Effect of MoO3 on Pd nanoparticles for efficient formic acid electrooxidation

Palladium is a promising formic acid electro-oxidation (FAO) catalyst due to its higher initial activity than platinum. However, suffering from the adsorption of hydrogen and CO-like species, the activity and stability of Pd are still unsatisfied. Herein, palladium nano-particles deposited on carbon supported molybdenum trioxide (Pd-MoO3/C) is prepared with MoO3 as the promoter for FAO. X-ray photoelectron spectroscopy analysis proves the close contact between Pd and MoO3, which generates the hydrogen spillover effect and forms the Pd-Mo structure. The hydrogen spillover effect enhances the desorption of hydrogen from Pd and facilitates the FAO activity. Both the spillover effect and Pd-Mo structure contribute to the removal of COad and facilitate the durability and anti-CO poisoning ability of the catalyst. With the optimized ratio of MoO3 to carbon black, the Pd-MoO3/C-20 catalyst owns the best specific activity of 5.86 mA cm-2, which is 1.86 times of Pd/C.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.