A low temperature hydrothermal method is employed in this study to synthesize CdSe doped TiO₂ nanocomposites. Further characterization and studies of the synthesized particles were carried out. As part of this study, the sample was examined by X-ray diffraction to determine its structure, crystallite size, strain, and crystallinity. Molecules were analyzed by energy dispersive X-ray spectroscopy to determine their chemical composition. By using fourier transform infrared spectroscopy spectroscopy, we were able to observe the presence of functional groups as well as the types of bonds. By analyzing the scanning electron microscopy spectra, we were able to determine the particle size while by analyzing the photoluminescence spectra, we could determine the bandgap energy. To determine the nature of materials and their effective photocatalytic behavior, optical bandgap energies were observed in the ultra-violet visible spectrum of synthesized particles. For determining the charge transfer mechanism and specific capacitance, electrochemical studies were conducted using electrochemical impedance spectroscopy and cyclic voltammetry analysis. The degradation of malachite green and Rhodamine-B dyes with CdSe doped TiO₂ nanocomposites in the visible region was studied for photocatalytic activity, degradation efficiency, and rate constant. According to the results, doped nanoparticles increased the efficiency of RhB dye degradation by ~ 4% and MG dye degradation by ~ 20% over pure nanoparticles.

The titanium dioxide (TiO₂) nanoparticles were prepared by hydrothermal methods at ambient temperature. Based on XRD analysis, the average crystallite size of pure TiO₂ nanoparticles and those doped with ZnS was calculated to be 58 and 54 nm, respectively. At an angle of 25.4°, the prominent peak observed at the (101) plane of TiO₂ was confirmed. As can be seen from the collection of peaks, the TiO₂ formed has an anatase‐type tetragonal crystal structure. A strain of −6.4541 × 10⁻⁴ and a grain size of 33 nm can be seen in the W–H plot for TiO₂ nanoparticles. For doped ZnS nanoparticles, on the other hand, the values are 1.9448 × 10⁻⁴ and 47 nm. In our study, we found that doped nanoparticles were average grain size 134 nm, while pure nanoparticles were average grain size 146 nm. Doping reduces the size of the nanomaterial, which means that the TiO₂ molecules form nanoclusters on their surfaces, which can lead to a larger grain size for a pure nanoparticle than for a doped nanoparticle. A wide range of functional groups and their associated bonds were investigated using FTIR spectra in synthesized nanomaterials. TiOTi bonds are subjected to a strong stretching vibration, which is confirmed by the absorption peaks from 450 cm⁻¹ to 800 cm⁻¹. The PL spectra for pure TiO₂‐ and ZnS‐doped TiO₂ containing nanocomposites of ZnS emit ultraviolet light at wavelengths of 362 and 379 nm in the UV region. Pure and doped samples with optical bandgap energies of ~3.04 and ~3.8 eV corresponding to anatase phases were near ~3.18 eV in Tauc plots. Since the TiO₂‐doped ZnS heterojunction migrates photoexcited holes toward the interface, while electrons migrate toward the bulk, this results in photoexcited holes migrating toward the interface. To calculate the specific capacitance of the synthesized materials, cyclic voltammetry with pure ZnS and those with ZnS‐doped had specific capacitance values of 144.91 F/g and 120.11 F/g, respectively. The catalysts used were ZnS nanocomposite doped with TiO₂ in addition to pure TiO₂ nanoparticles. The degradation of dye within 80 min after sunlight exposure was monitored with a UV–Vis spectrophotometer at 20‐min intervals. ZnS nanoparticles doped with TiO₂ display 87.8% greater efficiency than pure nanoparticles. Doped TiO₂ nanocomposite degrades at an 87.8% rate, whereas pure TiO₂ degrades at ~54%, indicating that the dopants enhance photocatalysis.

To remove toxic wastes from water bodies by using a photocatalyst is the objective of this paper. Chemically, pure TiO ₂ and TiO ₂ ‐doped Bi ₂ O ₃ nanoparticles are synthesized using the low temperature hydrothermal method. The properties of the synthesized nanoparticles were studied using various characterization methods. In addition to powder X‐ray diffraction (PXRD) and scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDAX), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and Fourier transform infrared (FTIR) analyses, we studied the structural and surface morphology of the nanoparticles. By analyzing those data, we can determine the average crystallite size, strain, crystallinity, the molecular composition, the grain size of the nanoparticles, the structure, shape, functional groups, and types of bonds between them. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) analyses were used for electrochemical studies. Based on these data, a study was conducted on charge transfer and specific capacitance. Photoluminescence (PL) and ultra‐visible absorbance (UV–vis) spectra were used to determine the optical properties. Based on these spectra, it is possible to determine the optical bandgap of the particles and their potential as photocatalysts. Under a visible light radiation source, pure TiO ₂ and TiO ₂ ‐doped Bi ₂ O ₃ nanocomposites were used in the photocatalytic degradation of malachite green (MG) and Rhodamine‐B (RhB) dyes. By studying the observations, we were able to determine the degradation efficiency, as well as the rate constant. Results showed that the TiO ₂ ‐doped Bi ₂ O ₃ nanocomposites showed an increase in degradation efficiency of ~0.8% for RhB dye and ~27.7% for MG dye when compared to pure TiO ₂ nanoparticles.

The SnO₂-TiO₂ binary nanocomposites’ metal oxide was synthesized by a co-precipitation method and potentially utilized for wastewater treatment applications. The average crystallite size, dislocation density, and micro strain of the synthesized nanocomposites were calculated by the Debye–Scherrer, modified Debye–Scherrer, and W–H methods. The nanocomposites exhibit a tetragonal crystal structure with 62% crystallinity. The presence of Ti–O–Ti and Sn–O–Sn bonds was identified using the FTIR technique. The surface morphology was examined during SEM and EDAX analyses. The optical properties were interpreted with the help of UV–Vis and PL spectroscopy, and the bandgap energy was ascertained. From the CV and EIS studies, the behavior of the diffusive and capacitive natures was determined. Photocatalytic studies were carried out under sunlight and UV light by degrading (cationic) malachite dye at concentrations of 10, 20, and 40 mg/L. When analyzed with seven kinetic models, it was inferred that a pseudo-second and first-order were followed under visible and UV light. The maximum degradation efficiency of 94% was achieved for the 20 mg/L dye concentration within 50 min under UV and 150 min under solar irradiation. Complete decolorization was observed for both 10 mg/L and 20 mg/L dye concentrations under both irradiations.