POROUS OXIDE SEMICONDUCTOR PARTICLES

Porous oxide semiconductor particles have a connected structure in which porous primary particles having an aggregate of crystallites composed of an oxide semiconductor are connected to each other and have a specific surface area of 60 m/g or more. The porous oxide semiconductor particles have preferably a pore diameter of 1 nm or more and 20 nm or less. The porous oxide semiconductor particles have preferably a tap density of 0.005 g/cmor more and 1.0 g/cmor less. The oxide semiconductor is preferably SnOor SnOdoped with at least one element selected from the group consisting of Nb, Sb, W, Ta, and Al.