The synergistic catalysis of heterojunction electrocatalysts for the multi-step process in hydrogen evolution reaction(HER)is a promising approach to enhance the kinetics of alkaline HER.Herein,we proposed a strategy ...The synergistic catalysis of heterojunction electrocatalysts for the multi-step process in hydrogen evolution reaction(HER)is a promising approach to enhance the kinetics of alkaline HER.Herein,we proposed a strategy to form nanoscale Ni/NiO heterojunction porous graphitic carbon composites(Ni/NiO-PGC)by reduction-pyrolysis of the preformed Ni-metal-organic framework(MOF)under H2/N2 atmosphere.Benefiting from low electron transfer resistance,increased number of active sites,and unique hierarchical micro-mesoporous structure,the optimized Ni/NiO-PGC_(10-1-400)exhibited excellent electrocatalytic performance and robust stability for alkaline HER(η10=30 mV,65 h).Density functional theory(DFT)studies revealed that the redistribution of electrons at the Ni/NiO interface enables the NiO phase to easily initiate the dissociation of alkaline H_(2)O,and shifts down the d-band center of Ni and optimizes the H*adsorption-desorption process of Ni,thereby leading to extremely high HER activity.This work contributes to a further understanding of the synergistic promotion of the multi-step HER processes by heterojunction electrocatalysts.展开更多
Heterojunction nanocomposite electrocatalysts with porous structures and large specific surface areas show great potential in improving their intrinsic activity and the number of accessible active sites for oxygen evo...Heterojunction nanocomposite electrocatalysts with porous structures and large specific surface areas show great potential in improving their intrinsic activity and the number of accessible active sites for oxygen evolution reaction(OER).Herein,we describe an“exchanging sulfur for oxygen”protocol to fabricate a porous molybdate-based heterojunction electrocatalyst,Fe2(MoO4)3/CoMoO4,utilizing a sulfur-rich reagent,ammonium tetrathiomolybdate((NH4)2MoS4).During the calcination of the solid product formed from(NH4)2MoS4 and CoCl2/FeCl3,the sulfur atoms of MoS42-are oxidized into the acidic SO_(2)gas plus HCl and NH3 gases evolved in the system,which greatly facilitates the formation of macro/mesopores of the molybdate-based nanomaterial.It exhibits excellent electrocatalytic OER performance in alkaline media and only requires a low overpotential of 244 mV at a current density of 10 mA·cm^(-2) with outstanding durability.Experimental exami-nation and theoretical calculations reveal that its uniform interparticle porous structure enhances spatial connectivity and electrode–electrolyte contact,while strong electronic interactions at the heterointerface boost electrocatalytic activity.The phase combination increases interface electron concentration,accelerates charge transfer,and lowers free energy.This work provides a new strategy to construct the porous molybdate-based heterostructure electrocatalyst for remarkably boosting the OER performance.展开更多
Metal-organic frameworks possessing relatively large pores,high surface areas,and unsaturated metal sites are attractive materials for use as electrocatalysts in the reduction of N_(2)to NH_(3).In this work,a MIL-101(...Metal-organic frameworks possessing relatively large pores,high surface areas,and unsaturated metal sites are attractive materials for use as electrocatalysts in the reduction of N_(2)to NH_(3).In this work,a MIL-101(Fe)/MoS_(3)hybrid catalyst,prepared by using a precursor-transformation strategy,is shown to be an effective electrocatalyst for the N_(2)reduction reaction(NRR).Under solvothermal conditions,micro-sized octahedral MIL-101(Fe)precursors are converted into ultra-small nanodots,while amorphous MoS_(3)derived from(NH_(4))_(2)MoS_(4)provides a surface suitable for anchoring the MIL-101(Fe)nanodots.The asprepared composite exhibits excellent electrocatalytic activity and durability for the NRR with a Faraday efficiency of 36.71%and an NH_(3)yield of 25.7μg h^(-1)mg_(cat)^(-1)at-0.1 V vs.RHE in 0.1 M HCl.The results show that the dispersion and adherence of MIL-101(Fe)nanodots on amorphous MoS_(3)improves the exposure of active centers and aids mass transfer,resulting in greatly enhanced catalytic activity and stability.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22271203,21773163,and 22001021)the State Key Laboratory of Organometallic Chemistry of Shanghai Institute of Organic Chemistry(No.KF2021005)+2 种基金the Natural Science Foundation of Jiangsu Province(No.BK20201048)the Natural Science Research Project of Higher Education Institutions in Jiangsu Province(No.20KJB150008)the Collaborative Innovation Center of Suzhou Nano Science and Technology,the Priority Academic Program Development of Jiangsu Higher Education Institutions,and the Project of Scientific and Technologic Infrastructure of Suzhou(No.SZS201905).
文摘The synergistic catalysis of heterojunction electrocatalysts for the multi-step process in hydrogen evolution reaction(HER)is a promising approach to enhance the kinetics of alkaline HER.Herein,we proposed a strategy to form nanoscale Ni/NiO heterojunction porous graphitic carbon composites(Ni/NiO-PGC)by reduction-pyrolysis of the preformed Ni-metal-organic framework(MOF)under H2/N2 atmosphere.Benefiting from low electron transfer resistance,increased number of active sites,and unique hierarchical micro-mesoporous structure,the optimized Ni/NiO-PGC_(10-1-400)exhibited excellent electrocatalytic performance and robust stability for alkaline HER(η10=30 mV,65 h).Density functional theory(DFT)studies revealed that the redistribution of electrons at the Ni/NiO interface enables the NiO phase to easily initiate the dissociation of alkaline H_(2)O,and shifts down the d-band center of Ni and optimizes the H*adsorption-desorption process of Ni,thereby leading to extremely high HER activity.This work contributes to a further understanding of the synergistic promotion of the multi-step HER processes by heterojunction electrocatalysts.
基金the National Natural Science Foundation of China(Nos.U24A20507,22271203,22001021, 22478152)the State Key Laboratory of Organometallic Chemistry of Shanghai Institute of Organic Chemistry(No.2024KF005)Open Research Fund of State Key Laboratory of Coordination Chemistry,School of Chemistry and Chemical Engineering,Nanjing University,the Collaborative Innovation Center of Suzhou Nano Science and Technology,and the Project of Scientific and Technologic Infrastructure of Suzhou(No.SZS201905).
文摘Heterojunction nanocomposite electrocatalysts with porous structures and large specific surface areas show great potential in improving their intrinsic activity and the number of accessible active sites for oxygen evolution reaction(OER).Herein,we describe an“exchanging sulfur for oxygen”protocol to fabricate a porous molybdate-based heterojunction electrocatalyst,Fe2(MoO4)3/CoMoO4,utilizing a sulfur-rich reagent,ammonium tetrathiomolybdate((NH4)2MoS4).During the calcination of the solid product formed from(NH4)2MoS4 and CoCl2/FeCl3,the sulfur atoms of MoS42-are oxidized into the acidic SO_(2)gas plus HCl and NH3 gases evolved in the system,which greatly facilitates the formation of macro/mesopores of the molybdate-based nanomaterial.It exhibits excellent electrocatalytic OER performance in alkaline media and only requires a low overpotential of 244 mV at a current density of 10 mA·cm^(-2) with outstanding durability.Experimental exami-nation and theoretical calculations reveal that its uniform interparticle porous structure enhances spatial connectivity and electrode–electrolyte contact,while strong electronic interactions at the heterointerface boost electrocatalytic activity.The phase combination increases interface electron concentration,accelerates charge transfer,and lowers free energy.This work provides a new strategy to construct the porous molybdate-based heterostructure electrocatalyst for remarkably boosting the OER performance.
基金supported by the National Natural Science Foundation of China(21773163,21531006,22001021)the State Key Laboratory of Organometallic Chemistry of Shanghai Institute of Organic Chemistry(KF2021005)+3 种基金Natural Science Foundation of Jiangsu Province(BK20201048)Natural Science Research Project of Higher Education Institutions in Jiangsu Province(20KJB150008)Collaborative Innovation Center of Suzhou Nano Science and Technologythe Project of Scientific and Technologic Infrastructure of Suzhou(SZS201905)。
文摘Metal-organic frameworks possessing relatively large pores,high surface areas,and unsaturated metal sites are attractive materials for use as electrocatalysts in the reduction of N_(2)to NH_(3).In this work,a MIL-101(Fe)/MoS_(3)hybrid catalyst,prepared by using a precursor-transformation strategy,is shown to be an effective electrocatalyst for the N_(2)reduction reaction(NRR).Under solvothermal conditions,micro-sized octahedral MIL-101(Fe)precursors are converted into ultra-small nanodots,while amorphous MoS_(3)derived from(NH_(4))_(2)MoS_(4)provides a surface suitable for anchoring the MIL-101(Fe)nanodots.The asprepared composite exhibits excellent electrocatalytic activity and durability for the NRR with a Faraday efficiency of 36.71%and an NH_(3)yield of 25.7μg h^(-1)mg_(cat)^(-1)at-0.1 V vs.RHE in 0.1 M HCl.The results show that the dispersion and adherence of MIL-101(Fe)nanodots on amorphous MoS_(3)improves the exposure of active centers and aids mass transfer,resulting in greatly enhanced catalytic activity and stability.
