Visible light activated MoS₂/ZnO composites for photocatalytic degradation of ciprofloxacin antibiotic and hydrogen production

In the photocatalysis process, photon energy is mainly converted into chemical energy with the help of both light and catalyst. This process can be used in different applications like photocatalytic degradation of hazardous compounds, fixation of nitrogen, hydrogen production, air purification, water splitting, carbon dioxide reduction etc. In this research work, multiplicative ZnO and MoS₂/ZnO (MZ) composites were synthesized using green chemical methods like the hydrothermal process and used in two different applications i) photocatalytic degradation of ciprofloxacin (CIP) antibiotic and ii) hydrogen production. CIP is not easily biodegradable and is mainly used in various antibacterial treatments. The photocatalytic activity was tested for ZnO and different MoS₂/ZnO composites along with this the effect of different amounts of catalysts doses was studied. MoS₂/ZnO composites exhibit superior photocatalytic performance than ZnO for photocatalytic degradation of CIP. Using the LC-MS technique possible degradation pathways are proposed. The same photocatalyst materials were used to test the photocatalytic H₂ production activity. H₂ production rates were found to be 22, 39 and 235 µmol/g/h for ZnO, MoS₂ and MZ-30 composite respectively. Superior photocatalytic activity of MZ-30 composite than ZnO is chiefly attributed to the extended light absorption capacity, effective charge transfer, suitable band alignment between the ZnO and MoS₂, minimum recombination of charge carriers etc.