g‑C₃N₄/NiAl-LDH 2D/2D Hybrid Heterojunction for High-Performance Photocatalytic Reduction of CO₂ into Renewable Fuels

2D/2D interface heterostructures of g-C ₃N ₄ and NiAl-LDH are synthesized utilizing strong electrostatic interactions between positively charged 2D NiAl-LDH sheets and negatively charged 2D g-C ₃N ₄ nanosheets. This new 2D/2D interface heterojunction showed remarkable performance for photocatalytic CO ₂ reduction to produce renewable fuels such as CO and H ₂ under visible-light irradiation, far superior to that of either single phase g-C ₃N ₄ or NiAl-LDH nanosheets. The enhancement of photocatalytic activity could be attributed mainly to the excellent interfacial contact at the heterojunction of g-C ₃N ₄/NiAl-LDH, which subsequently results in suppressed recombination, and improved transfer and separation of photogenerated charge carriers. In addition, the optimal g-C ₃N ₄/NiAl-LDH nanocomposite possessed high photostability after successive experimental runs with no obvious change in the production of CO from CO ₂ reduction. Our findings regarding the design, fabrication and photophysical properties of 2D/2D heterostructure systems may find use in other photocatalytic applications including H ₂ production and water purification.