直接甲醇燃料电池(DMFC)阳极过渡金属基催化剂的研究进展

Research progress in anode transition metal-based catalysts for direct methanol fuel cell

  • 摘要: 发展可替代能源对缓解全球能源问题具有重要意义。直接甲醇燃料电池(DMFC)因其工作温度低、能量密度高以及低污染物排放特性正逐渐成为最有发展前景的便携式能源技术之一。目前,其商业化进程主要取决于阳极甲醇氧化反应(MOR)的动力学快慢。贵金属作为最常用的阳极催化剂得到了广泛的研究,但是其稀缺性以及易受COads中间产物中毒影响限制了其应用。考虑到以上问题,具有优异抗中毒能力的低Pt或者非Pt纳米催化剂的设计和研发变得十分重要。本文从DMFC阳极电催化原理出发,总结了过渡金属基催化剂(过渡金属−贵金属催化剂、过渡金属催化剂以及自支撑催化剂)在MOR中的研究进展。重点强调了纳米催化剂的组成成分、多孔结构、高指数面、晶体缺陷以及顶点增强效应等对其电化学性能的影响。最后,展望了过渡金属基电催化剂在DMFC中所面临的机遇和挑战。

     

    Abstract: The development of alternative energy resources is of great significance to alleviate the global energy issue. The direct methanol fuel cell (DMFC) is gradually becoming one of the most promising portable energy technologies due to the merits of low operating temperature, high energy density, and low pollutant emission. Currently, its commercialization process mainly depends on the kinetics of the anodic methanol oxidation reaction (MOR). Noble metals have been widely studied as the most commonly used anode catalysts. However, high prices and limited reserves have severely hindered their further development. In addition, the active surface of Pt is susceptible to the poison of COads intermediate products, leading to the rapid loss of the catalytic activity due to blocked Pt sites. Considering the above problems, the design and development of low Pt or non-Pt nanocatalysts with an excellent antipoisoning ability have become very important. Transition metals have been widely used as promising substitutes for noble metal catalysts because of their abundant reserves, low price, and high catalytic activity. Among the transition metals studied, Ni, Cu, and Co have attracted sustained attention because of their high corrosion resistance. Owing to the ligand effect and synergistic effect, the addition of transition metals can effectively weaken the adsorption of COads intermediates on Pt sites. At the same time, non-noble transition metals are easy to form MOOH active species, which promote the oxidation of COads intermediates. Besides, methanol electrooxidation performance is closely related to the shape, structure, and composition of transition metals. From the principle of DMFC anode electrocatalysis, this review summarized the research progress of transition metal-based catalysts (transition metal-noble metal catalysts, transition metal catalysts, and self-supporting catalysts) in MOR. More importantly, the effects of the nanocatalyst composition, porous structure, high-index surface, crystal defects, and vertex enhancement on its electrochemical properties were emphasized. Finally, opportunities and challenges faced by transition metal-based electrocatalysts in DMFC were discussed.

     

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