碳化钨负载纳米铂催化剂的制备及其析氢催化性能

以喷雾干燥处理的偏钨酸铵为前驱体, 采用CH4/H2为还原碳化气氛, 利用固定床气固反应法制备了具有介孔结构的碳化钨(WC)粉体. 然后通过浸渍法制备了Pt/WC粉末催化剂. 通过XRD和SEM等测试手段对Pt/WC粉末样品进行了表征, 结果表明, Pt颗粒平均直径约为13.5 nm, 且均匀分散在介孔结构WC载体上. 采用循环伏安和线性扫描等方法研究了酸性介质中Pt/WC粉末微电极对电化学析氢过程的电催化行为. 结果表明, 该电极对析氢反应具有很好的电催化活性和化学稳定性. 通过测试和计算, Pt/WC粉末微电极的Tafel方程中的a值为0.292 V, 属于低超电势析氢材料, 析氢交换电流密度为4.42 mA·cm-2, 与铂电极在同一个数量级上, 当超电势为250 mV时, 其析氢反应的活化能为26.20 kJ·mol-1.

Preparation of Tungsten Carbide-supported Nano Platinum Catalyst and Its Electrocatalytic Activity for Hydrogen Evolution

Using ammonium metatungstate (AMT) treated by spay drying as precursors, the tungsten carbides (WC) catalyst with meso-porosity was prepared by gas-solid reaction in the atmosphere of CH4/H2. The WC-supported nano platinum (Pt) catalyst was prepared by impregnation. SEM and XRD results showed that the average diameter of the Pt particles which were well dispersed on the surface of Pt/WC, was about 13.5 nm. The electro-catalytic properties and chemical stability of the Pt/WC powder microelectrode (PME) for the hydrogen evolution reaction in acid solution were investigated using the electrochemical techniques of cyclic voltammetry and linear sweep voltammetry. The results showed that the Pt/WC-PME exhibited an attractive catalytic activity in hydrogen evolution with parameter a in Tafel equation was 0.292 V, and the exchange current density of hydrogen evolution was 4.42 mA·cm-2. When the over-potential was 250 mV, the activation energy of hydrogen evolution was 26.20 kJ·mol-1.