Dynamic restructuring of Pd–Pt concave nanocubes boosts methanol oxidation

Methanol oxidation reaction (MOR) is a key process in direct methanol fuel cells (DMFCs), determining both energy efficiency and stability. Despite efforts, the impact of dynamic structural changes of Pt-based catalysts on MOR performance remains poorly understood. Here, we report on the impact mechanism of dynamic changes on MOR performance in the Pd–Pt concave nanocubes (CNCs) system. Pt with high-index facets exposed abundant active sites for methanol oxidation, resulting in an exceptional mass activity of 0.89 A·mg_Pt⁻¹. Pd underwent an oxidation-redeposition process during MOR, dynamically restructuring the catalyst and producing a volcano-type activity. Pd^δ+ species generated during oxidative etching promoted OH* formation, accelerating CO oxidation on Pt sites, thus mitigating poisoning. With continued cycling, redeposited Pd partially blocked Pt sites, counteracting the positive effect of the generated Pd^δ+. The dynamic balance of Pd oxidation and redeposition governed the activity evolution while sustaining the exceptional durability of Pd–Pt CNCs during prolonged cycling.