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 β-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 (∼2.5 eV) in the electron structure, despite the wide band gap (∼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. [Display omitted] •The refinement of the band gap structure of β-pyrochlore RbTe1.5W0.5O6 has been carried out.•The radical species generated on the RbTe1.5W0.5O6 surface under visible-light irradiation have been determined.•The possible pathway of methylene blue photocatalytic decomposition has been proposed.•The significant impact of recombination process on photocatalytic efficiency has been found out for 700 nm powder.•The powder sample with particles size at twice lower (300 nm) has almost absence of the recombination.