Visible-light-driven overall water splitting with a largely-enhanced efficiency over a Cu2O@ZnCr-layered double hydroxide photocatalyst

Overall water splitting through solar radiation is highly attractive for alternative energy utilization. Herein, we designed and fabricated a Cu2O@ZnCr-layered double hydroxide (LDH) core-shell photocatalyst to achieve a high-performance, visible-light overall water splitting. The Cu2O@ZnCr-LDH nanostructure exhibits a high activity (with H2 and O2 production rate of 0.90 and 0.44 μmol h−1, respectively) under visible-light without any sacrificial agent and co-catalyst, which is among the highest level of reported photocatalysts under the same conditions. Both experimental and computational investigations demonstrate that the Cu2O@ZnCr-LDH heterostructure fully exploits the synergistic effect of Cu2O and ZnCr-LDH, in terms of band structure matching. Most significantly, the S2O32− group in the gallery of ZnCr-LDH acts as an effective mediator between these two individual components, which not only inhibits the photocorrosion of Cu2O but also accelerates the immigration of photo-induced electron-hole pairs. Therefore, this work provides a deep insight for the design and preparation of visible-light-responsive photocatalysts, which show promising applications in photochemical reactions and energy conversion.