Photocatalytic degradation of aromatic pollutants using plasmonic Cu–Ag nanocomposites

Commercially viable solutions are required for the environmental pollution challenges that are plaguing the global community. Development of cost-effective and visible light active photocatalysts for degrading persistent organic pollutants was attempted herein. Copper (Cu) and silver (Ag) nanoparticles and their nanocomposites at various ratios were explored for pollutant degradation in presence of visible light. Para-nitrophenol (p-NP) was used as a model pollutant to compare the catalytic activities of the nanomaterials. The silver rich nanocomposite (CuAg2) was found to be the most active photocatalyst because of its stronger ability to harvest light and synergistic charge transfer between Cu and Ag. CuAg2 could photocatalytically mineralize pharmaceutical compounds such as sulfamethoxazole (SMX) and norfloxacin (NOR) in presence of a small amount of H2O2. Photogenerated hydroxyl radicals were found to be responsible for the degradation of the pollutants. Moreover, the CuAg2 could be used as a surface enhanced Raman spectroscopy (SERS) substrate for detecting the pollutants. Operando catalytic activity studies also could be conducted using the CuAg2. Finally, liquid chromatography-mass spectrometry (LC-MS) was used to understand the possible degradation pathways for SMX and NOR.