Pb–Pd alloy catalysts with intercalated Pb atoms: optimized electronic and lattice structures for enhanced electrochemical ethanol oxidation

Abstract

A facile one-step method is employed to synthesize carbon-supported Pd–Pb binary metal catalysts for the ethanol oxidation reaction (EOR) in alkaline electrolytes. A variety of characterization techniques have demonstrated that the alloying of Pd with Pb alters the electronic structure and induces lattice expansion. Electrochemical tests for the EOR in alkaline electrolytes demonstrated that the Pd₃Pb/C catalyst exhibited the highest mass activity (3.59 A mg_Pd⁻¹) and specific activity (17.97 mA cm⁻²), which are 4.6 and 4.7 times those of the Pd/C catalyst prepared by the same method, respectively. The intercalation of lead atoms has altered both the lattice and the electronic structure of palladium, leading to opposing shifts in the d-band center that collectively optimize the adsorption strength of CO* and OH*, key intermediates of the EOR. Consequently, the Pd₃Pb/C electrocatalyst exhibits significant EOR catalytic activity. This study provides a viable implementation plan and analytical strategy for optimizing palladium-based catalysts with non-noble metals by integrating electronic transfer, bifunctional effects, and d-band center adjustments for bimetallic catalysts.