Highly photocatalytic activity for p-nitrophenol degradation with spinel-structured CuCr2O4

Nano-scale copper-chromium oxide (CuCr₂O₄) samples were synthesised by calcining their precursors prepared via a co-precipitation procedure. The as-prepared samples were characterised by thermogravimetry and differential thermal analysis, X-ray diffraction and scanning electron microscopy technologies, respectively. The results revealed that the size of the as-synthesised sample increased by increasing the calcination temperature. The resultant samples quenched at between 400 and 500°C were composed of nanoparticles, but the ones quenched at over 550°C showed octahedral morphology in shape. The final samples were used as photocatalyst for degradation of p-nitrophenol in wastewater with assistance of H₂O₂ under irradiation of visible light. The photocatalytic degradation properties, including irradiation time, catalyst concentration, pH, initial concentration of the pollutant and repeatability of the catalyst were investigated, respectively. The results indicated that CuCr₂O₄ samples could degrade effectively p-nitrophenol. After being used ten times, the catalyst still exhibited high catalytic activity. The technology possesses potential application in treatment to wastewater containing nitrophenol pollutant.