Dual-Function Surface Hydrogen Bonds Enable Robust O2 Activation for Deep Photocatalytic Toluene Oxidation

Abstract

Solar-driven molecular oxygen activation by semiconductor photocatalysts is a prototypical reaction manifesting complex interactions among photons, charge carriers, and reactants. In this study, we demonstrate energetic O2 activation towards volatile organic compounds control can be realized via constructing a sophisticated surface hydrogen bond (HB) network bearing a dual-function. The extensive HBs established between hydroxyl-rich BiOCl surface and phosphoric acid are first shown to significantly weaken surface Bi-O bonds, enabling facile oxygen vacancies (OVs) generation. OVs, which act as the reliable electron capture and static O2 activation center, reinforce the interaction between photons and excitons for rapid charge carriers separation. Moreover, dynamic O2 activation with sluggish kinetics can be surmounted by another type of HBs localized between hydroxyl groups of phosphoric acid and OV-adsorbed O2. These unique localized HBs facilitate interfacial electron transfer from BiOCl to O2, displaying a unique energy coupling route between charge carriers and reactants. For simulated indoor toluene oxidation, the substantially boosted O2 activation is shown to accelerate the kinetic processes associated with the primary oxidation of toluene into benzaldehyde and benzoic acid, as well as aromatic ring opening towards deep oxidation. Undesirable intermediates accumulation and catalyst deactivation are thus avoided. The present work highlights the pivotal roles of HB for robust photocatalytic O2 activation. It will provide novel insights into the design of high-performance catalysts for efficient and safe control of indoor volatile organic compounds.