Bismuth Sulfide Doped in Graphitic Carbon Nitride Degrades Nitric Oxide under Solar Irradiation

This study developed and examined the application of bismuth sulfide doped on graphitic carbon nitride (Bi₂S₃@g-C₃N₄) in the degradation of NO under solar irradiation. Bi₂S₃@g-C₃N₄ was prepared through the calcination method. The morphological structure and chemical properties of the synthesized photocatalyst were analyzed before the degradation tests. After doping with Bi₂S₃@g-C₃N₄, the bandgap was reduced to 2.76 eV, which increased the absorption of solar light. As a result, the Bi₂S₃@g-C₃N₄ achieved higher NO degradation (55%) compared to pure Bi₂S₃ (35%) and g-C₃N₄ (45%). The trapping test revealed that the electrons were the primary species responsible for most of the NO degradation. The photocatalyst was stable under repeated solar irradiation, maintaining degradation efficiencies of 50% after five consecutive recycling tests. The present work offers strong evidence that Bi₂S₃@g-C₃N₄ is a stable and efficient catalyst for the photocatalytic oxidation of NO over solar irradiation.