In Situ Growth of Perovskite on 2D Hydrothermal Carbonation Carbon for Photocatalytic Reduction of Nitrate to Ammonia
Leyan Wei, Yuying Zhang, Chunyan Zhang, Chao Yao, Chaoying Ni, Xiazhang Li
Abstract
Photocatalytic ammonia synthesis from waste nitrate provides a green strategy for water treatment, which holds great significance for the global water cycle. However, there is still a lack of highly efficient catalysts to meet the high conversion and selectivity. Herein, a nanostructured photocatalyst was prepared by assembling perovskite (LaFeO 3 ) on hydrothermal carbonation carbon (HTCC) via a facile microwave hydrothermal method, which was employed to reduce nitrate to ammonia. The two-dimensional HTCC nanosheet had a large specific surface area and abundant surface functional groups, and Fe/La salt participated in the surface modification of HTCC, promoting the exposure of oxygen-containing functional groups and aromatic structure, which was favorable for the nitrate adsorption. Furthermore, the HTCC constructed a p–n heterojunction with LaFeO 3, which improved the photocatalytic activity attributed to the fast separation of photogenerated electron holes. At the optimized mass ratios of pomegranate peel to Fe/La salt, the LaFeO 3 /HTCC photocatalyst achieved a highest nitrate removal of 94.6% and an ammonia selectivity of 88.7% under visible light irradiation. This work provides the approach for the photocatalytic synthesis of ammonia from residual nitrate pollutants.