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
质子耦合电子转移(Proton-Coupled Electron Transfer,PCET)反应是生物和化学的重要过程,它与光合作用、呼吸过程、能量转化和存储,以及制备清洁能源材料等过程紧密相关。界面上的质子耦合电子转移反应是近年来的研究热点之一,本文对该...质子耦合电子转移(Proton-Coupled Electron Transfer,PCET)反应是生物和化学的重要过程,它与光合作用、呼吸过程、能量转化和存储,以及制备清洁能源材料等过程紧密相关。界面上的质子耦合电子转移反应是近年来的研究热点之一,本文对该领域进行了简要综述,主要介绍了发生在液/液界面和固/液界面上的质子耦合电子转移反应的研究进展。展开更多
The mechanism of the proton_transfer_coupled electron transfer (PT_ET) reactions between the menaquinone Q A (MQ 1) and ubiquinone Q B (UQ 1) in the bacterial photosynthetic reaction center of Rhodopseudomona vi...The mechanism of the proton_transfer_coupled electron transfer (PT_ET) reactions between the menaquinone Q A (MQ 1) and ubiquinone Q B (UQ 1) in the bacterial photosynthetic reaction center of Rhodopseudomona viridis was studied by using the B3LYP/6_31G(d) method. The changes of standard Gibbs free energy ΔG 0 of all possible reactions followed the ET reaction (1) were calculated. The results indicated that: (1) according to the ΔG 0 values of corresponding reactions, UQ 1 could not accept two electrons from MQ - 1 continually without the coupled proton transfer reactions. Because of ΔG 0 2b 0, ΔG 0 3b 0 and ΔG 0 4b 0, the corresponding PT_ET reactions could take place along with reactions (2b), (3b) and (4b) sequentially; (2) on the gaseous condition, the first and second transferred protons (H +(1) and H +(2)) from the surrounding amino acid residues or water molecules will combine with the oxygen No.7 and oxygen No.8 of UQ 1, respectively. On the condition of protein surroundings (by SCRF model, ε =4.0), the results are converse but the energy difference between the combination of H +(1) and H +(2) with UQ - 1 is quite small. The difference of ΔG 0 values between the corresponding reactions in gaseous surroundings and the SCRF model is not significant; (3) the PT_ET reactions between MQ 1 - and UQ 1 - should be as follows: MQ 1 -+UQ 1→MQ 1+UQ 1 - (1) UQ 1 - ( O (7) )+H +( HisL 190)→UQ 1H(2b) ( Gas ) or UQ 1 - ( O (8) )+H +(H 2O)→UQ 1H (2b') ( SCRF ) or UQ 1 - ( O (8) )+H + ( ArgL 217)→UQ 1H(2b') ( SCRF ) MQ 1 -+UQ 1H→MQ 1+UQ 1H - (3b) ( Gas ) MQ 1 -+UQ 1H→MQ 1+UQ 1H -(3b') ( SCR F) UQ 1H -+H +(H 2O)→UQ 1H 2(4b) ( Gas ) or UQ 1H -+H + ( ArgL 217)→UQ 1H 2 (4b) ( Gas ) or UQ 1H -+H + ( HisL 190)→UQ 1H 2 (4b') ( SCRF )展开更多
The divergent behavior of C-H bond oxidations of aliphatic substrates compared to those of aromatic substrates shown in Gupta’s experiment was mechanistically studied herein by means of density functional theory calc...The divergent behavior of C-H bond oxidations of aliphatic substrates compared to those of aromatic substrates shown in Gupta’s experiment was mechanistically studied herein by means of density functional theory calculations.Our calculations reveal that such difference is caused by different reaction mechanisms between two kinds of substrates(the aliphatic cyclohexane,2,3-dimethylbutane and the aromatic toluene,ethylbenzene and cumene).For the aliphatic substrates,C-H oxidation by the oxidant Fe^(V)(O)(TAML)is a hydrogen atom transfer process;whereas for the aromatic substrates,C-H oxidation is a proton-coupled electron transfer(PCET)process with a proton transfer character on the transition state,that is,a proton-coupled electron transfer process holding a proton transfer-like transition state(PCET(PT)).This difference is caused by the strongπ-πinteractions between the tetra-anionic TAML ring and the phenyl ring of the aromatic substrates,which has a“pull”effect to make the electron transfer from substrates to the Fe=O moiety inefficient.展开更多
The development of non‐precious metal catalysts that facilitate the oxygen evolution reaction(OER)is important for the widespread application of hydrogen production by water splitting.Various perovskite oxides have b...The development of non‐precious metal catalysts that facilitate the oxygen evolution reaction(OER)is important for the widespread application of hydrogen production by water splitting.Various perovskite oxides have been employed as active OER catalysts,however,the underlying mechanism that occurs at the catalyst‐electrolyte interface is still not well understood,prohibiting the design and preparation of advanced OER catalysts.Here,we report a systematic investigation into the effect of proton dynamics on the catalyst‐electrolyte interfaces of four perovskite catalysts:La_(0.5)Sr_(0.5)CoO_(3‐δ)(LSCO),LaCoO_(3),LaFeO_(3),and LaNiO_(3).The pH‐dependent OER activities,H/D kinetic isotope effect,and surface functionalization with phosphate anion groups were investigated to elucidate the role of proton dynamics in the rate‐limiting steps of the OER.For oxides with small charge‐transfer energies,such as LSCO and LaNiO_(3),non‐concerted proton‐coupled electron transfer steps are involved in the OER,and the activity is strongly controlled by the proton dynamics on the catalyst surface.The results demonstrate the important role of interfacial proton transfer in the OER mechanism,and suggest that proton dynamics at the interface should carefully be considered in the design of future high‐performance catalysts.展开更多
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。
文摘质子耦合电子转移(Proton-Coupled Electron Transfer,PCET)反应是生物和化学的重要过程,它与光合作用、呼吸过程、能量转化和存储,以及制备清洁能源材料等过程紧密相关。界面上的质子耦合电子转移反应是近年来的研究热点之一,本文对该领域进行了简要综述,主要介绍了发生在液/液界面和固/液界面上的质子耦合电子转移反应的研究进展。
文摘The mechanism of the proton_transfer_coupled electron transfer (PT_ET) reactions between the menaquinone Q A (MQ 1) and ubiquinone Q B (UQ 1) in the bacterial photosynthetic reaction center of Rhodopseudomona viridis was studied by using the B3LYP/6_31G(d) method. The changes of standard Gibbs free energy ΔG 0 of all possible reactions followed the ET reaction (1) were calculated. The results indicated that: (1) according to the ΔG 0 values of corresponding reactions, UQ 1 could not accept two electrons from MQ - 1 continually without the coupled proton transfer reactions. Because of ΔG 0 2b 0, ΔG 0 3b 0 and ΔG 0 4b 0, the corresponding PT_ET reactions could take place along with reactions (2b), (3b) and (4b) sequentially; (2) on the gaseous condition, the first and second transferred protons (H +(1) and H +(2)) from the surrounding amino acid residues or water molecules will combine with the oxygen No.7 and oxygen No.8 of UQ 1, respectively. On the condition of protein surroundings (by SCRF model, ε =4.0), the results are converse but the energy difference between the combination of H +(1) and H +(2) with UQ - 1 is quite small. The difference of ΔG 0 values between the corresponding reactions in gaseous surroundings and the SCRF model is not significant; (3) the PT_ET reactions between MQ 1 - and UQ 1 - should be as follows: MQ 1 -+UQ 1→MQ 1+UQ 1 - (1) UQ 1 - ( O (7) )+H +( HisL 190)→UQ 1H(2b) ( Gas ) or UQ 1 - ( O (8) )+H +(H 2O)→UQ 1H (2b') ( SCRF ) or UQ 1 - ( O (8) )+H + ( ArgL 217)→UQ 1H(2b') ( SCRF ) MQ 1 -+UQ 1H→MQ 1+UQ 1H - (3b) ( Gas ) MQ 1 -+UQ 1H→MQ 1+UQ 1H -(3b') ( SCR F) UQ 1H -+H +(H 2O)→UQ 1H 2(4b) ( Gas ) or UQ 1H -+H + ( ArgL 217)→UQ 1H 2 (4b) ( Gas ) or UQ 1H -+H + ( HisL 190)→UQ 1H 2 (4b') ( SCRF )
基金supported by the National Natural Science Foundation of China(No.21806018 and No.21873052)the Fundamental Research Funds for the Central Universities(DUT20RC(4)002)+1 种基金Scientific Research Grant of Ningbo University(No.215-432000282)Ningbo Top Talent Project(No.215-432094250)。
文摘The divergent behavior of C-H bond oxidations of aliphatic substrates compared to those of aromatic substrates shown in Gupta’s experiment was mechanistically studied herein by means of density functional theory calculations.Our calculations reveal that such difference is caused by different reaction mechanisms between two kinds of substrates(the aliphatic cyclohexane,2,3-dimethylbutane and the aromatic toluene,ethylbenzene and cumene).For the aliphatic substrates,C-H oxidation by the oxidant Fe^(V)(O)(TAML)is a hydrogen atom transfer process;whereas for the aromatic substrates,C-H oxidation is a proton-coupled electron transfer(PCET)process with a proton transfer character on the transition state,that is,a proton-coupled electron transfer process holding a proton transfer-like transition state(PCET(PT)).This difference is caused by the strongπ-πinteractions between the tetra-anionic TAML ring and the phenyl ring of the aromatic substrates,which has a“pull”effect to make the electron transfer from substrates to the Fe=O moiety inefficient.
文摘The development of non‐precious metal catalysts that facilitate the oxygen evolution reaction(OER)is important for the widespread application of hydrogen production by water splitting.Various perovskite oxides have been employed as active OER catalysts,however,the underlying mechanism that occurs at the catalyst‐electrolyte interface is still not well understood,prohibiting the design and preparation of advanced OER catalysts.Here,we report a systematic investigation into the effect of proton dynamics on the catalyst‐electrolyte interfaces of four perovskite catalysts:La_(0.5)Sr_(0.5)CoO_(3‐δ)(LSCO),LaCoO_(3),LaFeO_(3),and LaNiO_(3).The pH‐dependent OER activities,H/D kinetic isotope effect,and surface functionalization with phosphate anion groups were investigated to elucidate the role of proton dynamics in the rate‐limiting steps of the OER.For oxides with small charge‐transfer energies,such as LSCO and LaNiO_(3),non‐concerted proton‐coupled electron transfer steps are involved in the OER,and the activity is strongly controlled by the proton dynamics on the catalyst surface.The results demonstrate the important role of interfacial proton transfer in the OER mechanism,and suggest that proton dynamics at the interface should carefully be considered in the design of future high‐performance catalysts.
