Balancing C- and O-species activation for enhanced synergistic electrooxidation of alcohols and formic acid on grain boundary-engineered PtPdNi alloy aerogels.

Direct liquid fuel cell offer high theoretical energy density, portability, and low environmental impact; however, commercialization remains hindered by challenges such as intermediate-induced catalyst poisoning, the high cost and scarcity of platinum, and inefficient CC bond cleavage during ethanol oxidation. To overcome these limitations, this study develops a grain boundary-rich PtPdNi ternary aerogel alloy as a high-performance catalyst for direct liquid fuel cell anodic reactions. Theoretical calculations indicate the engineered grain boundaries enhance active site density and modulate the catalyst's electronic structure, greatly expanded the adsorption energy range of CO* and OH*. Electrochemical diagnostics validate the catalyst's exceptional structural stability and durability attributed to the grain boundary architecture. Compared to PtPdNi single-crystalline counterpart without grain boundary, PtPdNi grain boundary-rich catalyst achieves specific activities 1.4-, 1.7-, and 2.5-fold higher for methanol, ethanol, and formic acid oxidation, respectively. Advanced in situ infrared data provide the analyses of the mechanism of small molecule electro-oxidation by grain boundaries in catalysts. This work introduces a grain boundary engineering strategy to elevate catalytic performance, providing critical insights into the design of robust direct liquid fuel cell catalysts.