Formation of Cu(2)O Solid Solution via High-Frequency Electromagnetic Field-Assisted Ball Milling: The Reaction Mechanism

The contamination of environmental water with organic pollutants poses significant challenges for society, and much effort has been directed toward the development of catalysts and methods that can decompose these pollutants. While effort has been directed toward the fabrication of Cu(2)O catalysts by ball milling, this technique can involve long preparation times and provide low yields. In this study, we synthesized a solid solution of Cu(2)O in 22 h by high-frequency electric-field-assisted ball milling below 40 °C in only one step under aqueous conditions. We investigated the catalytic activities of the produced Cu(2)O solid solution in the microwave-assisted degradation of dyes, namely rhodamine B, phenol red and methyl orange. The prepared Cu(2)O solid solution was very catalytically active and completely degraded the above-mentioned dyes within 2 min. The one-dimensional diffusion model and the phase boundary (planar) model were found to describe the kinetics well. Synergism between ball milling and the high-frequency electromagnetic field plays a key role in the preparation of Cu(2)O solid solution nanoparticles. Ball milling facilitates the relaxation of the Cu(2)O lattice and high-frequency electromagnetic radiation accelerates the diffusion of Fe atoms into the Cu(2)O crystal along the (111) crystal plane, quickly leading to the formation of a Cu(2)O solid solution.