直接气相还原法制备金属铱及其氧还原活性

Direct Gas Phase Reduction of Iridium and Its Catalytic Activity

摘要:

采用直接气相还原法制备了金属铱催化剂。通过X射线衍射 (XRD) 分析了金属铱的物相组成，采用循环伏安 (CV) 和线性电势扫描 (LSV) 等电化学手段评价了金属铱的电化学性能。XRD分析结果表明在氨气气氛中，氧化铱经400 ℃还原3 h能完全转化为金属铱单质。CV和LSV结果表明金属铱具有良好的氧还原电催化活性，且其氧还原起始电压可以达到0.51 V (vs. SCE)。从原子状态角度考虑，金属铱的d带空穴多于金属铂，最终导致金属铱的氧还原电催化活性低于金属铂，但金属铱具有与金属铂相似的氧还原电催化路径

Abstract:

Iridium catalyst was prepared by a direct gas phase reduction method. The phase composition of iridium was analyzed by X-ray diffraction, and the electrochemical performance was evaluated by cyclic voltammetry (CV) and linear scanning voltage (LSV). The result of XRD shows that iridium is transformed completely from iridium oxides after 400 °C reduction for 3 h under ammonia atmosphere. According to the result of CV and LSV, iridium possesses favorable electrocatalytic activity for oxygen reduction. The onset potential of iridium for oxygen reduction reaction (ORR) achieves 0.51 V (vs. SCE). From the viewpoint of atomic states, the number of d-band vacancy of iridium is more than that of platinum which leads to the lower electrocatalytic activity of iridium than that of platinum, but the two electrocatalysts have the similar electrocatalytic paths for ORR