Silver-doped zinc oxide nanoparticles: synthesis, characterization and optimization of photocatalytic efficiencies in...

Solar photo-oxidation represents an environmentally friendly approach using solar radiation as the primary energy source. Among semiconductor photocatalysts, zinc oxide (ZnO) nanoparticles have been extensively investigated due to their favorable photocatalytic performance. However, their practical application in solar-driven processes remains limited by their low photocatalytic efficiency under ultraviolet (UV) irradiation, which accounts for only approximately 5% of the solar spectrum. This limitation is mainly attributed to the rapid recombination of photogenerated electron-hole pairs (e^-/h⁺). To overcome this drawback, the present study focuses on silver-doped zinc oxide (Ag/ZnO) photocatalytic materials. Owing to their high electrical conductivity, silver nanoparticles act as electron traps, thereby enhancing charge separation and reducing electron-hole recombination. ZnO and Ag/ZnO nanocomposites were successfully synthesized using a soft co-precipitation method. The structural properties of the synthesized materials were thoroughly characterized. Their functional properties, including optical behavior and photocatalytic performance, were subsequently investigated to determine the optimal operating conditions. The photocatalytic performance was evaluated under both UV and visible irradiation using photocatalytic efficiency (ρ). Different silver doping levels (0, 0.25, 0.50, 0.75, and 1 wt%) were evaluated. The results demonstrated a clear dependence of photocatalytic efficiency on the silver content. The Ag/ZnO composite containing 1 wt% Ag exhibited the highest performance, with a photocatalytic efficiency of 0.67 × 10^-3 as compared with 0.4 × 10^-3 for ZnO. These findings confirmed that silver doping effectively enhanced the photocatalytic properties of ZnO and improved its potential for solar-driven environmental applications.