Coating NiAl-LDH nanosheets on heptazine-based crystalline carbon nitride nanosheets for boosted CO2 photoreduction

Abstract

Heptazine-based crystalline carbon nitride (HCCN) is a promising candidate for photocatalytic CO₂ reduction because of its low toxicity and excellent chemical/electronic properties. However, pristine HCCN nanosheets show low catalytic activities due to their poor intrinsic conductivity and serious charge recombination. Herein, an efficient cocatalyst of NiAl-layered double hydroxide (LDH) nanosheets was coated on the HCCN surface via a facile electrostatic self-assembly method. The charge-transfer resistance can be modulated through the delicate design of the close contact that forms between LDH and HCCN nanosheets. Experimental characterizations reveal that the electrostatic potential (EP) is responsible for such remarkable charge kinetics, which makes it easier for them to participate in the following photoreactions. The composite of LDH/HCCN exhibits an enhanced photocatalytic CO₂ reduction rate of 42.2 μmol g⁻¹ h⁻¹ with respect to pristine HCCN and LDH counterparts. This work provides an avenue into efficient charge transfer at the composite interface, offering an essential potential for engineering cocatalysts in artificial photosynthesis.