Facile Hydrothermal Synthesis of Copper Chromite Nanoparticles for Efficient Photocatalytic Degradation of Acid Orange 7 Dye

In this paper, the hydrothermal method was utilized for the facile synthesis of copper chromite nanoparticles in the absence (abbreviated as CC1) and presence of citric acid (abbreviated as CC2) and tartaric acid (abbreviated as CC3) as templates. The synthesized nanoparticles were characterized using different tools such as XRD, FT-IR, UV–Vis, FE-SEM, HR-TEM, and BET. The average crystallite size of the CC1, CC2, and CC3 samples is 25.45, 20.26, and 12.75 nm, respectively. The FT-IR spectra show two bands in the range 613–616 cm⁻¹ and 511–514 cm⁻¹, which are characteristic of the spinel copper chromite crystalline structure. The optical energy gaps of the CC1, CC2, and CC3 samples are 1.25, 1.88, and 1.92 eV, respectively. The synthesized nanoparticles were used for the degradation of the acid orange 7 dye under visible light irradiations. The highest % degradation was obtained at pH 2.5 and irradiation time = 40 min. The % degradation of the acid orange 7 dye using CC1, CC2, and CC3 photocatalysts at pH 2.50 and time = 40 min is 87.38, 96.52, and 98.81, respectively. The degradation of the acid orange 7 dye was markedly reduced with the addition of isopropyl alcohol or disodium ethylenediaminetetraacetate, confirming that the hydroxyl radicals and holes routes play a fundamental role in the degradation process of the acid orange 7 dye. The degradation of the acid orange 7 dye is slightly affected by the addition of ascorbic acid, confirming a minor concentration of oxygen anion radicals.