Efficient Adsorption-Assisted Photocatalysis Degradation of Congo Red through Loading ZIF-8 on KI-Doped TiO₂

Zeolitic imidazolate framework-8 (ZIF-8) was evenly loaded on the surface of TiO₂ doped with KI, using a solvent synthesis method, in order to produce a ZIF-8@TiO₂ (KI) adsorption photocatalyst with good adsorption and photocatalytic properties. The samples were characterized by XRD, SEM, EDX, XPS, BET and UV-Vis. The photocatalytic efficiency of the material was obtained by photocatalytic tests. The results indicate that the doping with I inhibited the grain growth and reduced the crystallite size of TiO₂, reduced the band gap width and improved the utilization rate for light. TiO₂ (KI) was a single crystal of anatase titanium dioxide. The combination of ZIF-8 and TiO₂ (KI) improved the specific surface area and increased the reaction site. The ZIF-8@TiO₂ (KI) for Congo red was investigated to validate its photocatalytic performance. The optimal concentration of Congo red solution was 30 mg/L, and the amount of catalyst was proportional to the degradation efficiency. The degradation efficiency of ZIF-8@TiO₂ (5%KI) was 76.42%, after being recycled four times.