Two birds with one stone: Facile fabrication of a ternary ZnIn2S4/BiVO4/MWCNTs nanocomposite for photocatalytic detoxification of priority organic pollutants and hydrogen production with a proposed mechanism

A series of ternary nanocomposites with different weight percentages of zinc indium sulfide, bismuth vanadate, and multiwalled carbon nanotubes (ZnIn2S4/BiVO4/MWCNTs) were synthesized using a simple thermal impregnation method to obtain high charge separation and transfer efficiency, thus improving their photocatalytic performance. The 20 wt.% ZnIn2S4/BiVO4/MWCNTs (20 wt.% ZBM) nanocomposite exhibited enhanced photocatalytic activity compared to pure BiVO4 and ZnIn2S4 for the degradation of methylene blue, acetaminophen, and allopurinol in an aqueous solution when exposed to a visible light source and atmospheric oxygen. This nanocomposite demonstrated a particularly high degradation rate constant (k = 6.39 × 10−2 min−1) for the photocatalytic degradation of methylene blue. The introduction of MWCNTs boosted the photocatalytic performance of the 20 wt.% ZBM nanocomposite, attaining a maximum H2 production of 1704 μmol g−1. Repeated photocatalytic H2 generation reached 1621 μmol g−1 after 5 h of irradiation with four consecutive cycles. Therefore, we propose a “two birds with one stone” strategy for greatly improved photocatalytic wastewater detoxification and H2 production by prolonging the lifetime of the photogenerated electron–hole pair separation.