An Mn2+-mediated construction of rhombicuboctahedral Cu2O nanocrystals enclosed by jagged surfaces for enhanced enzyme-free glucose sensing

Abstract

A rhombicuboctahedral (26-facet) Cu₂O single crystal, generally with well-developed {100}, {110} and {111} crystallographic planes, has attracted considerable attention due to its faceted synergistic effects in catalysis, sensing, and energy conversion. However, the electrocatalytic performance of the 26-facet Cu₂O single crystal can be severely limited by its large size and low-active smooth surface, since it is quite difficult to prepare high-active 26-facet Cu₂O nanocrystals exposed with rough surfaces. In this article, we successfully prepared jagged 26-facet Cu₂O nanocrystals with clean facets at room temperature via a facile Mn²⁺ mediated aqueous phase reduction method. The shape-evolution and growth mechanism of rhombicuboctahedral Cu₂O nanocrystals enclosed by jagged surfaces are also proposed, which might be attributed to a sequential dissolution–precipitation–surface reforming mechanism. These unique jagged 26-facet nanocrystals exposed with more active sites can exhibit superior glucose-sensing performance than those of the traditional 26-facet Cu₂O microcrystals enclosed by smooth surfaces. With the merits of facile control as well as relatively high activity, it could provide a good prospect for the surfactant-free synthesis of other metal oxides with well-defined crystal planes.