Component-dependent activity of bimetallic PdCu and PdNi electrocatalysts for methanol oxidation reaction in alkaline media

In the work, the catalytic performance and reaction mechanism of methanol oxidation reaction(MOR) are studied for the bimetallic PdxCuy and PdxNiy catalysts in alkaline solution. The results reveal that the Pd1Ni1/C and Pd1Cu1/C bimetallic catalysts exhibit high catalytic activity 4.1 and 3.9 times higher than that of the commercial Pd/C catalyst. Combined with the X-ray diffraction (XRD), High-resolution transmission electron microscopy(HRTEM) and X-ray photoelectron spectroscopy (XPS) analysis, the charge transfer between Pd and Cu(or Ni) alters the electron density of Pd and enhances the anti-CO poisoning ability, which is confirmed by DFT (Density Functional Theory) calculations. The CO binding energy is weakened on various bimetallic surfaces compared with that on Pd(111), consistent with experimental results. A linear relationship exists between the CO binding energy and the catalytic activity on the bimetallic catalysts, indicating that the CO binding energy may be the potential descriptor for MOR in alkaline media. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.