Synthesis,transformation to octahedron‐like crystals,and gas‐sensing property of six‐horned nanospheres of Cu2O

Single‐crystal six‐horned nanospheres of Cu₂O with a diameter of 760 nm in average were prepared in aqueous solution of CuCl₂and NaOH by using ascorbic acid as the reductant in the presence of sodium dodecyl benzenesulfonate (SDBS) at room temperature. The horn grows along the <100> direction, which is consistent with the protuberant direction of an apex of octahedron. The formation process of six‐horned nanospheres included two steps: the formation of Cu₂O nanospheres via Ostwald ripening process, and the appearance of horns on the surface of nanospheres under low concentration of SDBS. As increasing the concentration of SDBS, the six‐horned nanospheres could be transformed into octahedron‐like Cu₂O. And at the same concentration of SDBS, keeping the volume ratio of water and ethanol in mixed solutions as 1:1, Cu₂O octahedra were obtained. Moreover, gas‐sensing property showed that six‐horned nanospheres of Cu₂O had higher sensitivity compared with Cu₂O nanospheres and Cu₂O octahedra to ethanol gas (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)