Hybridization-Driven Introduction of Anion Vacancies to Boost the Photocatalytic Nitrogen Fixation Functionality of Low-Lattice-Energy Nanosheets

Defect engineering has attracted considerable research interest owing to its effectiveness in optimizing the catalytic performance of inorganic solids. Herein, we develop a hybridization-assisted defect control approach to fabricate efficient visible-light-active photocatalysts comprising low-lattice-energy nanosheets via a synergetic combination of hybridization and defect engineering. The hybridization between Cu–Cr-layered double hydroxide (Cu–Cr-LDH) and g-C 3 N 4 nanosheets having relatively low lattice energies effectively increases the defect concentration and improves photocatalyst performance for the visible-light-driven N 2 reduction reaction (NRR). Using defect-introduced holey g-C 3 N 4 nanosheets as building blocks further reinforces the interfacial interaction with the hybridized Cu–Cr-LDH nanosheets, producing additional crystal defects. The defective g-C 3 N 4 –Cu–Cr-LDH nanohybrid exhibits exceptional NRR activity showing an outstanding NH 4 + formation rate of 1.45 mmol h –1 g cat –1 and one of the best NRR catalytic performances among the recently reported LDH-based photocatalysts. Combined in situ spectroscopic analysis and theoretical calculation reveal that the reinforced coupling with vacancy-introduced g-C 3 N 4 nanosheets effectively improves the photocatalytic activity and stability of Cu–Cr-LDH via the facilitation of the associative reaction pathway. The high efficacy of hybridization-assisted defect control for efficient generation of photocatalysts is attributable to the mutual enhancement of defect concentration and interfacial interaction, which improves N 2 adsorption/activation, light absorption, and charge transport properties and prevents the recombination of electron–hole pairs.