Calcined ZnTi-Layered Double Hydroxide Intercalated with H3PW12O40 with Efficiently Photocatalytic and Adsorption Performances

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=[PW12O40](3-)) was synthesized by calcining the ZnTi-layered double hydroxide (ZnTi-LDH) intercalated with the Keggin-type polyoxometalate H3PW12O40. 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.