Mesoporous crystalline metal oxide

GENERATION OF MESOPOROUS CRYSTALLINE METAL OXIDE FILMS VIA EVAPORATION-INDUCED SELF-ASSEMBLY... 

Ordered mesoporous crystalline metal oxides have been synthesised using template methods, which are generally divided into the soft template method and the hard template method , depending on the nature of the templates. 

Thermally Stable and Highly Crystalline Mesoporous Transition Metal Oxides... 

In order to elucidate the importance of the role of in situ formed carbon in the formation of well-organized, highly crystalline mesoporous transition metal oxides, as-synthesized Ti02 was directly calcined under air to 700°C while keeping all other conditions the same as for the CASH method. As expected, the BET surface area of the resulting material was only 0.2 m2 g-1 and no porous structure could be detected by TEM imaging. This implies that the mesostructure completely collapsed. The crystallite size of this sample, heat treated to 700°C in air is 31.5 nm (calculated... 

J. W. Lee, M. C. Orilall, S. C. Warren, M. Kamperman, F. J. Disalvo and U. Wiesner, Direct access to thermally stable and highly crystalline mesoporous transition-metal oxides with uniform pores, Nat. Mater., 7, 222-8(2008). 

The number of publications concerning utilization of the EISA process for fabrication of different structured materials is counted in the hundreds, which is far beyond the possibilities of this chapter to review in depth. Rather, we intend to provide a brief introduction into EISA and its application to the fabrication of functional thin films for electronic applications (e.g., electro-chromic layers and solar cells), with a special focus on fabrication of crystalline mesoporous films of metal oxides. Attention will also be given to techniques used to evaluate the pore structure of the thin films. For the other aspects of the EISA process, for example its mechanism,4 strategies for preparation of crystalline porous metal oxides,5 mesoporous nanohybrid materials,6 periodic organic silica materials,7,8 or postgrafting functionalization of mesoporous framework,9 we kindly recommend the reader to refer to the referenced comprehensive reviews. 

Brezesinski, T. Smarsly, B. Iimura, K. Grosso, D. Boissiere, C. Amenitsch, H. Antonietti, M. Sanchez, C. 2005. Self-assembly and crystallization behavior of mesoporous, crystalline Hf02 thin films A model system for the generation of mesostructured transition-metal oxides. Small 1 889-898. 

Brezesinski, T. Antonietti, M. Smarsly, B. M. 2007. Self-assembled metal oxide bilayer films with single-crystalline overlayer mesopore structure. Adv. Mater. 19 1074-1078. 

Mesoporous materials with a transition metal oxide framework have immense potential for applications in catalysis, photocatalysis, sensors, and electrode materials because of their characteristic catalytic, optical, and electronic properties. However, for some applications, this potential can only be maximized in the highly crystalline... 

Some important metal oxide materials that have used molecular and supramole-cular templates to direct structure formation are the zeolites and related semi-crystalline aluminosilicates. In this section we shall discuss the use of ammonium cations that direct formation of microporous zeolites and finish with some of the possibilities that exist with the use of surfactant systems and molecular aggregates to create mesoporous structure. Excellent books and reviews are suggested for additional reading into the detailed description of the art [58-60]. The intention of this section is to briefly introduce this area and describe the types of materials being produced using various imprinting techniques in metal oxide materials. 

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