MOF衍生CoP/C的制备、表征及电化学析氢性能

Preparation,characterization and electrochemical hydrogen evolution of MOF-derived CoP/C

采用类沸石咪唑酯骨架化合物ZIF-67(zeolitic imidazolate framework-67)和六水合硝酸钴为原料制备金属有机物框架材料(metal organic frameworks,MOF),经过高温煅烧及磷化,得到碳包覆磷化钴(CoP/C)粉体。用X射线衍射仪、扫描电镜及透射电镜对CoP/C粉末进行表征与分析,并进行电催化析氢实验。结果表明,高温煅烧后,ZIF-67的有机组分转化为导电炭骨架,钴离子转化为单质钴纳米颗粒嵌于炭骨架中,形成金属有机框架。经进一步磷化后,得到纯相CoP/C粉体。CoP/C粉末表现出良好的电化学析氢性能,其过电位为64mV,塔菲尔斜率为66mV/dec,历经15h电催化析氢后仍保持高催化活性。

Carbon-coated cobalt phosphide(CoP/C) powders were prepared by high temperature pre-annealing and further phosphating using Zeolitic Imidazolate Framework-67(ZIF-67) and Co(NO3)2·6 H2 O as precursor. CoP/C powders were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and transmission electron microscopy(TEM), and the electrocatalytic hydrogen evolution experiments were also carried out. The results show that after calcination at high temperature, the organic components of ZIF-67 are transformed into conductive carbon skeleton, and cobalt ions are transformed into elemental cobalt nanoparticles embedded in the carbon skeleton. After further phosphating, pure phase CoP/C powders are obtained. CoP/C powders exhibit good catalytic activity with an overpotential of 64 m V and a Tafel slope of 66 m V/dec, which maintains high catalytic activity after 15 h for electrocatalytic hydrogen evolution.