Introducing of a novel polyoxometalate-based organic–inorganic hybrid: Insights into electochemical property-photoactivity relationship

Abstract

Herein a new visible photocatalyst by TiO2 and nanosized polyoxometalate-based inorganic–organic hybrid material, NaH8[PDA]3[PW9Co3O37]·13H2O (PDA = p-phenylenediamine) (PDA-Co3W9), were successfully synthesized by an new straight forward method. Prepared powder was characterized by, FT-IR, PL, XRD, UV–Vis, DRS, and FE-SEM techniques. The FE-SEM images of the nanocomposite showed spherical-like nanoparticles with the mean size particle of 20–30 nm. The resulting materials were evaluated in the photodegradation of dye, using different light illuminations. Under optimized conditions, 100% dye removal was obtained. Tauc plots showed different bandgaps for different PDA-Co3W9 weight percentages on TiO2 (PDA-Co3W9/TiO2). The amplified photodegradation properties would be owing to the synergetic effect of PDA, Co3W9 and TiO2 as components. Optimization of conditions were studied by response surface methodology. Also, relationship between effective factors and electrochemical properties of photocatalyst was investigated by Mott-Schotcky, Nyqist, and Bode plots. Vfb, ND, and lifetimes of photogenerated electron–hole separation were calculated and compared with each other according to the photoactivity of different kinds of the catalysts. Specific capacitance of the best photocatalyst was calculated. Mechanism of photodegradation and reusability of the catalyst were also investigated.