Penta-coordinated aluminum species: Anchoring Au single atoms for photocatalytic CO2 reduction

Searching substrate materials having inherent photocatalytic activity and interaction with single atoms remains challenge. Herein, amorphous Al₂O₃ containing penta-coordinated aluminum (Al^V) species is synthesized using the solvothermal method and the Au single atom is anchored by Al^V via the self-reduction strategy. The Al-O bond energy is weakened by introducing amorphous components, which benefits the release of oxygen atoms and the resultant change of Al coordination environment to a Al^V species. The electron transfer between Al^V and Au stabilizes the Au single atom. The introduction of the Au single atom occupying the position of O vacancy and anchored by Al^V strengthened the chemical absorption abilities for CO_2, lowered the energy barrier of CO generation and promoted the charge separation efficiency. The CO generation rate of the Au single atom anchored obtains extraordinary promotion in comparison with pristine Al₂O₃, resulting in an approximately 6-fold enhancement and 98% product CO selectivity.