Photocatalytic degradation of naproxen by Bi2MoO6/g-C3N4 heterojunction photocatalyst under visible light: Mechanisms, degradation pathway, and DFT calculation

[Display omitted] •2D/2D Bi2MoO6/g-C3N4 photocatalyst was synthesized by hydrothermal coprecipitation method.•Bi2MoO6/g-C3N4 exhibited enhanced photocatalytic degradation activity towards naproxen under visible light.•The heterojunction formation promotes the separation efficiency of photogenerated electrons and holes.•The superoxide radicals and holes play dominant role in the photodegradation of NPX.•Degradation pathway was proposed based on the degradation intermediates identified by LC–MS/MS and DFT calculations. In this research, a 2D/2D Bi2MoO6/g-C3N4 heterojunction photocatalyst, which can be driven by visible light, was fabricated through a hydrothermal coprecipitation method. Naproxen was used as the target organic contaminant to evaluate the photocatalytic performance of Bi2MoO6/g-C3N4. The composite photocatalyst showed promoted photocatalytic activity, among which BMO/CN50−50 with a mass ratio 50/50 exhibited the fastest degradation rate, the degradation rate was 3.9 and 2.5 times higher than that of g-C3N4 and Bi2MoO6, respectively. Scavenger experiments and EPR measurements demonstrated that hole (h+) and superoxide radical (O2−) play a leading role in the degradation reactions. Moreover, the degradation pathway was suggested in the light of identified intermediates by Liquid Chromatography-Mass Spectrometry (LC–MS/MS) and DFT analysis. Furthermore, the Quantitative Structure-Activity Relationship (QSAR) analysis was used to evaluate the toxicity of identified degradation intermediates.