3DOM preparation

Sadakane, M., Asanuma, T., Kubo, J. et al. (2005) Facile procedure to prepare three-dimensionally ordered macroporous (3DOM) perovskite-type mixed metal oxides by colloidal crystal templating method, Chem. Mater. 17, 3546. 

Recently, the LbL technique has been extended from conventional nonporous substrates to macroporous substrates, such as 3DOM materials [58,59], macroporous membranes [60-63], and porous calcium carbonate microparticles [64,65], to prepare porous PE-based materials. LbL-assembly of polyelectrolytes can also be performed on the surface of MS particles preloaded with enzymes [66,67] or small molecule drugs [68], and, under appropriate solution conditions, within the pores of MS particles to generate polymer-based nanoporous spheres following removal of the silica template [69]. 

Perovskite mixed metal oxide ABO3 exhibits many interesting and intriguing properties from both the theoretical and the application point of view described in other chapters in this book. Recently, much attention has been paid to the preparation of 3DOM perovskite mixed metal oxides in order to enhance their performances. At present, most attention has been paid to the enhancement of catalytic activities of perovskite mixed metal oxides [9]. 

DOM materials are prepared using colloidal crystal templates [2-8]. The colloidal crystal (opal structure) templates consist of monodispersed spheres with face-centered closed (fee) packing. When 3D network of voids in colloidal crystals is filled by targeted materials and subsequentiy the colloidal crystals are removed, a replica of the colloidal crystal (inverse opal structure) is produced (Figure 6.2). 

Preparation of 3DOM Perovskite Mixed Metal Oxides... 

Perovskite mixed metal oxides are prepared by solid-state reactions and solution methods. In the solid-state reaction, mixtures of precursors (metal oxides or carbonates) are calcined at near 1000 °C. There has been no report to prepare 3DOM perovskite mixed metal oxides by the solid-state reaction. It is difficult to fill the nanometer-scale voids in the template with solid precursors. 

We reported that 3DOM LaMn03 was prepared using La(N03)3 2ind Mn (N03)2 dissolved in ethylene glycol-MeOH mixed solution (entry 14). Infiltration of the solution and subsequent calcination at 700 °C produced 3DOM LaMnOs [30]. 

We reported that 3DOM Lai Sr, Fe03 (x = 0—0.2) was prepared using a mixed metal nitrate solution in mixed solvent of ethylene glycol and MeOH (entry 26) [41,42]. We reported that 3DOM LaFeOs prepared by our ethylene glycol-MeOH mixed solvent method showed higher catalytic activity for soot... 

We reported that 3DOM LaA103 was prepared using a precursor solution of La (N03)s and Al(NOs)3 dissolved in eth)dene glycol and MeOH (entry 42) [30]. 

Preparation of 3DOM LaFeOs with Different Pore Sizes... 

Diameters of 3DOM LaFeOs were tunable by changing PMMA sphere diameters. 3DOM LaFeOs was prepared by using PMMA templates with diameters of 183,268,277,291,413, and 444 nm. It is also possible to use PS instead of PMMA. 

Figure 6.8 Incremental intrusion spectra of Hg porosimetry of (open squares) nonporous LaFe03 prepared without PMMA template and (open circles) 3DOM LaFe03 prepared using PMMA (diameter 268 nm).

Figure 6.9 TEM images of 3DOM LaFe03 prepared using PMMA (diameter 268 nm).

In situ PMMA-templating preparation and excellent catalytic performance of C03O4/ 3DOM Lao.6Sro,4,Co03 for toluene combustion. AppL Catal. A Gen., 458,... 

Sadakane, M., Sasaki, K., Nakamura, H., Yamamoto, T., Ninomiya, W., and Ueda, W. (2012) Important property of polymer spheres for the preparation of three-dimensionally ordered macroporous (3DOM) metal oxides by the ethylene glycol method the glass-transition temperature. Langmuir, 51, 17766-17770. 

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