Constructing subtle grain boundaries on Au sheets for enhanced CO 2 photoreduction

Photocatalytic reduction of CO 2 into value-added products is a promising strategy for mitigating environmental and energy problems simultaneously. Herein, we developed Au sheets with subtle grain boundaries on ultrathin Ni(OH) 2 nanosheets as efficient photocatalysts for CO 2 reduction. According to mechanistic studies, grain boundaries on the Au sheets served as electron trapping sites which enabled the optimization of electron-hole separation. Moreover, grain boundaries perturbed electron distribution, which assisted in stabilizing CO 2 δ − and HCOO* intermediates. As a result, the unique hybrid structure achieved a high rate of 75.2 µmol g −1 h −1 for CO 2 photoreduction. This work demonstrates the importance of defect engineering in designing active photocatalysts and also provides insight into development of related photo-energy conversion schemes.