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.