Copper oxide (CuO) nanoparticles have considerable attention their unique properties and potential for advanced sustainable applications in electronics, energy storage, catalysis, environmental remediation, biomedical applications, and sensing. This review focuses on the synthesis, characterization, and sustainable applications of CuO nanoparticles update serving as a concise and informative resource. The synthesis methods, physical, chemical, and green, sustainable synthesis methods such as biosynthesis, plant extracts, and green chemistry, each offer distinct approaches to creating materials and compounds with varying degrees of environmental impact, efficiency, and applicability in diverse fields ranging from medicine to materials science. Variations and discrepancies in interpretation may arise from different experimental conditions, sample preparation methods, and data analysis approaches, challenging the consensus and comparability of results obtained using various characterization techniques for CuO nanoparticles. Addressing these variations through standardization and understanding the limitations of each technique are crucial for reliable characterization. The review also highlighted the importance of sustainable applications of CuO nanoparticles including their use in energy storage, catalysis, wastewater treatment, and biomedicine. Further research is needed to optimize the synthesis methods of CuO nanoparticles, assess their potential toxicity and environmental impact, and develop standardized characterization techniques. These efforts will enhance their performance, ensure their safe use, and enable sustainable applications across various fields.

Graphical abstract