摘要
Development of cost-effective,active and durable electrocatalysts for overall water splitting is still a huge challenge.Herein,we have constructed one-dimensional(1D)cobalt sulfide and vanadium sulfide heterojunction nanowires arranged on carbon cloth(Co_(9)S_(8)-V_(3)S_(4)/CC)as bifunctional electrocatalysts for the efficient overall water splitting.The 1D wire-structured Co_(9)S_(8)-V_(3)S_(4)heterojunctions possess large surface area,plentiful active sites and rapid transport of electrons/reactants and the release of gas.Importantly,the electron transfer from Co9S8 to V3S4 occurs at the interface due to the strong electronic coupling effect in Co_(9)S_(8)-V_(3)S_(4)heterojunction,in which the electron-attracting V3S4(V2^(+))optimizes the adsorption of H*active species for hydrogen evolution reaction(HER),while the electron-losing Co9S8(Co3+)responds to the enhancement of oxygen evolution reaction(OER)activity.Co_(9)S_(8)-V_(3)S_(4)/CC exhibits low overpotentials of 85 and 232 mV at 10 mA cm^(−2)and small Tafel slopes of 51 and 59 mV dec^(−1)for HER and OER,respectively.Especially,the electrolyzer with Co_(9)S_(8)-V_(3)S_(4)/CC as both the anode and cathode requires low onset voltage of 1.35 V and cell voltage of 1.53 V at 10 mA cm^(−2)and exhibits high Faradaic efficiencies and robust stability.It can be driven by a solar cell(1.53 V)for continuous production of hydrogen and oxygen.This study highlights the design of 1D sulfide heterojunction in pursuit of highly efficient electrocatalysts for overall water splitting.
发展低成本、高活性和稳定的电催化分解水电催化剂,仍然是一项巨大的挑战.本研究工作中,我们构建了一种在碳布基底上生长的一维硫化钴和硫化钒异质结纳米线(Co_(9)S_(8)-V_(3)S_(4)/CC)作为双功能电催化剂用于高效全解水.一维线状结构的Co_(9)S_(8)-V_(3)S_(4)/CC具有大比表面积、丰富的活性位点和快速的质子/电子转移能力以及释放气体的能力.更重要的是,由于Co_(9)S_(8)-V_(3)S_(4)异质结具有强电子耦合效应,在界面处,Co9S8的电子向V3S4转移,即V3S4(V2^(+))吸引电子,有利于析氢反应中的H*活性位点的吸附,Co9S8(Co^(3+))失去电子,有利于提高析氧反应催化活性.在10 mA cm^(−2)的电流密度下,Co_(9)S_(8)-V_(3)S_(4)/CC催化HER、OER的过电位分别是85和232 mV;Tafel斜率分别是51和59 mV dec^(−1).以Co_(9)S_(8)-V_(3)S_(4)/CC分别作为阳极和阴极用于全解水,起始电压仅为1.35 V,达到10 mA cm^(−2)的电流密度所需电压仅为1.53 V,且具有高法拉第效率和高稳定性.此装置可被太阳能电池(1.53 V)驱动连续产生H2和O2.这项工作提出了一种设计用于高效全解水的一维硫化物异质结电催化剂的新方法.
基金
supported by the National Key R&D Program of China (2018YFB1502401)
the National Natural Science Foundation of China (21631004, 21805073, 2161055 and 21901064)
the Natural Science Foundation of Heilongjiang Province (QC2018014)
the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province (UNPYSCT-2017123 and UNPYSCT-2017118)
the Basic Research Fund of Heilongjiang University in Heilongjiang Province (RCYJTD201801)
Heilongjiang University Excellent Youth Foundation
