The present work scrutinizes a few uses of barium titanate BaTi1–xZrxO3 (0.0 ≤ x ≤ 0.3) nanoparticles, which are an innovative and highly promising material for a variety of applications, including optical applications; and waste water treatment. To estimate the quality of a synthesized powder relative to an already existing commercial powder, the samples were prepared using cheaper raw materials and simpler, faster procedures than those reported in other literature at lower annealing durations and temperatures. The prepared samples were characterized by field emission scanning electron microscopy (FESEM), and Raman spectroscopy, which confirmed the coarse nature of the samples and the system's tetragonality. Furthermore, UV–visible absorbance of all compositions was studied. It has been determined that optical transition is directly allowed after extensive research, and the optical band gap (Eg) values increase with increasing (Zr4+) ion concentration. The derivation of absorption spectrum fitting (DASF) technique was used to support the type of transition and calculate the value of the coefficient of electronic transition (n). Samples can perform overall water splitting and CO2 reduction processes. The Langmuir and Freundlich isotherms were used to comprehend the procedure of adsorption on the investigated samples. The BaTi0.8Zr0.2O3 has been used to successfully remove 99.9% of heavy metals (Cr6+) from wastewater. The obtained results provide new insights into the control of the structure, and optical behaviors in BaTi1–xZrxO3.
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