Photochemical Ammonia Synthesis over Reduced Polyoxovanadate-Intercalated Defective ZnAl Layered Double Hydroxide Nanosheets

A series of reduced polyoxovanadateswere intercalated intocopper-induced ZnAl layered double hydroxide nanosheets with oxygenvacancies via an anion exchange strategy toward green ammonia production. Theexploration of efficient and stable N-2 fixationphotocatalysts featuring a broad absorption spectrum and N-2 fixation active sites has become specifically conspicuous. Herein,a series of reduced polyoxovanadates (POVs) were intercalated intocopper-induced ZnAl layered double hydroxide (0.5%-ZnAl LDH) nanosheetswith oxygen vacancies via an anion exchange strategy toward greenammonia production. The intervalence charge transfer arising frommixed-valence POV materials is responsible for its light-harvestingbehavior, and the LDHs lay the foundation for the chemical adsorptionand activation process of nitrogen molecules; both contributions facilitatethe nitrogen photofixation performance of such composite materials.As predicted, the catalytic efficiency of V-34/0.5%-ZnAlis 7.0 times higher than 0.5%-ZnAl LDH. Therefore, such an all-inorganicsystem exhibits an apparent quantum efficiency of 0.3137% at 500 nm.The strategy of working in tandem established by POV-basedlight-absorber species and oxygen vacancies as the sites for N-2 activation is extremely vital for enhanced ammonia formation.This work opens up a versatile insight for the rational design ofan efficient photo-driven nitrogen-reduction composite catalyst towardsustainable ammonia production compared to the industrial Haber-Boschprocess.

Automated summary

A series of reduced polyoxovanadates were intercalated into copper-induced ZnAl layered double hydroxide nanosheets with oxygen vacancies through an anion exchange strategy for green ammonia production. This work is of great significance for the rational design of an efficient photo-driven nitrogen-reduction composite catalyst for sustainable ammonia production.