Water pollution is a global issue as a consequence of rapid industrialization and urbanization. Organic compounds which are generated from various industries produce problematic pollutants in water. Recently, metal oxide (TiO 2 , SnO 2 , CeO 2 , ZrO 2 , WO 3 , and ZnO)-based semiconductors have been explored as excellent photocatalysts in order to degrade organic pollutants in wastewater. However, their photocatalytic performance is limited due to their high band gap (UV range) and recombination time of photogenerated electron–hole pairs. Strategies for improving the performance of these metal oxides in the fields of photocatalysis are discussed. To improve their photocatalytic activity, researchers have investigated the concept of doping, formation of nanocomposites and core–shell nanostructures of metal oxides. Rare-earth doped metal oxides have the advantage of interacting with functional groups quickly because of the 4f empty orbitals. More precisely, in this review, in-depth procedures for synthesizing rare earth doped metal oxides and nonocomposites, their efficiency towards organic pollutants degradation and sources have been discussed. The major goal of this review article is to propose high-performing, cost-effective combined tactics with prospective benefits for future industrial applications solutions.

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Thin films of GeTe, Ge2Sb2Te5 and Sb2Te3 have been synthesized from their respective polycrystalline bulk by thermal evaporation. X‐ray diffraction study of the films confirms the amorphous nature of GeTe and Ge2Sb2Te5 films, but as‐deposited Sb2Te3 film was in the crystalline form. Structural analysis has been performed for the annealed films above their crystallization temperature by XRD, which was evaluated by temperature‐dependent sheet resistance measurements. The Sb2Te3 film, which was already crystalline, undergoes a small transition at 110 °C. For optical studies, the transmittance and the reflectance spectra were measured over the wavelength ranges 400–2500 nm using UV‐VIS‐NIR spectroscopy. The optical bandgap, reflectance and optical contrast are also presented for thermally evaporated thin films. The dc electrical conductivity of the as‐deposited films has been measured as a function of temperature below the phase‐transition temperature, and increases exponentially with temperature. The value of the activation energy, calculated from the slope of lnσ versus 1000/T, is found to decrease from one end binary GeTe to pseudobinary Ge2Sb2Te5 and then to the other end binary Sb2Te3 films. On the basis of the pre‐exponential factor, the type of conduction in these films has also been discussed in the measured temperature range.

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