Sunlight-driven photocatalytic degradation of Rhodamine B by BiOCl and TiO2 deposited on NiCr-LDH

Abstract

ABSTRACT NiCr-LDH/BiOCl and NiCr-LDH/TiO2 nanocomposites were successfully synthesised by co-precipitation and hydrothermal methods. Their structure, morphology and optical properties were analysed by XRD, SEM, UV−vis, XPS and FTIR techniques. The Rhodamine B (RhB) dye was used as a model pollutant to evaluate the catalytic activity for the nanocomposites under sunlight irradiation for 60 min. The results showed a significant enhancement in the photocatalytic activity of NiCr-LDH/BiOCl (up to 96.57%), higher than that of NiCr-LDH/TiO2 (89.58%), and pure phase NiCr-LDH (26.09%). The nanocomposites exhibited a high catalytic performance than TiO2 and BiOCl pure phases. This funding was not related to the Bi or Ti content but to the dispersion of the pure phase on the surface of the NiCr-LDH. The enhanced photocatalytic activity of the NiCr-LDH/BiOCl naocomposite mainly attributed to the formation of heterojunction between LDH and BiOCl for efficient separation of photoinduced electrons and holes. Hydroxyl radicals and holes were the main active species. Both NiCr-LDH/BiOCl and NiCr-LDH/TiO2 photocatalysts exhibited high stability and reusability even after four cycles. Based on the experimental results, a possible photocatalytic mechanism on both nanocomposites was proposed.