三维有序介孔镍铁磷化物的制备及电解水析氢性能研究

Preparation of three-dimensional ordered mesoporous nickel-iron phosphide and its hydrogen evolution performance in water electrolysis

利用三维SiO_(2)纳米球阵列作为介孔模板,通过高温磷化合成了不同镍与铁物质的量比的三维有序介孔镍铁磷化物(3DOM Ni_(X)Fe_(1-X)P);利用透射电子显微镜(TEM)、氮气吸脱附测试(BET)、X射线衍射(XRD)、X射线光电子能谱(XPS)等物理表征方法对所制备材料的形貌和结构进行分析,并通过电化学测试在0.5 mol/L H_(2)SO_(4)中系统评价了其电解水析氢(HER)性能。结果表明:3DOM Ni_(X)Fe_(1-X)P成功地反向复制了SiO_(2)模板的有序介孔结构,孔道之间排列整齐且相互连通;随着Fe含量的增加,3DOM Ni_(X)Fe_(1-X)P的HER性能呈现先升高后下降的趋势,在Ni与Fe物质的量比为7∶3时HER性能达到最优;当电流密度达到10 mA/cm^(2)时,3DOM Ni_(0.7)Fe_(0.3)P所需过电位为132 mV,Tafel斜率为59 mV/dec,并且具有良好的电化学稳定性。3DOM Ni_(0.7)Fe_(0.3)P优异的电催化HER性能可归结于三维有序介孔结构提供的高比表面积以及双金属有效结合引起的协同增强效应。

Three-dimensional ordered mesoporous Ni-Fe phosphides(3DOM Ni_(X)Fe_(1-X)P)with different molar ratios of nickel to iron have been synthesized by high temperature phosphating using three-dimensional SiO_(2)nanosphere arrays as mesoporous templates.The morphology and structure of the prepared materials were analyzed by transmission electron microscopy(TEM),nitrogen absorption and desorption measurements(BET),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).The hydrogen evolution reaction(HER)performance of the prepared materials was systematically evaluated by electrochemical testing in 0.5 mol/L H_(2)SO_(4).The results show that 3DOM Ni_(X)Fe_(1-X)P successfully replicates the ordered mesoporous structure of the SiO_(2)template in reverse,and the pores are neatly arranged and connected with each other.With increasing Fe content,the HER performance of 3DOM Ni_(X)Fe_(1-X)P first increased and then decreased,and the optimal HER performance was reached when the molar ratio of Ni to Fe was 7∶3.When the current density was 10 mA/cm^(2),the required overpotential of 3DOM Ni_(0.7)Fe_(0.3)P was 132 mV,the Tafel slope was 59 mV/dec,and the material showed good electrochemical stability.The excellent electrocatalytic performance of 3DOM Ni_(0.7)Fe_(0.3)P can be attributed to the high specific surface area provided by the three-dimensional ordered mesoporous structure and the synergistic enhancement effect caused by the effective combination of the two metals.