Constructing active lattice oxygen in high covalent perovskites for boosting catalytic activity

Abstract

Transition-metal (TM) active centers are solely considered to probe the intrinsic origin of catalytic activity, but the interaction between metal and oxygen has been overlooked. Herein, an effective approach is demonstrated to adjust the degree of TM–O covalency, enhancing the intrinsic catalytic activity via Cu substitution and acid etching. spectroscopic investigations and theoretical calculations reveal that improved catalytic performances are attributed to enhanced TM–O covalency. Owing to the strong hybridization between TM 3d and O 2p orbitals, the intramolecular electrons are transported from oxygen to TM cations, promoting asymmetric electron redistribution and inducing oxygen holes (electrophilic O) generation. Ligand oxygen holes as preactive oxygen centers achieved the initial activation of reactant molecules and lattice oxygen activation, ultimately boosting the heterogeneous catalytic activity. The findings highlight a new method to design highly covalent perovskite oxides with sufficient ligand oxygen holes to trigger lattice oxygen activation in the catalytic fields.