Fabrication and immobilization of heteropoly acids (HPAs) and hexadecyl trimethyl ammonium bromide (CTAB) co-modified ternary zinc indium sulfide (ZnIn2S4): Capture photogenerated electrons and pollutant molecules by co-photocatalyst for enhancing the photocatalytic ability

In this article, a series of HPAs, including phosphotungstic acid (H3PW12O40), silicotungstic acid (H4SiW12O40), phosphomolybdic acid (H3PMo12O40), and hexadecyl trimethyl ammonium bromide (CTAB) co-modified ZnIn2S4 photocatalysts (HPAs/CTAB@ZnIn2S4) were successfully fabricated for the first time by a simple one-pot hydrothermal strategy. As a photogenerated electron capture tool, HPAs and CTAB can capture photogenerated electrons by W 5d (or Mo 4d) unsaturated electron orbitals and quaternary ammonium groups (–N+), thus improving the photogenerated carrier (e––h+) separation efficiency of the main photocatalyst ZnIn2S4. As a pollutant molecule capture tool, HPAs and CTAB can capture pollutant molecules to the surface of photocatalyst through acid-base interaction and hydrogen bonding, so that the target pollutants can be efficiently degraded in the environment of high concentration hydroxyl radicals (·OH). In order to improve the engineering application value of as-prepared photocatalyst, we also successfully fabricated immobilized photocatalyst (H3PMo12O40/CTAB@ZnIn2S4@CC) by using clay ceramsite (CC) as a carrier. The photocatalytic activity of immobilized H3PMo12O40/CTAB@ZnIn2S4@CC is higher than that of H3PMo12O40/CTAB@ZnIn2S4 due to the trapping effect of CC carrier on photons.