In-Situ Hydrothermal Construction of Ag2S/CN Composite Photocatalyst for Superior Degradation of Methyl Orange in Aqueous Solution

The present work constructs a novel Ag₂S/CN composite photocatalyst via in-situ hydrothermal method. The photocatalytic performance of the obtained Ag₂S/CN composite was meticulously evaluated through the degradation of methyl orange (MO) under visible light irradiation. Compared to pure CN and Ag₂S, the Ag₂S/CN composite exhibited significantly enhanced photocatalytic performance. Specifically, the optimal Ag₂S/CN (0.4) sample achieved activities that were 70 and 5 times higher than those of Ag₂S and CN, respectively. This remarkable enhancement can be attributed to the reduced band gap and expanded light absorption range of CN when combined with Ag₂S. Additionally, the surface plasmon resonance (SPR) effect of Ag 0 nanoparticles generated during photodegradation further improves photocatalytic performance by facilitating the separation of photogenerated carriers. Based on photoelectrochemical properties and active species trapping experiments, a plausible mechanism involving hydroxyl radicals (·OH) and superoxide radicals (·O₂⁻) is proposed. The combination of wide-bandgap and narrow-bandgap semiconductors offers a promising strategy for developing efficient photocatalysts for wastewater treatment.