Efficient Photocatalytic Nitrogen Fixation over Cuδ+‐Modified Defective ZnAl‐Layered Double Hydroxide Nanosheets

Abstract

AbstractThe photocatalytic reduction of nitrogen (N2) with water (H2O) as the reducing agent holds great promise as a sustainable future technology for the synthesis of ammonia (NH3). Herein, the effect of oxygen vacancies and electron‐rich Cuδ+ on the performance of zinc‐aluminium layered double hydroxide (ZnAl‐LDH) nanosheet photocatalysts for N2 reduction to NH3 under UV–vis excitation is systematically explored. Results show that a 0.5%‐ZnAl‐LDH nanosheet photocatalyst (containing 0.5 mol% Cu by metal basis) affords a remarkable NH3 production rate of 110 µmol g−1 h−1 and excellent stability in pure water. The X‐ray absorption spectroscopy, electron paramagnetic resonance, and density functional theory calculations reveal that Cu addition imparts oxygen vacancies and coordinatively unsaturated Cuδ+ (δ < 2) with electron‐rich property in the ZnAl‐LDH nanosheets, both of which readily contribute to efficient separation and transfer of photogenerated electrons and holes and promote N2 adsorption, thereby both activating N2 and facilitating its multielectrons reduction to NH3.