Dominant Effect of Support Wettability on the Reaction Pathway for Catalytic Wet Air Oxidation over Pt and Ru Nanoparticle Catalysts

摘要

Support wettability can play a key role in directing the activation of oxygen during catalytic wet air oxidation over nanoparticle catalysts. When the nanoparticles are composed of metallic Pt, the optimum support is hydrophobic, but when they are ionic Ru, a hydrophilic support is more effective. This reversal in support effect is consistent with two distinct surface pathways: one in which gas-phase O_(2) is directly adsorbed on the Pt~(0) surface and the other in which dissolved O_(2) is activated on RuO_(2) immersed in the contaminated aqueous phase. The known effects of ceria on these precious metal catalysts are of secondary importance to support wettability.