Solvothermal Synthesis of Bismuth-Based Halide Perovskite Nanostructures for Photocatalytic Degradation of Organic Pollutants under LED Light Irradiation
Vinh Huu Nguyen, Taeyoon Lee, Trinh Duy Nguyen
Abstract
The use of bismuth-based halide perovskites for photocatalysis has attracted increasing attention because of their matching photoelectric properties and the nontoxicity of bismuth metal. However, organic–inorganic halide perovskites with chloride as halides possess a large band gap, restricting their potential use in visible-light-activated photocatalytic processes. In this study, a bismuth-based halide perovskite nanostructure, tris(tetramethylammonium) nonachlorodibismuthate (((CH 3 ) 4 N) 3 Bi 2 Cl 9 ), has been successfully synthesized through a solvothermal process using a mixture of dichloromethane/ N, N -dimethylformamide as both solvent and reagent. The results show that, when dichloromethane and N, N -dimethylformamide are combined simultaneously during synthesis, Bi-based halide perovskite nanostructures are formed with a reduced midgap-state-induced energy gap. The formation of ((CH 3 ) 4 N) 3 Bi 2 Cl 9 was confirmed through X-ray diffraction patterns and Fourier transform-infrared spectroscopy. The presence of localized states extended in the band gap (referred to as midgap states) was demonstrated by ultraviolet–visible diffuse reflectance and photoluminescence spectroscopy. The ((CH 3 ) 4 N) 3 Bi 2 Cl 9 samples exhibit super photocatalytic activity for Rhodamine B and tetracycline hydrochloride degradation in an aqueous solution under visible-light irradiation. The bismuth halide perovskite (BHP-30-30 sample) exhibited a Rhodamine B degradation efficiency of 99.4% in 30 min and a tetracycline hydrochloride degradation efficiency of 78.4% in 3 h. The fact that this catalyst is recyclable four times further demonstrates the promise of BHP-30-30 as a replacement visible-light-sensitive catalyst for removing organic pollutants.