Surfactant-assisted synthesis of bismuth tungstate for dye decolorization under visible light irradiation

　Dyes are highly toxic organic pollutants that are difficult to decompose, causing significant environmental damage. In recent years, research has been conducted on dye degradation using photocatalysis, an environmentally friendly, efficient, and clean pollutant degradation technology. Among photocatalysts, bismuth tungstate (Bi₂WO₆) has been reported to possess photocatalytic activity under visible light irradiation due to its stable physicochemical properties and suitable band gap. However, the narrow light absorption region and high recombination rate of electron–hole pairs require further studies to improve their photocatalytic performance. In this work, the effect of surfactants in synthetic systems on the morphology and photocatalytic activity of Bi2WO6 is investigated .

　Bi₂WO₆ was synthesized by a simple one-pod solvothermal method using ethylene glycol. Various surfactants, including cationic, anionic, and nonionic types, were introduced during catalyst preparation, respectively. The photocatalytic efficiency was evaluated through the decolorization of Rhodamine B as a model dye.

　The decolorization rate of RhB after 120 minutes of light irradiation confirmed that adding surfactants to the synthetic system improved the photocatalytic activity. In particular, high decolorization rates were achieved when cationic (benzalkonium chloride, hexadecyl trimethylammonium bromide) and anionic (sodium oleate) surfactants were used. Various characterizations suggest that the enhanced photocatalytic activity could be attributed to the improved ability to separate and transfer photogenerated carriers.