Cyclodextrin-mediated synthesis of PdM (M=Co, Ni) bimetallic ultrafine nanocatalyst for efficient oxygen reduction reaction

Abstract

Developing active and stable Pd-based materials is crucial to design cost-effective, efficient, and highly durable catalysts for oxygen reduction reaction (ORR). Herein, PdM/NC series ultrafine nanoparticles alloy catalysts (2.50 nm PdCo/NC, 2.75 nm PdNi/NC) with enhanced atomic utilization were synthesized via cyclodextrin-assisted pyrolysis. Moreover, the DFT (density functional theory) calculation and experiment demonstrated that Co, Ni doping and nitrogen incorporation optimize Pd's electronic structure, improving ORR performance. PdCo/NC and PdNi/NC exhibits superior activity (half-wave potential:0.858 V, 0.820 V; Tafel slope: 58.23 mV dec⁻¹, 56.63 mV dec⁻¹) and stability (88.58 % and 89.52 % current retention after 12 h continuous operation). Practical zinc-air batteries using PdCo/NC and PdNi/NC cathodes demonstrate high open-circuit potentials (1.49 V and 1.46 V) and peak power densities (125.77 mW cm⁻² and 96.77 mW cm⁻²). This work provides strategic insights for designing ultrafine nanoparticle catalysts, advancing zinc-air battery development through optimized energy efficiency and durability in oxygen electrocatalysis.