Asymmetric Electron Redistribution in Niobic-Oxygen Vacancy Associates to Tune Noncovalent Interaction in CO 2 Photoreduction.

The role of vacancy associates in photocatalytic CO 2 reduction is an open question. Herein, the Nb─O vacancy associates (V Nb─O ) are engineered into niobic acid (NA) atomic layers to tailor the CO 2 photoreduction performance. The intrinsic charge compensation from O to Nb around Nb─O vacancy associates can manipulate the active electronic states, leading to the asymmetric electron redistribution. These local symmetry breaking sites show a charge density gradient, forming a localized polarization field to polarize nonpolar CO 2 molecules and tune the noncovalent interaction of reaction intermediates. This unique configuration contributes to the 9.3 times increased activity for photocatalytic CO 2 reduction. Meantime, this V Nb─O NA also shows excellent photocatalytic activity for NO 3 - -NH 4 + synthesis, with NH 4 + formation rate up to 3442 µmol g -1 h -1 . This work supplies fresh insights into the vacancy associate design for electron redistribution and noncovalent interaction tuning in photocatalysis.