CoAl-LDH@CoSx loaded BiVO4-NBC composites: constructing a novel in-built electric field to enhance photocatalytic performance for persistent pollutants in water

Abstract This paper presents a biomass char based photocatalyst CoAl-LDH@CoSx-BiVO 4 -NBC composite, which was prepared by hydrothermal method using corn stover biomass as biomass char precursor through three modifications both: urea calcination modified biocarbons, sodium sulphide etching of CoAl-LDH combination, and composite BiVO 4 . The results showed that the composites degraded p-aminobenzoic acid in 93.4% under xenon lamp irradiation. The improved photocatalytic performance of the CoAl-LDH@CoSx-BiVO 4 -NBC composites was attributed to the effective reduction of the agglomeration of the LDH by the N-BC biomass char base in the composites, which at the same time provided a larger specific surface area. Different characterisation methods: X-ray diffractometer, scanning electron microscope, Fourier infrared spectrometer, solid-state UV spectrophotometer, fluorescence spectrophotometry, etc., were also applied to investigate the influence of the physical and chemical properties on the photocatalytic performance. In addition, the effects of catalyst dosage, pH and degradant concentration in the photocatalytic system on the experimental system were investigated. Finally, liquid chromatography-mass spectrometry (LC-MS) analysis and density functional theory (DFT) were used to analyse the possible degradation pathways in the photocatalytic system. This paper provides a novel pathway for recycling waste biomass for persistent pollutant treatment and preparation of new photocatalysts.