Enhancement of photocatalytic activity of ZnO by ZnMoO₄ compositing under visible light via hydrothermal green synthesis

ZnO has excellent photocatalytic activity under UV light, but its photocatalytic activity under visible light is relatively low due to its wide band gap. Modification of ZnO to a composite with ZnMoO₄, which has a band gap energy of 2.61 eV, triggers heterojunction photocatalytic reactions under visible light. Here in this research, ZnO-ZnMoO₄ nanocomposites have been successfully synthesized using the green synthesis hydrothermal method with Mentha × piperita leaf extract containing alkaloids as a source of weak bases and other secondary metabolites as capping agents. The development of green synthesis methods in this study aims to reduce the use of hazardous and toxic materials. The synthesized photocatalysts have been fully characterized and evidence of increased photocatalytic activity of ZnO/ZnMoO₄ composites is based on the degradation of Rhodamine B (RhB) dye in visible light. The results showed that the degradation of RhB by ZnO/ZnMoO₄ nanocomposites could reach 83.7 %, and this was better than using ZnO which only reached 13.9 %.