Effect of temperature and time on the hydrothermal synthesis of WO3-AgCl photocatalysts regarding photocatalytic activity

Abstract

Heterogeneous photocatalysis is an important and promising alternative for efficient water and wastewater treatment processes. The synthesis of composite materials has attracted attention due to their improved photocatalytic activity and stability. In the present work, composites made of WO3-AgCl were synthesized by a simple one-step hydrothermal method. The evaluation of the effects of reaction temperature and synthesis time for this composite is reported for the first time. The materials were characterized by XRD, SEM, TEM, EDS, BET, UV–vis DRS, XPS, EPR and PL. All photocatalysts showed broad-spectrum activity due to their strong absorption in the UV region and some absorption in the visible region. The morphology of the materials was highly influenced by the synthesis temperature and time, which affected the photocatalytic efficiency. All materials exhibited good photocatalytic activity under simulated sunlight, with maximum acetaminophen removal of 99.6% for the catalyst synthesized at 120 °C and 12 h. Stability tests showed considerable stability after four cycles. The main reactive species participating in the photodegradation reaction were found to be O2•-> h+ ∼ •OH. The heterojunction formed between AgCl and WO3 plays an important role in the photocatalytic activity, especially when the AgCl surface is not completely covered by WO3.