Pt-Au/CNT@TiO2作为甲醇燃料电池的高活性阳极催化剂

以TiO2包覆的多壁碳纳米管(CNT@TiO2)为载体,Pt和Au为活性物质,采用沉积紫外光催化还原法制备出高活性的甲醇阳极电催化剂Pt-Au/CNT@TiO2,并采用X射线衍射、透射电镜和X射线光电子能谱对催化剂样品的物化特征进行表征.催化剂的抗毒性能用循环伏安和交流阻抗测试来表征.结果表明,粒径为2～3nm的Pt-...

Pt-Au/CNT@TiO_2 as a High-Performance Anode Catalyst for Direct Methanol Fuel Cells

Multi-walled carbon nanotubes (CNT) modified using TiO₂ nanoparticles (CNT@TiO₂) were prepared. Then, Pt-Au/CNT@TiO₂ catalysts were prepared by a deposition-UV-photoreduction method for direct methanol fuel cells. The physico-chemical properties of the catalysts were characterized by X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The catalytic performance was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy. The Pt-Au nanoparticles were found to be uniformly deposited onto the CNT@TiO₂ support and had diameters of 2–3 nm. Compared with the Pt-Au/CNT catalyst that was made using a general chemical method, Pt-Au/CNT@TiO₂ exhibits higher CO-tolerance for the following reasons. Firstly, the strong interaction between the Pt-Au alloy and TiO₂ leads to an increase in electron density on the metallic Pt-Au, which transfers electrons to the π_CO^* orbital of CO and weakens C–O binding while the oxidation overpotential is lowered. Secondly, the high-valence Ti ions dissociate water to form OH_ad (ad: adsorbed) species, which then reacts with the strongly bound CO_ad on the Pt surface to form CO₂.