Hampered PdO Redox Dynamics by Water Suppresses Lean Methane Oxidation over Realistic Palladium Catalysts

By use of operando spectroscopies under cycling reaction conditions, water is shown to hamper the redox dynamics realistic palladium oxide nanoparticles dispersed onto alumina and hydrophobic zeolite supports thereby lowering activity for total oxidation methane. Water adsorption forms hydroxyl ad-species that block methane oxygen dissociation seem prevent lattice take part in oxidation. The main catalytic action thus proposed shift from Mars-van Krevelen mechanism dry conditions a slower route relies on Langmuir-Hinshelwood type steps wet conditions. This key finding has clear implications catalyst design low-temperature gas combustion emission control.