Abstract
The numerous applications of copper oxide nanoparticles in different fields of science, industries, and research institutions have greatly benefited from recent advances in science and technology. The fabrication of copper oxide nanoparticles, which are brownish-black powders, has received increased attention from researchers owing to their applicability in modern technology. As a result of their versatile qualities, copper oxide nanoparticles are increasingly being used in a variety of applications such as semiconductors, biomedicines, field emission, gas sensors, and solar energy transformers. Its strong activity and efficiency in oxidation and reduction processes have brought about its frequent application as a potent heterogeneous catalyst. However, these widespread applications have increased the level of human exposure, thus increasing the possibility of harm from their shortand long-term intoxications. In this study, the theory, as well as the research state of the various manufacturing processes of the copper oxide nanoparticles, have been emphatically researched and reported to further enhance its application processes within the industry and academia.