Core-shell Bi-containing spheres and TiO2 nanoparticles co-loaded on kaolinite as an efficient photocatalyst for methyl orange degradation

Improving the efficiency/cost ratio is the key to the practical application of photocatalysts. Using cheap minerals as carriers is an effective means to improve the efficiency/cost ratio of photocatalysts. Here, kaolinite was used to co-load TiO2 nanoparticles and Bi containing core-shell spheres forming the composites with excellent photocatalytic performance. The rate constant per unit mass of TiO2 in the optimal sample reached 18 times that of TiO2. Kaolinite plays important roles in promoting photocatalytic activity by improving the dispersion of TiO2 and the adsorption of O2 molecules and MO anions, besides the type-II energy band alignment of TiO2 and BixOy. [Display omitted] •Photo active TiO2 and core(Bi)-shell(BixOy) have been co-loaded on kaolinite (KTB).•KTB is more efficient for the photocatalytic MO degradation than its components.•The rate constant per unit mass of TiO2 in 1.2KTB was 18 times that of pure TiO2.•TiO2 and bismuth oxide shell form a type-II heterojunction.•Kaolinite improves the dispersion of TiO2 and favors the adsorption of O2 and MO.