Enhanced photocatalytic activity and stability of WO3-AgCl/Ag composites: Surface modulation by structure-directing agents for effective sunlight treatment of pharmaceutical wastewater

In this work, different structure-directing agents (citric acid, oxalic acid, urea, polyethylene glycol and Triton X100) were used to synthesize WO3-AgCl photocatalysts by a simple one-step hydrothermal method. The successful synthesis of the materials was proved through various characterization techniques (XRD, BET, SEM, TEM, EDS, UV-vis DRS, XPS, EPR, Mott-Schottky and photoluminescence). The directing agent strongly influenced the morphology of the catalysts, with the material synthesized with citric acid showing the most homogeneous distribution of WO3 and AgCl particles, and the highest photocatalytic activity (100.0% acetaminophen removal after 30 min; k = 0.212 min -1). Stability tests resulted in a performance reduction of only 18.8% after four cycle times. Degradation in real effluent from a pharmaceutical industrial facility showed 83.6% acetaminophen removal. In addition, experiments in a continuous microstructured packed bed reactor revealed 97.9% steadystate contaminant removal.