Ultrathin NiAl-Layered Double Hydroxides Grown on 2D Ti3C2Tx MXene to Construct Core–Shell Heterostructures for Enhanced Photocatalytic CO2 Reduction

Photocatalytic CO 2 reduction into renewable fuels by sustainable and clean solar energy can be considered as an ideal option to decrease the atmospheric CO 2 level and fulfill the energy requirements. Layered double hydroxides (LDHs) with high surface area, tunable composition as well as exposed active sites have received enormous attention for photocatalytic CO 2 reduction. Herein, a novel NiAl-LDH/Ti 3 C 2 T x nanosheet (NiAl-LDH/TNS) with a core–shell structure was synthesized via an in situ hydrothermal method, and 2D NiAl-LDH coupled with the 2D Ti 3 C 2 T x nanosheet to form a Schottky junction can suppress the back-diffusion of electrons and facilitate the transfer of charge carriers. Benefiting from the feature, the optimized sample with the additive Ti 3 C 2 T x amount of 75 mg (NiAl-LDH/TNS-75) has the photocatalytic CO 2 reduction conversion rate of CO (2128.46 μmol h –1 g –1 ) with the selectivity of CO (90.2%) under visible-light irradiation, which is about 8.6 times higher than that of pristine NiAl-LDH. This work provides a new insight into the construction of novel 2D semiconductor photocatalysts.