碳化物
碳化钨
电化学
材料科学
过渡金属
循环伏安法
钨
无机化学
钼
电解质
钝化
金属
催化作用
化学
冶金
电极
物理化学
复合材料
有机化学
图层(电子)
作者
Mark C. Weidman,Daniel V. Esposito,Yeh-Chun Hsu,Jingguang G. Chen
标识
DOI:10.1016/j.jpowsour.2011.10.093
摘要
Transition metal carbides have shown potential for use in electrochemical applications as low-cost catalysts or catalyst support materials. In order to determine which transition metal carbides are suitable for specific electrochemical applications, it is necessary to determine their stability in electrolytic solutions of varying pH values. In this work we compare the stability of the most commonly used carbides: tungsten carbides (WC and W2C) and molybdenum carbide (Mo2C). Cyclic voltammetry (CV) is used to determine the onset of oxidation and the hydrogen evolution reaction (HER) at discrete pH values while chronopotentiometric (CP) titrations are used to create potential-pH ‘stability maps’, which designate the regions of stability, passivation, and oxidation. Based on the slopes of the boundaries between the regions of stability, information about the oxidation mechanisms is obtained through the Nernst equation, indicating key differences in the electrochemical behavior of each surface. WC exhibits enhanced resistance to surface oxidation in acidic solution and comparable stability in neutral/alkaline solution to Mo2C and W2C.
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