Design and Optimization of Anode Catalysts for Direct Ethanol Fuel Cells: Advances and Challenges in C-C Bond Activation and Selective Modulation of the C1 Pathway

Direct ethanol fuel cells (DEFCs) are a promising alternative to conventional energy sources, offering high energy density, environmental sustainability, and operational safety. Compared to methanol fuel cells, DEFCs exhibit lower toxicity and a more mature preparation process. Unlike hydrogen fuel cells, DEFCs provide superior storage and transport feasibility, as well as cost-effectiveness, significantly enhancing their commercial viability. However, the stable C–C bond in ethanol creates a high activation energy barrier, often resulting in incomplete electrooxidation. Current commercial platinum (Pt)- and palladium (Pd)-based catalysts demonstrate low C–C bond cleavage efficiency (<7.5%), severely limiting DEFC energy output and power density. Furthermore, high catalyst costs and insufficient activity impede large-scale commercialization. Recent advances in DEFC anode catalyst design have focused on optimizing material composition and elucidating catalytic mechanisms. This review systematically examines developments in ethanol electrooxidation catalysts over the past five years, ighlighting strategies to improve C1 pathway selectivity and C–C bond activation. Key approaches, such as alloying, nanostructure engineering, and interfacial synergy effects, are discussed alongside their mechanistic implications. Finally, we outline current challenges and future prospects for DEFC commercialization.