Flower-like CoAl layered double hydroxides modified with CeO2 and RGO as efficient photocatalyst towards CO2 reduction

In this article, a simple yet effective in situ hydrothermal method has been developed to synthesize a series of CeO2 and reduced graphene oxide (RGO) stepwise-doped CoAl-LDH (CACR) composites with CoAl-LDH/ CeO2 (CAC) as the intermediate. The smart design well integrates the photo-electrochemical merits of CoAlLDHs and CeO2 with conductive RGO to form an optimized formula with high light-harvesting ability, efficient charge separation, and rapid electron transfer. Owing to these features, the sample of CAC-5-R-10 containing 5 wt% CeO2 and 10 wt% RGO, is found to be the most efficient one as the catalyst for CO2 photoreduction with a high average CO evolution rate of 5.5 mu mol center dot g(-1)center dot h(-1) at 25 degrees C without sacrifice reagent or extra photosensitizer under ultraviolet light, which surpasses those of the single CeO2, CoAl-LDHs, the intermediate of CAC, and many reported LDH-based counterparts. With the assistance of Mott-Schottky curves, the Z-scheme mechanism is proposed for the significantly enhanced photo-activity of the CAC-5-R10. The present work provides a good sample for integrating LDHs with a second semiconductor and conductive RGO for collaborative optimization of photoelectric characteristics towards enhanced CO2 photoreduction. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

A series of CeO2 and RGO stepwise-doped CoAl-LDH composites were synthesized using a simple yet effective in situ hydrothermal method, with the sample of CAC-5-R-10 demonstrating the highest CO2 photoreduction catalytic efficiency.