Cobalt Doping in NiAl-LDHs Boosts Visible-Light-Driven Photocatalytic CO ₂ Reduction

Doping engineering offers an effective route to tailoring light harvesting and charge-transfer properties for photocatalytic CO 2 reduction. Herein, multiflower-like layered double hydroxide Ni 1.5 Co 1.5 Al-LDH assembled from interconnected nanosheets was synthesized via a facile hydrothermal method. The incorporation of an optimal amount of Co 2+ and the induction of oxygen vacancies synergistically broaden the visible-light absorption range and accelerate the electron transfer rate. Under visible-light irradiation, Ni 1.5 Co 1.5 Al-LDH delivers a CO evolution rate of 761.19 μmol·g –1 ·h –1, which is 3.9 and 1.5 times higher than those of Ni 3 Al-LDH and Co 3 Al-LDH, respectively. Notably, Ni 1.5 Co 1.5 Al-LDH preserves the three-dimensional multiflower-like architecture of Ni 3 Al-LDH, providing accessible catalytic sites and shortening the charge-transport pathways. In addition, abundant vacancies promote the formation of Co 2+ -V O Lewis acid–base pairs, enhancing CO 2 adsorption and thereby contributing to the improved activity.