Surfactants Modulating of BiVO4 on Photocatalytic Property as a Regulation of Surface Free Energy

BiVO4 is a stable photocatalytic material but has poor photocatalytic activity in visible light. Herein, the surfactants were investigated to enhance the photocatalytic degradation of tetracycline (TC) of BiVO4 through a hydrothermal method. The different molecular structures and properties of surfactant-modified BiVO4 show clustered small spheres and stacked plate-like microcrystals. The N-hexadecyltrimethylammonium chloride (CTAC)-modified BiVO4 (BiVO4-CTAC) with stacked plate-like morphology increases the light absorption range and decreases the energy band gap. Surfactants with different hydrophilic groups and molecular structures affect the formation process of BiVO4, regulating the morphology, crystal structure, and crystalline surface exposure of BiVO4. BiVO4-CTAC has demonstrated superior TC degradation efficiency compared with the original BiVO4 (BiVO4-Blank). This enhancement is attributed to the observation in the Nyquist plot, where BiVO4-CTAC exhibits the smallest arc radius, indicative of reduced charge transfer resistance and improved charge separation. Furthermore, holes (h+) and superoxide radicals (•O2–) reactive species are the main active radicals for TC photocatalytic degradation. This study develops a novel method to synthesize monoclinic phase lamellar BiVO4 materials by simply changing the surfactant type. This study holds potential implications for advancing surfactant-assisted synthesis of high-efficiency photocatalysts.