Rapid and efficient visible-light-actuated green photocatalytic synthesis of aniline from toxic nitrobenzene through novel mesoporous AgVO3/Bi2WO6 nanosheets

Abstract

Heterogeneous photocatalysis, a "green" approach, could convert numerous noxious materials (such as nitrobenzene) into valuable compounds (such as aniline). Unfortunately, the inadequate efficiency of photoinduced charge carriers' segregation, ineffectual light harvesting efficiency, and the poor stability of the photocatalyst in the solution are significant challenges for photocatalytic applications. In this report, for the first time, two-dimensional (2D) mesoporous AgVO3/Bi2WO6 heterojunctions were fabricated through a facile surfactant assisted-hydrothermal route, followed by impregnation and calcination, using different AgVO3 contents (4–16 wt%), to be applied for phototransformation of nitrobenzene into aniline under visible illumination. Physicochemical characterization revealed that the nanosheet configuration and porous nature of Bi2WO6 did not alter after loading AgVO3. However, the AgVO3 loading greatly affected the Bi2WO6 catalyst's textural, absorption, and energy bandgap. Notably, only 12 wt% AgVO3 on the Bi2WO6 surface led to dropping the specific surface area from 140 to 125 m2 g−1, improving the absorption edge from 452.06 to 536.05 nm, and reducing the band gap from 2.74 to 2.23 eV. Just 2.4 g L−1 of the optimum AgVO3/Bi2WO6 photocatalyst (12 wt% AgVO3) displayed a complete photoreduction for nitrobenzene to aniline within only 40 min with outstanding reusability and recyclability. The AgVO3 significantly improved photoinduced charge carriers' separation and migration through a step (S)-scheme heterojunction with Bi2WO6. This study opens the door to developing the green conversion of wastes into value-added compounds through heterogeneous photocatalysis.