Photocatalytic performance of Li1−xAgxVMoO6 (0 ⩽ x ⩽ 1) compounds

• The synthesis of Li1−xAgxVMoO6 (0 ⩽ x ⩽ 1) compounds with lamellar structure.
• The evaluation of mixed metal oxides Li1−xAgxVMoO6 (0 ⩽ x ⩽ 1) as photocatalysts.
• A comparison of Li1−xAgxVMoO6 (0 ⩽ x ⩽ 1) and TiO2 Degussa P25.
• Ag does not improve Li1−xAgxVMoO6 (0 ⩽ x ⩽ 1) photocatalytic performance.
• Li1−xAgxVMoO6 (0 ⩽ x ⩽ 1) photocatalytic performance is superior to TiO2.

In this work we report the influence of silver content on the structure and photocatalytic performance of Li1−xAgxVMoO6 compounds for the oxidation of benzyl alcohol under UV irradiation (λ = 254 nm). Photocatalysts were synthesized by solid state method and their structural and morphologic characterization was carried out by powder X-ray Diffraction, Raman Spectroscopy, SEM, TEM, UV–Vis diffuse reflectance spectroscopy and XPS. The effect of variables including silver content, temperature, catalyst concentration and initial concentration of benzyl alcohol on photocatalytic performance were studied. Experimentation was also carried out with TiO2 (Degussa P25) as reference. It was found that all tested Li1−xAgxVMoO6 (0 ⩽ x ⩽ 1) compounds exhibit higher photocatalytic efficiency than TiO2. However, among mixed oxides, silver was found to diminish their catalytic performance and selectivity towards benzaldehyde. The latter was affected in much less extent than activity (94%, 90% and 87% for LiVMoO6, Li0.8Ag0.2VMoO6 and AgVMoO6, respectively). Kinetic modelling was carried out based on Langmuir–Hinshelwood type expressions. Apparent activation energies were found to be 42 kJ mol−1 and 60.17 kJ mol−1 for LiVMoO6 and TiO2, respectively.

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