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 nanoparticles deposited on carbon supported molybdenum trioxide (Pd–MoO 3 /C) is prepared with MoO 3 as the promoter for FAO. X-ray photoelectron spectroscopy analysis proves the close contact between Pd and MoO 3 , 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 CO ad and facilitate the durability and anti-CO poisoning ability of the catalyst. With the optimized ratio of MoO 3 to carbon black, the Pd–MoO 3 /C-20 catalyst owns the best specific activity of 5.86 mA cm −2 , which is 1.86 times of Pd/C.