Preparation and characterization of Mo6V8.5Te0.5O40 mixed oxide with intrinsic redox couples as an efficient photocatalyst for dye degradation

Molybdenum and vanadium mixed oxides of Mo6V9O40 and Mo6V8.5Te0.5O40 were synthesized by the modified sol-gel method. The phase formation and structure were investigated through X-ray powder diffraction (XRD) patterns. The optical absorption measurements show that the sample has an efficient light response covering the region UV-visible to near IR wavelength. The two Mo-V mixed oxides of Mo6V9O40 and Mo6V8.5Te0.5O40 show an indirect forbidden transition with band energies of 1.67 eV and 1.64 eV, respectively. The multivalent cations (V and Mo ions) were confirmed via X-ray photoelectron spectroscopy (XPS) measurements. The effective photocatalysis of the samples was conducted via the photodegradation of RhB under visible-light irradiation (lambda >= 420 nm). The conductivity properties and lifetime of charge carriers were characterized via impedance spectra and luminescence decay curves respectively. It was suggested that intrinsic redox couples in these Mo-V mixed oxides lead to intervalence transfer between V5+/(4+) and Mo6+/(5+) couples, which can improve photocatalysis. This work offers a potential alternative material with rich intrinsic redox couples and defects toward high-performance photocatalyst. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Molybdenum and vanadium mixed oxides were synthesized and their phase formation, optical absorption, and photocatalytic properties were investigated. The results showed that these mixed oxides exhibited efficient light response and improved photocatalysis due to the presence of intrinsic redox couples. This study provides a potential alternative material for high-performance photocatalysts.