Au-Containing Alloy Electrocatalysts for the Methanol Oxidation Reaction in Direct Methanol Fuel Cells: Recent Advances and Future Perspectives

Direct methanol fuel cells (DMFCs), as efficient and environmentally friendly energy conversion devices, have great prospects in portable power and distributed power generation. However, their commercialization is severely hindered by the sluggish kinetics of the anodic methanol oxidation reaction (MOR) and the susceptibility of conventional platinum (Pt)-based catalysts to poisoning by the intermediate carbon monoxide (CO), which leads to a sharp decline in both activity and stability. Gold (Au)-containing alloy electrocatalyst have emerged as one of the key material systems for overcoming these challenges, thanks to their unique electronic structure, exceptional resistance to CO poisoning, and tunable catalytic properties. This review systematically summarizes the latest research advances on Au-containing alloy electrocatalyst for MOR. We discussed the mechanisms of introducing Au to enhance catalytic performance through electronic effects (d-band center modulation), synergistic effects, and changing reaction pathways (from the "CO pathway" to the "formate pathway"). In addition, representative catalyst systems were summarized, including PtAu, PdAu, and other multi-component alloys, with a focus on the structure-activity relationship between their nanostructure design (such as bimetallic structures, nanowires, porous structures, and single atom alloys) and the catalytic performance. The MOR mechanism and electrocatalytic performance improvement and application are systemically elucidated by precise composition control, advanced nanostructure engineering, carrier modification, as well as theoretical calculations and in-situ characterization techniques ( in-situ infrared spectroscopy, XAFS, XPS, etc.). The current challenges of Au-containing alloy electro catalyst were also analyzed, such as balancing activity and stability, and achieving a deeper understanding of the mechanisms. Finally, future development directions were outlined, including atomic precise synthesis (such as single atom or cluster catalysts), multi field coupled catalysis (photo electrochemical or thermoelectric chemical synergistic effects), machine learning assisted catalyst design, and engineering research for practical DMFC equipment applications. This review aims to provide comprehensive insights and guidance for the rational design of high-performance, highly stable, and low-cost catalysts for DMFCs.