Controlled synthesis of concave Cu2O microcrystals enclosed by {hhl} high-index facets and enhanced catalytic activity

Abstract

Due to the fact that crystal facets with high surface energy usually exhibit superior performance in many fields, such as catalysis, the importance of the synthesis of micro/nano-crystals with exposed high surface energy facets is becoming a hot research field. In this article, concave Cu₂O microcrystals mainly enclosed by {hhl} high-index facets have been successfully prepared by reducing Cu(CH₃COO)₂ with glucose in the presence of sodium dodecyl sulphate (SDS). SDS was proved to be important in the formation of the concave Cu₂O microcrystals. The concave degree of truncated octahedra can be controlled by adjusting the concentration of SDS. In addition, we found the reaction rate also affected the morphology of Cu₂O microcrystals. Octahedron-based branched particles, truncated concave octahedra and truncated octahedra can be obtained by adjusting the concentration of glucose. In the catalytic oxidation of CO, truncated concave octahedral Cu₂O enclosed by {332} high-index facets exhibited the highest catalytic activity among the high-index {332} facets, low index {111} and {100} facets, due to the existence of high density steps on {332} facets and the CO catalytic activities of the crystal facets are in the sequence: {332} > {111} > {100}.