Manipulating the Self-Assembling Process to Obtain Control over the Morphologies of Copper Oxide in Hydrothermal Synthesis and Creating Pores in the Oxide Architecture
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- 作者：Ziyi Zhong ; Vivien Ng ; Jizhong Luo ; Siew-Pheng Teh ; Jaclyn Teo ; Aharon Gedanken
- 刊名：Langmuir
- 出版年：2007
- 出版时间：May 22, 2007
- 年：2007
- 卷：23
- 期：11
- 页码：5971 - 5977
- 全文大小：1126K
- 年卷期：v.23,no.11(May 22, 2007)
- ISSN：1520-5827
文摘
Copper oxide with various morphologies was synthesized by the hydrolysis of Cu(ac)2 with urea under mildhydrothermal conditions. In the synthesis, a series of organic amines with one or two amine groups (monoamine anddiamine), including isobutylamine, octylamine (OLA), dodecylamine, octadecylamine (monoamines), ethylenediaminedihydrochloride, and hexamethylenediamine (diamines), was used as the "structure-directing agent". The monoaminesled to the formation of one-dimensional (1D) aggregates of the copper oxide precursor particles (Pre-CuO), while thediamines led to the formation of two-dimensional (2D) aggregates. In both cases, the shorter carbon-chain aminemolecules showed a stronger structure-directing function than that of the longer carbon-chain amine molecules. Next,in a series of syntheses, OLA was selected for further study, and the experimental parameters were systematicallymanipulated. When the hydrolysis was adjusted to a very slow rate by coupling the hydrolysis reaction with anesterification reaction, 1D aggregates of Pre-CuO were formed; when the hydrolysis rate was in the middle range,spherical Pre-CuO architectures composed of smaller linear aggregates were formed. However, under the high hydrolysisrates achieved by increasing the precipitation agent (urea) or by conducting the reaction at high temperatures (
120
C), only Pre-CuO nanoparticles with a featureless morphology were formed. The formed spherical Pre-CuO architecturescan be converted to a porous structure (CuOx) after removing the OLA molecules via calcination. Compared to the1D and 2D aggregates, this porous architecture is highly thermally stable and did not collapse even after calcinationat 500 C. Preliminary results showed that the porous structure can be used both as a catalyst support and as a catalystfor the oxidation of CO at low temperatures.
120C), only Pre-CuO nanoparticles with a featureless morphology were formed. The formed spherical Pre-CuO architecturescan be converted to a porous structure (CuOx) after removing the OLA molecules via calcination. Compared to the1D and 2D aggregates, this porous architecture is highly thermally stable and did not collapse even after calcinationat 500 C. Preliminary results showed that the porous structure can be used both as a catalyst support and as a catalystfor the oxidation of CO at low temperatures.