Photocatalysis is essential for wastewater cleanup and clean energy, and in this current study, we have synthesized nanomaterials (iron oxide-based) for photocatalytic pollution degradation and hydrogen production. The performance of aluminium oxide/ferric oxide (Al₂O₃/Fe₂O₃), samarium oxide/ferric oxide (Sm₂O₃/Fe₂O₃) and yttrium oxide/ferric oxide (Y₂O₃/Fe₂O₃) were compared for the production of hydrogen (H₂) and degradation of dye under natural sunlight. Various characterisation equipment was used to characterize these photocatalysts’ structure, morphology, elemental content, binding energy and band gap. The hydrogen recovery efficiency of iron oxide-based photocatalysts from sulphide-containing wastewater is assessed. Y₂O₃/Fe₂O₃ has shown the highest hydrogen production of 340 mL/h. The influence of operating factors such as sulphide ion concentration, catalyst quantity, and photocatalyst photolytic solution volume on hydrogen production is studied. The optimal values were 0.25 M, 0.2 g/L, and 1L, respectively. The developed photocatalyst passed multiple cycles of stability testing. Fe₂O₃ has shown the highest Rhodamine B (RhB) dye degradation efficiency of 94% under visible light.

The present study investigated the microstructural properties of ordinary Portland cement (OPC)-modified with minimum dosage of nano TiO₂ on fresh and hardened cement mortar surfaces and intermixed samples. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) were used to analyze the morphology and hydration products of the OPC specimens doped with nanotitanium (NT).Additionally, XRD coupled with Rietveld refinement was employed to quantify the crystal phases and refine the crystal structure model through the comparison of the calculated diffraction pattern to the measured pattern. Subsequently, crystallographic analysis was conducted to evaluate the crystallographic structure and to confirm the existence of specific atoms and bonds within the crystal structure altered with NT. The findings revealed that the addition of minimal NT resulted in a more compact and denser microstructure, characterized by increased formation of calcium silicate hydrate (CSH) gel and a reduction in calcium hydroxide (CH) crystals.This led to a reduction in the porosity of the hardened coating surface, with similar improvements observed for the fresh coating and intermixed samples compared to those of the control mortar. A decrease in the lattice parameters, accompanied by an increase in the number of atoms, bonds and polyhedra in the crystal structure, led to alterations in the interatomic spacing and contributed to the densification of the cementitious matrix.The findings also showed that NT integration led to a more compact structure with shorter bond distances and smaller polyhedral volumes for the Ti samples than for the control sample. Moreover, compared with the freshly cast and hardened coating samples, the NT-intermixed samples exhibited the shortest Ti–O bond distances and the smallest polyhedral volume. Overall, the analysis presented in this study significantly contributes to the development of novel and environmentally friendly photocatalytic cementitious materials at minimal dosages.

The present study investigated the structural, microstructural, and crystallographic changes associated with the addition of nano-TiO₂ (NT) by intermixing and surface coating on freshly cast and hardened coatings on white Portland cement matrix samples at minimal dosages. Scanning electron microscopy (SEM) and VESTA were employed to analyze the microstructure morphology of the hydration products and the crystal structure parameters of the NT-modified white Portland cement mortar. Additionally, Rietveld refinement analysis was performed to quantify the crystal phases coupled with XRD using Xpert High Score Plus and Expo-2014 software. The Rietveld refinement analysis of the hardened coating surface followed by the fresh cast coating resulted in the most refined structural model compared with that of the intermixed and reference samples. The integration of NT also reduced the bond distances and polyhedral volumes, indicating denser atomic packing and enhanced interactions between the smaller NT particles and the white Portland cement matrix and enhancing the structural integrity within the matrix. Furthermore, SEM micrographs revealed a compact microstructure with enhanced CSH and reduced CH crystals in the NT-modified white cement mortar samples. The presence of hydration products and corresponding bonds were confirmed by Fourier Transform Infrared Spectroscopy.