Palladium on Carbon-Catalyzed Gentle and Quantitative Combustion of Hydrogen at Room Temperature

A quantitative and gentle oxidation (combustion) of hydrogen in the presence of oxygen in a variety of solvents was achieved under palladium on carbon (Pd/C)‐catalyzed conditions at ordinary pressures and temperatures. A quantitative generation of water accountable for the consumed oxygen was observed. While hydrogen peroxide (H2O2), which would form as an intermediate, was extremely unstable under the Pd/C‐catalyzed conditions to be converted into water with accompanying oxygen generation, the stability of H2O2 was found to be increased in cold (0 °C) trifluoroacetic acid, and the formation of 64% H2O2 based on the consumed oxygen could be detected. A mechanistic elucidation study revealed that the single electron transfer and generation of the hydroxyl radical are involved in the gentle combustion process. The reactive oxygen species generated during the process was effectively utilized for the chemical oxidation of sulfides and phosphines to afford the corresponding sulfoxides and phosphine oxides, respectively.