Enhanced photocatalytic degradation of Diclofenac with Agl/CeO2: A comparison with Mn, Cu and Ag-doped CeO2.

• Sol-gel synthesis produce more active CeO 2 photocatalyst over combustion synthesis. • Metal doping, Ag, Cu, Mn, of CeO 2 increases bandgap but decreases photocatalytic activity. • Efficient photocatalytic degradation of diclofenac with AgI-doped CeO 2. • 2.6-fold increase in quantum efficiency of AgI/CeO 2 over CeO 2 obtained. Diclofenac, an emerging pollutant, has long half-life and can lead to antibiotic resistance, destruction of aquatic ecosystem, etc. We studied the photocatalytic destruction of diclofenac using ceria synthesized through combustion synthesis and sol gel methods. The combustion synthesis method gives a catalyst with a higher surface area, though with a lower photoactivity. Sol gel ceria was then doped with metal ions: Mn, Cu, Ag to give metal-semiconductor and with AgI to give n-p semiconductor-semiconductor heterojunction photocatalysts. Mn/CeO 2 , Cu/CeO 2 and Ag/CeO 2 showed lower photoactivity, while AgI/CeO 2 showed better activity over the native CeO 2. Over 97% removal of diclofenac was obtained in less than 120 min using 125 W UV light. A 2.6-fold increase in the quantum efficiency was obtained on doping CeO 2 with AgI. The enhanced activity of AgI-doped CeO 2 is attributed to improved charge separation of electron-hole pairs generated on irradiation with UV light. [Display omitted] [ABSTRACT FROM AUTHOR]