Hexagonal AgBr crystal plates for efficient photocatalysis through two methods of degradation: methyl orange oxidation and CrVI reduction

Abstract

Semiconductor-based photocatalysts have been proposed owing to their potential applications in contaminated water remediation, where a silver halide exhibits more attractive performance. Herein, a hexagonal AgBr crystal plate has been synthesized through a facile solvothermal technique, which demonstrated high efficiency for wastewater management through two degradation pathways in the oxidation of methyl orange (MO) and the photo-reduction of hexavalent chromium (Cr^VI). In order to concretely evaluate the photocatalytic performance, reaction rate constants (κ) of MO and Cr^VI were calculated to be 0.43 min⁻¹ (>400 nm), 0.73 min⁻¹ (AM 1.5) and 0.01 min⁻¹ (>400 nm), 0.05 min⁻¹ (AM 1.5), which were calculated to be 2.9 and 7.7 times that of the irregular AgBr, respectively. Furthermore, the corresponding mechanisms were also put forward to deeply understand each photocatalytic process.