Titanium dioxide (TiO2)-decorated silver indium diselenide (AgInSe2): novel nano-photocatalyst for oxidative dye degradation

Abstract

Novel visible-NIR photocatalysts prepared via the hybridization of wide and small bandgap semiconductors involving silver indium diselenide (AgInSe₂) and titanium dioxide by thermal and microwave methods are presented. The process revealed the formation of new hybrid nanostructured materials with remarkably different properties than the parent semiconductors. New catalysts were characterized by various advanced analytical tools such as UV-visible diffuse reflectance, Raman spectroscopy, XRD, SEM, EDS, TEM, XPS, and BET. Changes in the optical properties in comparison to the parent compounds, namely, AgInSe₂ and TiO₂, resulted in a broad absorption band covering the entire UV-visible region, which confirmed successful coupling. The XRD pattern revealed the presence of diffraction peaks from both the parent semiconductors. TEM showed spherical morphology with the presence of small TiO₂ NPs on the surface of AgInSe₂ NPs. In situ-formed silver selenide can also generate useful AgInSe₂ in the hybridized form, which showed rather excellent photocatalytic performance. The so-prepared hybrid nanostructured materials were tested for photocatalytic activity against three organic dyes, namely, methylene blue (MB), methyl orange (MO), and rhodamine B (RhB). The photocatalytic degradation efficiency was 89% for AgInSe₂/Ag₂Se against MB, which was better than the parent semiconductors. AgInSe₂/TiO₂ showed almost no loss in the degradation efficiency even after reuse for five times, confirming its stability and effectiveness.