The high cost and low reserves of noble metals greatly hinder their practical applications in new energy production and conversion.The exploration of cost-effective alternative electrocatalysts with the ability to dri...The high cost and low reserves of noble metals greatly hinder their practical applications in new energy production and conversion.The exploration of cost-effective alternative electrocatalysts with the ability to drive hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is extremely significant to promote overall water splitting.Herein,ultrathin CoSe2/CNTs nanocomposites have been synthesized by a facile two-step method,where the ultrathin Co-MOF(metal organic-framework)decorated with cable-like carbon nanotubes(CNTs)(Co-MOF/CNTs)was initially fabricated,and followed a lowtemperature selenization process.The ultrathin CoSe2 nanosheets as well as the superior conductivity of CNTs synergistically resulted in abundant active sites and enhanced conductivity to boost the electrocatalytic activity.The as-prepared CoSe2/CNTs electrocatalysts exhibited an overpotential of190 mV and 300 mV vs.reversible hydrogen electrode(RHE)at a current density of 10 mA/cm^(2) for the HER and OER in alkaline solution,respectively,and demonstrated superior durability.Furthermore,the as-prepared bifunctional CoSe2/CNTs electrocatalysts can act as cathode and anode in an electrolyzer,showing a cell voltage of 1.75 V at 10 mA/cm^(2) for overall water splitting.展开更多
Pt-based ultrathin nanowires (NWs) are considered as one of the most intriguing catalysts for fuel cells.However,the delicate controllability of surface structure of ultrathin NWs to regulate their catalytic performan...Pt-based ultrathin nanowires (NWs) are considered as one of the most intriguing catalysts for fuel cells.However,the delicate controllability of surface structure of ultrathin NWs to regulate their catalytic performances is still a challenge.Here,two kinds of one-nanometer-thick Pt-based NWs with smooth surfaces (S-NWs) and rough surfaces (R-NWs) are demonstrated,in which the combined use of hexadecyltrimethylammonium bromide and oleylamine plays an essential role,as they could form soft-templates to direct the growth of NWs.Due to its high-density of low-coordinated sites on the surface,Pt-based R-NWs exhibit higher oxygen reduction reaction (ORR) activities but lower stabilities than corresponding S-NWs.Notably,Pt0.78Ni0.22 R-NWs possess the highest mass activity (1.07 A-mgpt^-1) and specific activity (1.02 mA·cm^-2) among all Pt-based NWs.After 10,000 sweeping cycles,the mass activity still exhibits 5.7-fold enhancement compared to the corresponding commercial Pt/C.This work presents a new approach to delicately control the surface structure of ultrathin Pt-based NWs as advanced ORR catalysts.展开更多
基金the financial support by the National Natural Science Foundation of China(No.21771137)the Key Project of Natural Science Foundation of Tianjin(No.18JCZDJC97200)+1 种基金the Training Project of Innovation Team of Colleges and Universities in Tianjin(No.TD13-5020)the start-up fund of Qilu University of Technology,Shandong Academy of Sciences。
文摘The high cost and low reserves of noble metals greatly hinder their practical applications in new energy production and conversion.The exploration of cost-effective alternative electrocatalysts with the ability to drive hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is extremely significant to promote overall water splitting.Herein,ultrathin CoSe2/CNTs nanocomposites have been synthesized by a facile two-step method,where the ultrathin Co-MOF(metal organic-framework)decorated with cable-like carbon nanotubes(CNTs)(Co-MOF/CNTs)was initially fabricated,and followed a lowtemperature selenization process.The ultrathin CoSe2 nanosheets as well as the superior conductivity of CNTs synergistically resulted in abundant active sites and enhanced conductivity to boost the electrocatalytic activity.The as-prepared CoSe2/CNTs electrocatalysts exhibited an overpotential of190 mV and 300 mV vs.reversible hydrogen electrode(RHE)at a current density of 10 mA/cm^(2) for the HER and OER in alkaline solution,respectively,and demonstrated superior durability.Furthermore,the as-prepared bifunctional CoSe2/CNTs electrocatalysts can act as cathode and anode in an electrolyzer,showing a cell voltage of 1.75 V at 10 mA/cm^(2) for overall water splitting.
基金This work was supported by the National Natural Science Foundation of China(NSFC)(No.51772142)Shenzhen Science and Technology Innovation Committee(Nos.KQJSCX20170328155428476 and KQTD2016053019134356)+1 种基金Development and Reform Commission of Shenzhen Municipality(Novel Nanomaterial Discipline Construction Plan)the China Postdoctoral Science Foundation(No.2018M641633).
文摘Pt-based ultrathin nanowires (NWs) are considered as one of the most intriguing catalysts for fuel cells.However,the delicate controllability of surface structure of ultrathin NWs to regulate their catalytic performances is still a challenge.Here,two kinds of one-nanometer-thick Pt-based NWs with smooth surfaces (S-NWs) and rough surfaces (R-NWs) are demonstrated,in which the combined use of hexadecyltrimethylammonium bromide and oleylamine plays an essential role,as they could form soft-templates to direct the growth of NWs.Due to its high-density of low-coordinated sites on the surface,Pt-based R-NWs exhibit higher oxygen reduction reaction (ORR) activities but lower stabilities than corresponding S-NWs.Notably,Pt0.78Ni0.22 R-NWs possess the highest mass activity (1.07 A-mgpt^-1) and specific activity (1.02 mA·cm^-2) among all Pt-based NWs.After 10,000 sweeping cycles,the mass activity still exhibits 5.7-fold enhancement compared to the corresponding commercial Pt/C.This work presents a new approach to delicately control the surface structure of ultrathin Pt-based NWs as advanced ORR catalysts.
