Carbon xerogel supported FeWO4/WC S-scheme heterojunction for visible light assisted photo degradation of thiamphenicol

The limited light consumption, fast charge carrier recombination and inadequate redox capacity of typical photocatalysts make visible light-induced photocatalytic degradation of antibiotics difficult. The aim of this work is to design a new S-scheme heterojunction photocatalyst composed of iron tungstate (FeWO 4 ) and tungsten carbide (WC) supported on carbon xerogel (CX) and investigate for the visible-light-driven photodegradation of thiamphenicol (TAP), a persistent veterinary antibiotic contaminant. The FeWO 4 /WC interface facilitated the formation of an S-scheme heterojunction, which promoted efficient charge separation while preserving strong redox potentials. Photoluminescence, electrochemical impedance and photocurrent studies supports the efficient charge separation rate of carriers. Photocatalytic experiments demonstrated that the 1:1 FeWO 4 /WC/CX heterojunction exhibited superior degradation efficiency of 90.61% (at pH-5) within 80 min toward TAP under visible light along with great stability over four cycles. Radical scavenging and ESR studies confirmed the involvement of •OH and •O 2 - radicals in the degradation pathway. In-situ X-ray photoelectron spectroscopy (XPS) provides definitive evidence of charge redistribution at the interface, thereby confirming the S-scheme mechanism. This work highlights the potential of carbon xerogel supported S-scheme heterojunction for the efficient treatment of emerging pharmaceutical pollutants from waste water.