Visible-light responsive CuO-ZnO nanostructure synthesized using Muntingia calabura extract for efficient H2O2 evolution and organic pollutant degradation

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Physicochemical and engineering aspects, 2024-11, Vol.700, p.134741, Article 134741
• Main Authors: Huong, Le Minh, An, Hoang, Dat, Nguyen Minh, Nam, Nguyen Thanh Hoai, Hung, Phan Nguyen Phu, Minh, Nguyen Cong Anh, Hai, Nguyen Duy, Vu, Nguyen Hung, Dat, Nguyen Tien, Nhung, Tran Nguyen Cam, Tan, Pham Truong, Hieu, Nguyen Huu
• Format: Article
• Language: English
• Subjects: absorption; aeration; clean energy; Copper oxide; cost effectiveness; dielectric spectroscopy; electron microscopy; Fourier transform infrared spectroscopy; Hydrogen peroxide; leaf extracts; light; Malachite green; Muntingia calabura; nanospheres; oxygen; photocatalysis; photolysis; pollutants; Raman spectroscopy; remediation; Tetracycline; ultraviolet-visible spectroscopy; voltammetry; X-ray diffraction; Zinc oxide
• ISSN: 0927-7757
• DOI: 10.1016/j.colsurfa.2024.134741

In this study, ZnO-CuO heterostructures were synthesized via a green approach using Muntingia calabura leaf extract with insights into the precursor ratio for enhanced photocatalytic performance. The synthesized materials were characterized by modern analytic methods, including X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, ultraviolet-visible absorption spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry, which elucidated the presence of CuO nanospheres and ZnO semi-cuboids. Thanks to a lower bandgap of 2.24 eV compared to pristine ZnO (2.82 eV), better visible light absorption, and longer charge lifetime, the optimal ZC16 sample, corresponding to a Cu:Zn ratio of 1:16, achieved a hydrogen peroxide production of 350.23 μM under visible light that was further increased to 478.98 μM with oxygen aeration. In addition, ZC16 also demonstrated excellent photodegradation performance towards malachite green (95.82 %) and tetracycline (97.78 %). Disclosure into the photocatalytic mechanism of both processes revealed the significant roles of active radicals, which have proven the environmentally friendly and cost-efficient synthesis pathway of ZnO-CuO heterostructures for environmental remediation and clean energy applications. [Display omitted]