Cuprous oxide (Cu2O) possesses special optical, photoelectric and catalytic properties and it is widely used as a raw material in paints, glass and ceramics industries, and as a catalyst in agriculture and organic chemical industries. Specifically, it is used as a fungicide in orchards. Meanwhile, research works are under way to use it as a poison in the production of antifouling coatings against marine organisms such as mussels and scallops attached to marine structures like ships.
According to the literature, Cu2O is mainly prepared by wet chemistry, electrochemistry, radiation irradiation, polyol, etc. In these methods, operation is complicated and a number of wastes harmful to the environment are released during reactions. Hence, preparation of cuprous oxide by mechanochemical method, a simple and environmentally friendly preparation method, is being investigated.
Mechanochemistry studies physicochemical changes and reactions when energy by mechanoaction is given to the material. In other words, mechanical energy is converted to chemical energy that is needed to drive a thermodynamically impossible reaction with △G>0. Therefore, mechanochemical reactions have some features that are different from ordinary chemical reactions, and the reaction mechanism and thermodynamic and kinetic features are also significantly different from ordinary thermochemical reactions.
Several kinds of reducing agents including sodium sulfite, hydrazine, sodium hypophosphite, sodium borohydride, glucose, etc. are used to prepare cuprous oxide from copper compounds. All of them except glucose are environmentally harmful or hard to purchase. Meanwhile, few reports are related to the preparation of cuprous oxide from copper sulfate by mechanochemical method.
Kim Yong Chol, a researcher at the Faculty of Chemistry, investigated the possibility of preparing cuprous oxide ultrafine particles by the soft mechanochemical method in which copper sulfate and sodium hydroxide were mixed and glucose and sodium dodecyl sulfate (SDS) were added as a reducing agent and a dispersing agent, respectively, before undergoing milling. Then, he observed the effects of reaction time and molar ratio of sodium hydroxide and copper sulfate on the preparation of Cu2O by this method.
He found that cubic ultra-fine cuprous oxide with good dispersion property and initial particles of 36nm can be prepared when the additive amount of sodium hydroxide is 1.2 times as much as the theoretical value and the crushing time is 30 minutes.
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