Electronic Structure Engineering of Pd–Cu Alloy Catalysts for Enhanced Methanol Electrooxidation

The widespread application of direct methanol fuel cells (DMFCs) is limited by the sluggish kinetics of the anodic reaction, the high cost of catalysts, and their susceptibility to poisoning. Pd-based catalysts are among the most promising anode materials for DMFCs; however, their sluggish methanol oxidation reaction (MOR) kinetics and poisoning resistance require further enhancement to meet practical demands. In this study, we accurately regulate the electronic structure of Pd by synthesizing a series of Pd-Cu/C alloy catalysts with precisely controlled Pd/Cu atomic ratios, thereby realizing the efficient and poison-resistant electrocatalyst for MOR. Theoretical calculations reveal that the electronic structure of Pd is modulated by controlling the incorporation of Cu, which weakens CO* adsorption at Pd sites and enhances OH* affinity at Cu sites, accelerating the oxidation and removal of CO* on Pd sites, boosting the methanol oxidation performance of PdCu alloys. The PdCu/C catalyst (Pd:Cu = 1:1) exhibited a remarkable mass activity of 1276.82 mA·mg_Pd^-1, 1.86 times higher than Pd/C (686.95 mA·mg_Pd^-1), and retained 61.3% of its activity in durability tests, surpassing Pd/C (48.4%). CO stripping tests further confirmed its superior CO tolerance. This work provides a pathway for developing high-performance, CO-tolerant anode catalysts suitable for advanced fuel cells.