基于钴基沸石咪唑酯骨架增强电催化硫离子氧化反应活性的研究

Cobalt-based zeolitic imidazolate framework as an efficient catalyst to enhanced the electrocatalytic performance for sulfion oxidation reaction

电解水是可持续绿色制氢的重要方法,但阳极缓慢的析氧反应(OER)严重阻碍电解水能量转化效率的提升,利用氧化电位较低的硫离子氧化反应(SOR)替代OER与阴极析氢反应耦合可以实现能耗的大幅降低。本文通过共沉淀法成功制备了一种钻基沸石咪唑酯骨架材料(ZIF-67),通过XRD、SEM、XPS测试手段对催化材料进行了物相分析,结果表明制备的ZIF-67催化材料由许多堆积在一起的立方体纳米颗粒组成。在三电极体系中对其进行SOR催化性能测试,将ZIF-67涂敷在泡沫镍基底上作为工作电极(ZIF-67/NF),ZIF-67/NF仅需0.361Vvs.RHE的电压就可以达到50mA·cm^(2)的电流密度,其电催化活性远优于Co(OH),/NF和NF。ZIF-67/NF还表现出最低的Tafel斜率(73mA·dec^(-1))和最小的电化学阻抗,并展现出良好的稳定性此外,对基于SOR的两电极耦合制氢体系的电化学性能进行了测试,发现所需施加电压远小于传统的全水解制氢系统,为超低能耗制氢提供一种切实可行的方案。

Water electrolysis is an important method for sustainable green hydrogen production,but the slow anodic oxygen evolution reaction(OER)severely hinders the improvement of the energy conversion efficiency of water electrolysis for hydrogen production.Using the sulfion oxidation reaction(SOR)with a lower oxidation potential instead of OER,coupled with the cathodic hydrogen evolution reaction,can significantly reduce energy consumption.In this work,a cobalt-based zeolitic imidazolate framework material(ZIF-67)was successfully prepared by the coprecipitation method.Phase analysis of the catalytic material was carried out by XRD,SEM,XPS and other testing methods,indicating that the prepared ZIF-67 catalytic material consists of many stacked cubic nanoparticles.The SOR catalytic performance of ZIF-67 was tested in a three-electrode system,with ZIF-67 coated on a nickel foam substrate as the working electrode(ZIF-67/NF).ZIF-67/NF only requires 0.36 V vs.RHE to achieve a current density of 50 mA.cm^(2),and its electrocatalytic activity is much superior to that of Co(OH)2/NF and NF.ZIF-67/NF also shows the lowest Tafel slope(73 mV·dec^(-1))and the smallest electrochemical impedance,and demonstrates good stability.In addition,the electrochemical performance of the two-electrode coupled hydrogen production system based on SOR was tested,and the required voltage was found to be much lower than that of the traditional full water electrolysis hydrogen production system,providing a feasible scheme for hydrogen production with ultra-low energy consumption.