COF-5/CoAl-LDH Nanocomposite Heterojunction for Enhanced Visible-Light-Driven CO2 Reduction

Graphical Photocatalytic CO 2 reduction : A COF-5/CoAl-layered double hydroxide (LDH) heterojunction photocatalyst is developed for the CO 2 reduction reaction. CoAl-LDH incorporation enhances the visible-light response-ability of the photocatalyst and improves the separation efficiency of photogenerated electron–hole pairs through the role of a type-II heterojunction. Photocatalytic conversion of CO 2 into value-added chemical fuels is an attractive route to mitigate global warming and the energy crisis. Reasonable design of optical properties and electronic behavior of the photocatalyst are essential to improve their catalytic activity. Herein, the 1D/2D heterojunction by direct in-situ synthesis of the covalent organic framework (COF)-5 colloid on the surface of CoAl layered double hydroxide (LDH) was used as the prospective photocatalyst for CO 2 reduction. COF-5/CoAl-LDH nanocomposite achieved 265.4 μmol g −1 of CO with 94.6 % selectivity over CH 4 evolution in 5 h under visible light irradiation, which was 4.8 and 2.3 times higher than those of COF-5 colloid and CoAl-LDH, respectively. The enhanced catalytic activity was derived from the increased visible-light activity and the construction of type II-2 heterojunction, which greatly optimized visible light harvesting and accelerated the efficient separation of the photoinduced holes and electrons. This work paves the way for rational design of heterojunction catalysts in photocatalytic CO 2 reduction.