Preparation of three-dimensional ordered macroporous SiCN ceramic using sacrificing template method

Three-dimensional (3D) long range well. ordered macroporous SiCN ceramics were prepared by infiltrating sacrificial colloidal silica templates with the low molecular weight preceramic polymer, polysilazane. This was followed by a thermal curing step, pyrolysis at 1250 degrees C in a N-2 atmosphere, and finally the removal of the templates by etching with dilute HF. The produced macroporous SiCN ceramics showed high BET surface areas (pore volume) in the range 455 m(2)/g (0.31 cm(3)/g)-250 m(2)/g (0.16 cm(3)/g) with the pore sizes of 98-578 nm, which could be tailored by controlling the sizes of the sacrificial silica spheres in the range 112-650 tim. The sphere-inversed macropores were interconnected by 50 +/- 30 nin windows and 3-5 nm mesopores embedded in the porous SiCN ceramic frameworks, which resulted in a trimodal pore size distribution. The surface of the achieved porous SiCN ceramic was then modified by Pt-Ru nanoparticle depositing under mild chemical conditions. (c) 2005 Elsevier Inc. All rights reserved.