Efficient dye removal via self-supported Bi2MoO6/CF: PMS activation mechanism and photodegradation pathway

Abstract

The practical application of photocatalytic peroxymonosulfate (PMS) activation systems faces challenges due to the low recyclability of powder catalysts and inefficient charge carrier utilization. In this study, a self-supported Bi₂MoO₆/carbon fiber (CF) composite was designed by growing vertically aligned Bi₂MoO₆ nanosheets on CF through a solvothermal method. The optimized catalyst has been shown to achieve 98.2% Rhodamine B (RhB) degradation within 20 min under visible light in the presence of PMS, displaying a reaction rate constant (0.18 min^-1) that is 2.6 times higher than that of pure Bi₂MoO₆ (0.07 min^-1). The CF substrate has been demonstrated to enhance charge separation efficiency and enable simple catalyst recovery, with 87.3% degradation efficiency being retained after 5 reuse cycles. Mechanistic studies have been conducted to elucidate the cooperative action of sulfate (·SO₄^-), hydroxyl (·OH), and superoxide (·O₂^-) radicals, while degradation intermediates have been shown to reveal two key pathways involving demethylation and structural fragmentation. This work provides a scalable strategy to develop stable photocatalytic systems that combine rapid pollutant removal with practical reusability, advancing PMS-based technologies for practical application in water treatment.