Surfactants-assisted morphological regulation of BiVO4 nanostructures for photocatalytic degradation of organic pollutants in wastewater

Abstract

In this paper, BiVO4 nanostructures with different morphologies were synthesized via hydrothermal method with the assistances of polyvinyl pyrrolidone (PVP), cetyltrimethyl ammonium bromide (CTAB), and sodium dodecyl benzene sulfonate (SDBS). The structures and the photocatalytic activities of BiVO4, PVP-assisted BiVO4 (BiVO4-PVP), CTAB-assisted BiVO4 (BiVO4-CTAB), and SDBS-assisted BiVO4 (BiVO4-SDBS) were characterized systematically by various techniques and organic pollution degradation experiment. The photocatalytic performance of these nanoparticles on the degradation of rhodamine B (RhB) was as follows: BiVO4-SDBS > BiVO4-CTAB > commercial photocatalyst P25 (under UV light irradiation) > BiVO4 > BiVO4-PVP > commercial photocatalyst P25 (under visible light irradiation). Irregular flake-stacked BiVO4-SDBS exhibited smaller crystallite size and larger specific surface area (3.9 m2/g) than irregular blocky BiVO4, rice-grained BiVO4-PVP, and polyhedral BiVO4-CTAB, leading to the shortened diffusion distance of electron-hole pairs and the enhanced separation efficiency of photogenerated electron-hole pairs. Due to the efficient electron-hole pairs separation and the enhanced visible light absorption, 2.0 g/L of BiVO4-SDBS showed the complete photocatalytic degradation rate of 100% on RhB (10 mg/L, 50 mL) in aqueous solution with pH 2 after irradiating under visible light for 40 min. The holes and superoxygen radical played vital roles in the photocatalytic degradation of RhB. Such investigation provides guidance for the rational design of visible light-active photocatalysts for the degradation of organic pollutants in wastewater.