Calcined ZnTi-Layered Double Hydroxide Intercalated with H₃ PW₁₂ O₄₀ with Efficiently Photocatalytic and Adsorption...

Wastewater treatment is of great significance to environmental remediation. The exploration of efficient and stable methods for wastewater treatment is still a challenging issue. Herein, a heterojunction material with photocatalysis and adsorption properties has been designed to remove the complex pollutants from wastewater. The heterojunction material (ZnO/TiO₂ -PW₁₂ , PW₁₂ =[PW₁₂ O₄₀ ]^3- ) was synthesized by calcining the ZnTi-layered double hydroxide (ZnTi-LDH) intercalated with the Keggin-type polyoxometalate H₃ PW₁₂ O₄₀ . In the construction of ZnO/TiO₂ -PW₁₂ it was found that the polyanionic PW₁₂ remained unchanged in the process of forming the proposed heterojunction. The photochemical properties verify that heterojunction synergistic with PW₁₂ facilitated the separation of photoproduced electron-hole pairs and thus suppressed the recombination. Therefore, ZnO/TiO₂ -PW₁₂ exhibits excellent photocatalytic property, and the efficiency of Cr(VI) photoreduction reached more than 90 % in the first 3 min. Furthermore, the electrostatic force between the PW₁₂ and cationic dyes makes ZnO/TiO₂ -PW₁₂ having an outstanding adsorption performance for cationic dyes, such as rhodamine B, crystal violet and methyl blue. Such heterojunction material combined with polyoxometalate puts forward new insights for the design of functional materials for water treatment with low cost and high efficiency.