Mechano-thermally synthesized CuCrO2/CuCr2O4 nanocomposite and improvement of photocatalytic activity by structure modification

In this paper, CuCrO2/CuCr2O4 nanocomposite powder was synthesized by a solid-state mechano-thermal reaction between Cu2O and Cr2O3 powder, and the effect of 20 h initial ball milling on various properties was studied. The improvement of photocatalytic activity through the modification of the structure was also studied. The results showed that ball milling before the heat treatment process has led to the formation of a nanocomposite of spinel CuCr2O4 and delafossite CuCrO2. According to the field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) results, after 20 h of ball milling, the microstructure became fine and homogeneous, and the powder with an average particle size of 174 ± 5 nm was observed. The X-Ray Photoelectron Spectroscopy (XPS) study shows the formation of CuCrO2/CuCr2O4 through the mechano-thermal process. The ball milling process narrowed the bandgap of the photocatalyst to 2.60 eV. The lower intensities of the nanocomposite photoluminescence (PL) peak indicated a lower electron-hole pair recombination rate. Also, the nanocomposite produces a current density of 1.77 times higher than the single-phase CuCrO2 sample. In methylene blue (MB) degradation, a favorable photocatalytic performance (85%) under visible light irradiation was obtained with the nanocomposite photocatalyst. the degradation of MB over both photocatalysts was approximately 50% higher than that of methyl orange (MO). After 3 runs of the photocatalytic test on the nanocomposite sample, no significant loss in the performance of the photocatalyst was observed.