Efficient photocatalytic nitrogen fixation over novel 2D/2D Bi12O17Br2/ZnCr layered double hydroxide heterojunction

Herein, a novel ultrathin 2D/2D heterostructure, Bi 12 O 17 Br 2 with oxygen vacancies/ZnCr layered double hydroxides (V o -Bi 12 O 17 Br 2 /ZnCr-LDHs, V o -BZ) is prepared by solvothermal and coprecipitation methods for photocatalytic reduction of N 2 to NH 3 . The optimal 2D/2D V o -BZ heterostructure photocatalyst shows production rate of ammonia production of 286.0 μmol·g −1 ·h −1 . It is 12.5 and 3.6 times higher than that of pure ZnCr-LDHs and V o -Bi 12 O 17 Br 2 . The improved photocatalytic nitrogen reduction performance is attributed to the intimate contact interface, matching bandgap structure, the shortened migration distance, and thus significantly improved separation and transfer efficiency of hole-electron pairs and light adsorption ability. The large number of oxygen vacancies and high specific surface promote the absorption, activation and deionization of N 2 molecules. The theoretical simulation calculation indicates that the free energy of nitrogen molecules on the surface of Vo-BZ is favorable for the absorption and activation of N 2 molecules. The existence of oxygen vacancies and formation of heterojunctions can dramatically reduce energy barrier of nitrogen molecule hydrogenation process to boost photocatalytic N 2 reduction. This study provides a new idea for the development of efficient photocatalytic nitrogen fixing catalysts.