Photocatalytic oxidation of formaldehyde under visible light using BiVO₄-TiO₂ synthesized via ultrasonic blending

Formaldehyde (HCHO) is one of the primary indoor air pollutants, and efficiently eliminating it, especially at low concentrations, remains challenging. In this study, BiVO₄-TiO₂ catalyst was developed using ultrasonic blending technology for the photocatalytic oxidation of low-level indoor HCHO. The crystal structure, surface morphology, element distribution, and active oxidation species of the catalyst were examined using XRD, SEM, TEM, UV–Vis, EDS, and ESR techniques. Our results demonstrated that the BiVO₄-TiO₂ catalyst, prepared by ultrasonic blending, exhibited good oxidation performance and stability. The HCHO concentration reduced from 1.050 to 0.030 mg/m³ within 48 h, achieving a removal rate of 97.1%. The synergy between BiVO₄ and TiO₂ enhanced the efficiency of separating photogenerated carriers and minimized the likelihood of recombination between photogenerated electrons and holes. Additionally, this synergy significantly enhanced the presence of hydroxyl radicals (·OH) on the catalyst, resulting in an oxidation performance superior to that of either BiVO₄ or TiO₂. Our research offers valuable insights for the development of new photocatalysts to address HCHO pollution.