Pt的氧化状态对甲醇氧化活性的影响

采用NaBH4还原法制备了XC-72碳黑负载的Pt电催化剂,并在化学还原后用H2O2处理部分催化剂以改变Pt的氧化状态,以期改善Pt活性中心上水的离解而提高催化活性.X射线光电子能谱结果表明,经H2O2处理的催化剂含有较多的氧化态Pt.通过循环伏安法和记时电流法考察了经处理和未经处理的催化剂在酸性条件下的甲醇氧化的催化...

Effect of Pt Oxidation State on Methanol Oxidation Activity

Pt catalysts supported on Vulcan XC-72 carbon were prepared by the NaBH₄ reduction of H₂PtCl₆ in the presence of a carbon support. One of the catalysts was deliberately treated with H₂O₂ after chemical reduction to alter the oxidation state of Pt and to promote methanol oxidation through more efficient water dissociation on the Pt sites. X-ray photoelectron spectroscopy confirmed that H₂O₂ treatment resulted in a more oxidized Pt catalyst. The electrooxidation of methanol over treated and untreated Pt catalysts in acidic solutions at room temperature was investigated by cyclic voltammetry and chronoamperometry. Despite their design, the more oxidized Pt catalysts could not supply active oxygen capable of removing the reaction-inhibiting CO-like reaction intermediates. As a result the catalytic activity was still largely dependent on the Pt oxidation state with the more “metallic” catalyst showing higher methanol oxidation activity and more CO tolerance.