DISPERSED NOBLE METAL-CONTAINING ALUMINA PARTICLE, ITS PREPARATION PROCESS AND EXHAUST GAS PURIFICATION CATALYST

摘要

PROBLEM TO BE SOLVED: To provide an exhaust gas purification catalyst which is prepared by using a noble metal and a carrier consisting of hollow particles and in which the noble metal can effectively be utilized. SOLUTION: This catalyst preparation process comprises dispersing an aqueous solution which consists essentially of the Al element and also contains at least one noble metal in an organic solvent to form a W/O(water-in-oil) type emulsion, subjecting the W/O type emulsion to atomized combustion to form hollow particles, and then subjecting the hollow particles to heat treatment at 950-1200 deg.C in a non-oxidizing atmosphere. By the heat treatment, θ- or α-phase Al2O3 (alumina) is partly formed to expose noble metal particles buried in an amorphous phase, and the degree of dispersion of the noble metal in the hollow particles, measured by a CO adsorption method, is >=10%.