Effect of Chelating Agents on the Structural, Optical, and Dye-Degradation Properties of Tungsten Oxide Nanoparticles

Abstract

A simple co-precipitation method was used to create pure tungsten oxide (WO3) nanoparticles using phthalic acid, citric acid, and oxalic acid as chelating agents. The influences of chelating agents on the structural, morphological, and optical properties were investigated. X-ray diffraction (XRD) patterns of WO3 nanoparticles showed the existence of combined phase of anorthic-monoclinic for all the samples, and the crystalline size was found to be reduced while using oxalic acid. The vibrational band observed in the region around (500–800 cm−1) in the FTIR spectra indicates the formation of WO3 nanoparticles. SEM images revealed the formation of WO3 agglomerates. The energy-dispersive X-ray (EDX) spectra of the WO3 nanoparticles confirmed the purity of synthesized nanoparticles. The enhanced light-absorption ability of oxalic-acid-assisted WO3 nanoparticles are inferred from the decreased band gap energy in UV–vis absorption spectra. The PL spectra showed emission in both the UV and visible regions. The optimized reaction parameters for obtaining high catalytic efficiency are identified by varying the concentrations of oxidant, catalyst, and dye during the catalytic reaction. The synthesized WO3 nanoparticles exhibited better catalytic degradation of CV than MB and RB dyes even with the lesser quantity of catalyst material.