Denitration Catalyst Properties of Dense Packed Meso-porous Silica Compact without Inter-particles Macro-pore Prepared by Ultra High Pressure Isostatic Pressing

Meso-porous silica, which has uniform pores with a diameter of single nanometer, has been applied to various advanced functional materials, such as catalysts and molecular separation membranes. Since this material generally forms particulates with a diameter larger than several micron meters, micrometerscale intra-particle pores exist in a compact and a layer of this material, and therefore the function of the mesopore is not sufficiently desplayed. In this paper, densely packed meso-porous silica powder compact without intra-particles pores was prepared by an isostatic pressing at ultra-high pressure of up to 0.95GPa. Since organic template material is capable of protecting the fracture of meso-pore structure during high pressure isostatic pressing, the meso-pore with a diameter of about 3nm completely remained in the dense compact. After the calcinations at 823K for 6hr to decompose and remove organic template in meso-pore, platinum-particle impregnated meso-porous silica was prepared by soaking it with platinum aqueous solution followed by the calcination at a temperature between 773 and 873K. Since the volume of inter-particles pores were reduced by the ultrahigh pressure isostatic pressing, the grain size of platinum particles on the compact was reduced down to single nm in diameter and the denitration catalyst activity was enhanced.