Diethanolamine Reduction Route to Shaped Cuprous Oxide

A diethanolamine reduction strategy has been successfully developed for the first time to synthesize cuprous oxide crystals with various shapes in an aqueous/aqueous-ethanol mixed solution system. Nearly monodispersed octahedral, truncated octahedral, and cubic crystals can be directly obtained by adjusting the amount of diethanolamine and ethanol added to the designed reaction solution of copper nitrate and deionized water. The reduction takes place both with nitrate and acetate as counterions, which confirms that diethanolamine plays the role of a reducing agent. The possible formation mechanism for the products with various architectures is proposed, which is mainly based on the variation of the ratio (R) of growth rates along both 〈100〉 and 〈111〉 directions. It has revealed that the diethanolamine and ethanol have a synergistic effect on stabilizing the {100} facets and thus stimulate the preferential growth of cuprous oxide. This effective synthetic route may shed some light on the design of shape-controlled reduction-related synthesis of other promising nano- to micro-scale materials.