WC/C制备条件对甲醇电氧化特性的影响研究

Study of the Effect of W/C Preparation Conditions on Methanol Electro Oxidation Character

以钨酸铵为前躯体,采用程序升温控制还原法(TPR)制备了WC/C纳米颗粒,在碳载体存在的情况下,研究了钨源前躯体碳化过程中CH4与H2流量比对单一WC晶相以及Pt/WC/C电催化氧化甲醇性能的影响。XRD测试结果发现:仅在CH4:H2流量比为2时可获得单一WC多晶,其平均粒径为11.3 nm。循环伏安实验结果证实:10wt%Pt-10wt%WC/C电催化氧化CH3OH的比质量活性达到875 mA.mg-1,远远高于10wt%Pt/C的658 mA.mg-1,且起始氧化电位负移80 mV。计时电流法实验表明Pt/WC/C在酸性介值中稳定性高于Pt/C催化剂。

Tungsten carbide nano - particles were prepared by temperature programmed reduction method with ammo- nium tungstate as precursor. Single component tungsten carbide was obtained by controlling the flow ratio of methane to hydrogen in the process of carbonization, and the effect of Pt/WC/C was investigated on methanol electro oxidation char- acter. The XRD test result showed that the pure WC particles were obtained only in the condition of CH4 and H2 flow rate equal to 2, and the average particle diameter of WC was 11.3 nm. It was founded from cyclic vohammograms that the spe- -I cific electrochemical activity of 10wt% Pt- 10wt% WC/C to the electro- oxidation of CH3OH reached to 875 mA ~ mg Pt, much higher than that of 10wt% Pt/C（of 658 mA · mg^-1 Pt） , and the onset oxidation potential was 350 mV vs SCE and was negatively shifted 80 mV, compared to the later one. The chronoamperometry indicated that Pt/WC/C had better stability than Pt/C in the acidic medium.