Patent ID: 7713908

Claim:
A method of producing a porous composite metal oxide comprising the steps of: dispersing first metal oxide powder, which is an aggregate of primary particles each with a diameter of not larger than 50 nm, in a dispersion medium using microbeads each with a diameter of not larger than 150 μm, thus forming first metal oxide particles having an average particle diameter of 1 nm to 50 nm, wherein 80% or more by mass of said first metal oxide particles are 75 nm or smaller in diameter; dispersing and mixing in a dispersion medium said first metal oxide particles and a second metal oxide powder, said second metal oxide powder being an aggregate of primary particles each with a diameter of not larger than 50 nm, and not larger than 200 nm in average particle diameter, thus forming a homogeneously-dispersed solution of the first metal oxide particles and second metal oxide particles; and drying the homogeneously-dispersed solution, thus obtaining a porous composite metal oxide.