ScholarWorks@중앙대학교

초록

Industrial discharge of synthetic dyes like malachite green (MG) poses significant environmental hazards due to their toxicity and persistence. Photocatalytic degradation using semiconductor catalysts offers a sustainable remediation approach, yet efficiency is limited by rapid electron-hole recombination. Here we report the phytogenic-assisted synthesis of ZnO/SnO2 hybrid catalysts using Dovyalis abyssinica (D. abyssinica) leaf extract, forming stable heterojunctions with enhanced charge separation and an intermediate band gap of 3.25 eV. Notably, this is the first study to employ D. abyssinica leaf extract as a dual reducing and capping agent for the green synthesis of ZnO/SnO2 heterojunction photocatalysts, enabling controlled interfacial contact and improved charge-transfer efficiency. Structural, morphological, optical, and thermal properties of the catalysts were characterized by XRD, SEM, FTIR, DRS, BET, and TGA–DSC analyses, confirming improved surface properties and thermal stability. Under visible light, the ZnO/SnO2-0.05 hybrid achieved 89.12% degradation of MG within 80 min, outperforming individual ZnO and SnO2 catalysts. Kinetic analysis followed pseudo-first-order behavior, and scavenging experiments identified holes and superoxide radicals as primary reactive species. The catalyst maintained over 70% activity after six reuse cycles. These findings demonstrate the potential of green-synthesized ZnO/SnO2 hybrids as efficient, stable, and reusable photocatalysts for wastewater treatment applications.

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