Oxalic acid coordination-induced Pd/carbon dot nanowires with tunable Pd-N electronic coupling toward oxygen reduction reaction

The large-scale deployment of alkaline fuel cells is still hindered by the sluggish cathodic oxygen reduction reaction (ORR) and the high cost of Pt-based catalysts. Herein, interconnected Pd/carbon-dot (Pd/CD) nanowires were fabricated through an oxalic-acid-assisted coordination strategy coupled with temperature-controlled reduction for efficient alkaline ORR. Nitrogen-doped carbon dots provide abundant anchoring sites for Pd species, while oxalic acid provides a mild reducing environment and coordinates with Pd 2+ through carboxylate groups. This process regulates Pd nucleation and growth, suppresses aggregation, and promotes interfacial electronic coupling. The catalyst prepared at 40 °C exhibits a well-dispersed, interconnected nanowire architecture with abundant accessible active sites. It delivers an onset potential of 0.996 V and a half-wave potential of 0.878 V, outperforming commercial Pt/C under identical testing conditions. X-ray absorption fine structure analysis and density functional theory calculations suggest that strong Pd–CD interfacial coupling optimizes the adsorption energetics of key oxygenated intermediates and reduces the ORR energy barrier. This work provides a coordination-regulated strategy for designing efficient Pd-based electrocatalysts for alkaline fuel-cell applications.