Dynamic structural reconstruction of CuO under reaction conditions enhances photocatalytic activity in CH bond functionalization

The dynamic structural reconstruction of semiconductor photocatalysts caused by the generated corrosive by-products seriously affects their catalytic activity. Contrary to the conventional perception of acid corrosion as a detrimental factor in photocatalytic reactions, we demonstrate that in-situ acidic etching during photocatalytic arene C H trifluoromethylation reaction can generate oxygen vacancies, lattice dislocations, twinning boundaries and localized amorphous domains in cupric oxide (CuO) photocatalyst, leading to remarkable activity enhancement. The in-situ characterization and kinetic studies reveal that the generated acidic byproducts (trifluoromethylsulfonic acid and SO 2 ) induce a self-optimizing reconstruction of CuO via continuous Cu 2+ leaching. These structural changes enhance charge separation and induce electron redistribution in CuO, optimizing the interaction between active sites and reaction intermediates, thereby accelerating the reaction kinetics in trifluoromethylation reactions as well as photocatalytic oxidation of olefins and toluene. This work sheds light on the understanding of dynamic reconstruction in affecting photocatalytic efficiencies of semiconductor photocatalysts and redefines the role of acid corrosion in semiconductor photocatalyst design.