In recent years, achieving a cleaner water goal has become increasingly difficult due to the rising complexity of industrial pollutants. This study approaches the need for an advanced and sustainable wastewater treatment method by developing a high-performance nano Cu2O/CuO heterojunction. This nano catalyst has been synthesized in a facile, one-pot green medium using Kahwa tea leaf extracts as reducing, stabilizing, and capping agents. In comparison to the traditional single-component oxides, this biogenic mixed-phase nano system demonstrates a superior charge separation and rapid degradation kinetics under ambient light without the need for high-intensity external radiation. A comprehensive characterization was performed with UV-Vis spectroscopy, FT-IR, FE-SEM/EDS, HR-TEM, XRD, and Zeta potential, which confirmed a polycrystalline structure of the nanoparticles with a mean crystallite size of 23.5 nm. The Cu 2 O/CuO nano catalyst is characterized as a type II (p-p) heterojunction in which a cubic cuprous oxide with an optical bandgap of 2.93 eV coexists with a monoclinic cupric oxide phase with an optical bandgap of 1.93 eV. The synthesized nanoparticles demonstrated exceptional catalytic efficiency by achieving 95.1% degradation of Methylene Blue and 81.0% of Methyl Orange in just 20 to 25 minutes, adhering to the pseudo-second-order kinetics. A defining highlight of this research is the unprecedented stability of the catalyst, which maintained its performance for up to 11 consecutive cycles for Methylene Blue and 8 cycles for Methyl Orange. By combining minimal chemical usage, rapid reaction rates, and industry-leading reusability, this work establishes a highly sustainable and economical standard for advanced future industrial wastewater remediation. • First microwave green synthesis of Cu 2 O/CuO heterojunctions via Kahwa tea extract. • Photocatalytic removal of MB (>95%) and MO (>81%) without light. • Nanoparticles exhibit high performance across a broad pH range. • Cu(I)/Cu (II) redox cycling drives the generation of reactive oxygen species. • Outstanding and stable reusability of NPs for up to 11 cycles.
Kumari et al. (Wed,) studied this question.