Synthesis of Visible Light Active Delafossite Structured CuCrO2: Optical and Photocatalytic Studies

Abstract

Synthesis of delafossite structured CuCrO2 by sol-gel method using tartaric acid as a complexing agent is reported in present study. The product has been characterized by powder X-ray diffraction, thermal analysis (TGA/DTA), SEM, Raman spectra, BET (surface area analysis) and UV-Vis-diffused reflectance spectroscopy. Powder X-ray diffraction revealed the formation of delafossite structured CuCrO2 phase at 800 ºC for 3 h, which was further confirmed by thermal analysis that showed one weight loss and endothermic peak at above 800 ºC corresponded to the phase transition. Hexagonal plate like morphology of the synthesized powder was confirmed by SEM analysis. The Raman spectra showed three Raman scattering peaks of the delafossite structure of CuCrO2. Diffused reflectance spectroscopy (DRS) revealed that the band gap of the prepared CuCrO2 microcrystals was about 2.90 eV. In addition, the synthesized CuCrO2 was used for the degradation of p-nitrophenol and H2 generation under visible-light which showed 32.4 μmol (10.8 μmol/h) of H2 and 92 % degradation of p-nitrophenol (20 mg/L) after 4 h of visible light irradiation. Further analysis revealed that •OH and •O2 − were the main ROS responsible for p-nitrophenol degradation.