Plasmonic Au@S,O‐GCN/WO ₃ Composite for Photodegradation of RhB Dye

Abstract Water pollution caused by toxic dyes presents a serious environmental challenge requiring sustainable solutions. Pristine graphitic carbon nitride (GCN), a widely studied photocatalyst, is limited by the rapid recombination of electron–hole pairs, which reduces its effectiveness. To address this problem, we explore the photocatalytic potential of a plasmon‐enhanced gold‐decorated sulfur and oxygen co‐doped graphitic carbon nitride–tungsten trioxide (Au@S,O‐GCN/WO 3 ) nanocomposite for photodegradation of RhB dye. The Au@S,O‐GCN/WO 3 nanocomposite was synthesized through a straightforward hydrothermal and solid‐state annealing method, followed by laser ablation. EDS and elemental mapping images confirmed that the gold nanoparticles (AuNPs) and S,O‐GCN were integrated into the GCN matrix. Adding WO 3 and AuNPs greatly improves photocatalytic performance, mainly due to enhanced charge separation. The degradation efficiency of the 10 mg Au@S,O‐GCN/WO 3 photocatalyst reaches 81.25% within 160 min of UV–vis light irradiation, with a rate constant of 0.01 min −1 and a half‐life of 69 min. The photocatalytic mechanism of Au@S,O‐GCN/WO 3 is mainly driven by holes, with secondary involvement from reactive oxygen species. The recycling test shows that the synthesized material can be used multiple times for degradation. These results highlight the potential of Au@S,O‐GCN/WO 3 as an effective photocatalyst for environmental cleanup under UV–vis light.