Advanced Functional Materials

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17_15b/2007Inside Front Cover: One-Pot Synthesis and Hierarchical Assembly of Hollow Cu2O Microspheres with Nanocrystals-Composed Porous Multishell and Their Gas-Sensing Properties (Adv. Funct. Mater. 15/2007)

On p. 2766, Qinshan Zhu and co-workers report on multishell hollow Cu2O microspheres that are synthesized by a facile and one-pot solvothermal route. A two-step organization process, in which hollow microspheres of Cu2(OH)3NO3 are formed first followed by reduction to Cu2O by glutamic acid, leads to the special multishell and hollow microstructures. Interestingly, a Cu2O gas sensor fabricated with the multishell microspheres shows a much higher sensitivity to ethanol than solid Cu2O microspheres.

Hierarchical assembly of hollow microstructures is of great scientific and practical value and remains a great challenge. This paper presents a facile and one-pot synthesis of Cu2O microspheres with multilayered and porous shells, which were organized by nanocrystals. The time-dependent experiments revealed a two-step organization process, in which hollow microspheres of Cu2(OH)3NO3 were formed first due to the Ostwald ripening and then reduced by glutamic acid, the resultant Cu2O nanocrystals were deposited on the hollow intermediate microspheres and organized into finally multishell structures. The special microstructures actually recorded the evolution process of materials morphologies and microstructures in space and time scales, implying an intermediate-templating route, which is important for understanding and fabricating complex architectures. The Cu2O microspheres obtained were used to fabricate a gas sensor, which showed much higher sensitivity than solid Cu2O microspheres.

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