Features of the electronic structure and photocatalytic properties under visible light irradiation for RbTe1.5W0.5O6 with β-pyrochlore structure

The compound RbTe1.5W0.5O6 with beta-pyrochlore structure has been recently obtained as visible-light photocatalysts material, which is capable for dye decomposition. The refinement of electron structure has been performed based on transmittance and diffuse reflectance spectra. The ability for visible light absorbance is related to impurity defect absorbance band (similar to 2.5 eV) in the electron structure, despite the wide band gap (similar to 3.4 eV). The active radical species, led to methylene blue photooxidation, have been predicted using electronic structure and confirmed experimentally using radical's scavengers. The significant impact of electron-hole pair's recombination process on photocatalytic efficiency has been found out for powder with average size particle of 700 nm, and it has been improved by decreasing the particles size up to 300 nm. The apparent quantum efficiency has been calculated and compared for prepared samples with different particles size. Moreover, the oxidized products of methylene blue have been defined and the possible oxidation pathway has been proposed.