Tungsten disulfide (WS) is a highly active co-catalyst in Fe(III)/HO Fenton-like reactions for efficient acetaminophen degradation.

The most important factor that restricts the decomposition of HO in the Fe/HO reaction is the slow cycling efficiency of reducing Fe to Fe. In this study, the addition of tungsten disulfide (WS) as a co-catalyst achieved a rapid cycling of the reaction rate-limiting step and a significant enhancement of HO decomposition, which resulted in the effective degradation of acetaminophen (APAP). Results show that 99.6% of APAP (5 mg L) could be degraded by HO/Fe/WS system within 2.5 min. The conversion of Fe to Fe occurred mainly on the surface of WS due to the redox reaction of the exposed W active sites with Fe after the unsaturated S atoms were bound to protons. Electron paramagnetic resonance (EPR) and radical quenching experiments evaluated the contribution of hydroxyl radical (•OH) and superoxide radical (O) in the degradation of pollutants. WS showed good recoverability after four cycles of the reaction. This study provides a new perspective to improve the efficiency of Fe/HO and provides a reference for the involvement of transition metal sulfides in advanced oxidation processes (AOPs).