Controllable Modification of the Electronic Structure of Carbon-Supported Core–Shell Cu@Pd Catalysts for Formic Acid Oxidation

Abstract

This study analyzes the synthesis of carbon-supported core–shell structured Cu@Pd catalysts (Cu@Pd/C) through a galvanic replacement reaction to be utilized in the electrocatalytic oxidation of formic acid. The strategy used in this study explores the relationship among lattice strain, electronic structure, and catalytic performance. X-ray diffraction and X-ray photoelectron spectroscopy indicate that the inclusion of Cu in the nanocatalyst increases lattice strain and results in a downshift of the d-band of palladium. Electrochemical tests show that Cu@Pd/C catalysts exhibit weaker adsorption strength for CO with increased Cu content, which can be attributed to the downshift of the electronic d-band. For the synthesized materials, the Cu@Pd/C catalyst with a Cu:Pd atomic ratio of 27:73 is found to have the highest activity for formic acid oxidation. A peaklike plot between activity and atomic composition is acquired and reveals the relationship among lattice strain, electronic structure, and catalytic performance.