Efficient Photocatalytic Nitrogen Fixation over Cu<i><sup>δ</sup></i><sup>+</sup>‐Modified Defective ZnAl‐Layered Double Hydroxide Nanosheets
Shuai Zhang, Yunxuan Zhao, Run Shi, Chao Zhou, Geoffrey I. N. Waterhouse, Li‐Zhu Wu, Chen‐Ho Tung, Tierui Zhang
Abstract
Abstract The photocatalytic reduction of nitrogen (N 2 ) with water (H 2 O) as the reducing agent holds great promise as a sustainable future technology for the synthesis of ammonia (NH 3 ). Herein, the effect of oxygen vacancies and electron‐rich Cu δ + on the performance of zinc‐aluminium layered double hydroxide (ZnAl‐LDH) nanosheet photocatalysts for N 2 reduction to NH 3 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 NH 3 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 Cu δ + (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 N 2 adsorption, thereby both activating N 2 and facilitating its multielectrons reduction to NH 3 .