Plastron-mediated direct H2O2 synthesis

Abstract

Abstract Gas-liquid-solid catalytic reactions are ubiquitous in the chemical industry and environmental chemistry. The efficacy of these reactions is constrained by the inherently low solubility of gases in liquids and poor mass transfer of reactants/products to/from the catalyst surface. We show that a gas layer trapped on a hydrophobic catalyst (plastron) substantially enriches local gas concentration, alleviating mass-transfer limitations and accelerating reaction rates. Using gold-palladium catalyst for direct hydrogen peroxide synthesis as a model, hydrogen/air plastrons on hydrophobic organosilica yield up to a 20-fold rate enhancement without sub-ambient temperatures, high pressures, or alcohol co-solvents. Combined with selective adsorption of butanethiol on gold-palladium nanoparticles, plastrons further inhibit undesirable decomposition pathways of hydrogen peroxide by repelling water from the catalytic center, eliminating the need for acid and halide promoters. This strategy serves as a new class of heterogeneous catalysts for gas-liquid-solid reactions, offering a route to chemical processes with reduced cost and carbon footprint.