),which requires a catalyst to be efficient.Herein,we propose a molecular-level proton acceptor strategy...Industrial water splitting has long been suppressed by the sluggish kinetics of the oxygen evolution reaction(OER),which requires a catalyst to be efficient.Herein,we propose a molecular-level proton acceptor strategy to produce an efficient OER catalyst that can boost industrial-scale water splitting.Molecular-level phosphate(-PO_(4))group is introduced to modify the surface of PrBa_(0.5)Ca_(0.5)Co_(2)O_(5)+δ(PBCC).The achieved catalyst(PO_(4)-PBCC)exhibits significantly enhanced catalytic performance in alkaline media.Based on the X-ray absorption spectroscopy results and density functional theory(DFT)calculations,the PO_(4)on the surface,which is regarded as the Lewis base,is the key factor to overcome the kinetic limitation of the proton transfer process during the OER.The use of the catalyst in a membrane electrode assembly(MEA)is further evaluated for industrial-scale water splitting,and it only needs a low voltage of 1.66 V to achieve a large current density of 1 A cm^(-2).This work provides a new molecular-level strategy to develop highly efficient OER electrocatalysts for industrial applications.展开更多
Metal oxyhydroxides(MOOH)generated from irreversible reconstructions of transition metal compounds are intrinsic active species for oxygen evolution reaction,whose activities are still constrained by sluggish deproton...Metal oxyhydroxides(MOOH)generated from irreversible reconstructions of transition metal compounds are intrinsic active species for oxygen evolution reaction,whose activities are still constrained by sluggish deprotonation kinetics and inherent adsorption energy scaling relations.Herein,we construct a tunable proton acceptor(TPA)on oxyhydroxides by in-situ reconstruction of metal oxoacids such as NiC2O4to accelerate deprotonation and break adsorption energy scaling relations during OER.The modified C_(2)O_(4)^(2-)as a TPA can easily extract H of*OH(forming*HC2O4intermediate)and then promote deprotonation by the transmitted hydrogen bond with*OOH along conjugated(H...)O=C-O(-H)chain.As a result,Ni OOH-C2O4shows non-concerted proton-electron transfer and improved deprotonation rate,and delivers a good OER activity(270 mV@10 mA cm-2).The conjugate acidity coefficient(pKa)of the modified oxoacid group can be a descriptor for TPA selection.This TPA strategy can be universally applied to Co-,Fe-,and Ni-based oxyhydroxides to facilitate OER efficiency.展开更多
研究了以2,2′-亚甲基双(4,6-二叔丁基苯酚)(简称双酚Z)与三氯化磷为原料,经一级酯化反应生成2,2′-亚甲基双(4,6-二叔丁基苯基)亚磷酸酯一氯化物;与异辛醇二级酯化反应生成2,2′-亚甲基双(4,6-二叔丁基苯基)异辛烷氧基亚磷酸酯(简称HP-...研究了以2,2′-亚甲基双(4,6-二叔丁基苯酚)(简称双酚Z)与三氯化磷为原料,经一级酯化反应生成2,2′-亚甲基双(4,6-二叔丁基苯基)亚磷酸酯一氯化物;与异辛醇二级酯化反应生成2,2′-亚甲基双(4,6-二叔丁基苯基)异辛烷氧基亚磷酸酯(简称HP-10)。一级酯化工艺条件:n(双酚Z)∶n(三氯化磷)=1.0∶1.3,催化剂0.2g,反应时间2.0h,温度85.0℃;二级酯化工艺条件:异辛醇6.5g,缚酸剂13.0g,反应时间4.0h,温度85.0℃。合成HP-10收率达84.3%,熔点147.5～148.2℃,经IR1、H NMR、13 C NMR、LC-MS谱图解析,与HP-10结构相符,产物质量分数大于97.0%。展开更多
质子耦合电子转移(Proton coupled electron transfer,PCET)步骤存在于众多电催化与电合成反应中,通过调节PCET单元步骤来控制电催化反应热力学及动力学被证明是一种有效手段,同时,质子给/受体被证明是影响PCET反应的一个重要因素。本...质子耦合电子转移(Proton coupled electron transfer,PCET)步骤存在于众多电催化与电合成反应中,通过调节PCET单元步骤来控制电催化反应热力学及动力学被证明是一种有效手段,同时,质子给/受体被证明是影响PCET反应的一个重要因素。本文以电催化析氧、析氢、CO 2的电化学还原等典型电催化体系为例,探讨质子给/受体通过调控质子耦合电子转移单元步骤继而影响电催化反应的多种机制。展开更多
Fluorescence quenching processes of poly[2-methoxy-5-(2'ethyl-hexoxy)-p-phenylene vinylene] (MEH-PPV) in solution by electron acceptors, O2 and acid, have been studied. Static quenching of the fluorescence fromMEH...Fluorescence quenching processes of poly[2-methoxy-5-(2'ethyl-hexoxy)-p-phenylene vinylene] (MEH-PPV) in solution by electron acceptors, O2 and acid, have been studied. Static quenching of the fluorescence fromMEH-PPV by an electron acceptor (DDQ or TCNE) occurs due to electron transfer from MEH-PPV to the electron acceptor and this electron transfer quenching can be promoted by chloroform. Photooxidation takes place in the MEH-PPV solution and singlet oxygen is an intermediate in the photooxidation, according to the results of ESR spectroscopy. Acid also plays an important role in the fluorescence quenching process of MEH-PPV, by the proto-nation of the alkoxy groups in the molecular chain.展开更多
基金supported by the National Natural Sci-ence Foundation of China(22272081),Jiangsu Provincial Specially Appointed Professors Foundation.
文摘Industrial water splitting has long been suppressed by the sluggish kinetics of the oxygen evolution reaction(OER),which requires a catalyst to be efficient.Herein,we propose a molecular-level proton acceptor strategy to produce an efficient OER catalyst that can boost industrial-scale water splitting.Molecular-level phosphate(-PO_(4))group is introduced to modify the surface of PrBa_(0.5)Ca_(0.5)Co_(2)O_(5)+δ(PBCC).The achieved catalyst(PO_(4)-PBCC)exhibits significantly enhanced catalytic performance in alkaline media.Based on the X-ray absorption spectroscopy results and density functional theory(DFT)calculations,the PO_(4)on the surface,which is regarded as the Lewis base,is the key factor to overcome the kinetic limitation of the proton transfer process during the OER.The use of the catalyst in a membrane electrode assembly(MEA)is further evaluated for industrial-scale water splitting,and it only needs a low voltage of 1.66 V to achieve a large current density of 1 A cm^(-2).This work provides a new molecular-level strategy to develop highly efficient OER electrocatalysts for industrial applications.
基金the support from the National Key R&D Program of China(2020YFA0710000)the National Natural Science Foundation of China(22278307,22222808,21978200)the Haihe Laboratory of Sustainable Chemical Transformations。
文摘Metal oxyhydroxides(MOOH)generated from irreversible reconstructions of transition metal compounds are intrinsic active species for oxygen evolution reaction,whose activities are still constrained by sluggish deprotonation kinetics and inherent adsorption energy scaling relations.Herein,we construct a tunable proton acceptor(TPA)on oxyhydroxides by in-situ reconstruction of metal oxoacids such as NiC2O4to accelerate deprotonation and break adsorption energy scaling relations during OER.The modified C_(2)O_(4)^(2-)as a TPA can easily extract H of*OH(forming*HC2O4intermediate)and then promote deprotonation by the transmitted hydrogen bond with*OOH along conjugated(H...)O=C-O(-H)chain.As a result,Ni OOH-C2O4shows non-concerted proton-electron transfer and improved deprotonation rate,and delivers a good OER activity(270 mV@10 mA cm-2).The conjugate acidity coefficient(pKa)of the modified oxoacid group can be a descriptor for TPA selection.This TPA strategy can be universally applied to Co-,Fe-,and Ni-based oxyhydroxides to facilitate OER efficiency.
文摘研究了以2,2′-亚甲基双(4,6-二叔丁基苯酚)(简称双酚Z)与三氯化磷为原料,经一级酯化反应生成2,2′-亚甲基双(4,6-二叔丁基苯基)亚磷酸酯一氯化物;与异辛醇二级酯化反应生成2,2′-亚甲基双(4,6-二叔丁基苯基)异辛烷氧基亚磷酸酯(简称HP-10)。一级酯化工艺条件:n(双酚Z)∶n(三氯化磷)=1.0∶1.3,催化剂0.2g,反应时间2.0h,温度85.0℃;二级酯化工艺条件:异辛醇6.5g,缚酸剂13.0g,反应时间4.0h,温度85.0℃。合成HP-10收率达84.3%,熔点147.5～148.2℃,经IR1、H NMR、13 C NMR、LC-MS谱图解析,与HP-10结构相符,产物质量分数大于97.0%。
文摘质子耦合电子转移(Proton coupled electron transfer,PCET)步骤存在于众多电催化与电合成反应中,通过调节PCET单元步骤来控制电催化反应热力学及动力学被证明是一种有效手段,同时,质子给/受体被证明是影响PCET反应的一个重要因素。本文以电催化析氧、析氢、CO 2的电化学还原等典型电催化体系为例,探讨质子给/受体通过调控质子耦合电子转移单元步骤继而影响电催化反应的多种机制。
基金the National Natural Science Foundation of China (No. 20173066) and the Major State Basic Research Development Program of China (No. G2000078100).
文摘Fluorescence quenching processes of poly[2-methoxy-5-(2'ethyl-hexoxy)-p-phenylene vinylene] (MEH-PPV) in solution by electron acceptors, O2 and acid, have been studied. Static quenching of the fluorescence fromMEH-PPV by an electron acceptor (DDQ or TCNE) occurs due to electron transfer from MEH-PPV to the electron acceptor and this electron transfer quenching can be promoted by chloroform. Photooxidation takes place in the MEH-PPV solution and singlet oxygen is an intermediate in the photooxidation, according to the results of ESR spectroscopy. Acid also plays an important role in the fluorescence quenching process of MEH-PPV, by the proto-nation of the alkoxy groups in the molecular chain.
