| abstract |
An object is to provide a silica-based composite oxide fiber which is a continuous fiber high in strength and has, in the fiber surface thereof, mesopores each having an appropriate size, and to provide a catalyst fiber, containing the silica-based composite oxide fiber, in which a noble metal catalyst can be selectively carried into its pores, whereby preventing sintering of the noble metal catalyst. n The silica-based composite oxide fiber comprises a composite oxide phase composed of an oxide phase made mainly of a silica component (first phase) and a metal oxide phase comprising one or more metals other than silica (second phase), wherein a content by percentage of at least one of metal elements of metal oxides constituting the metal oxide phase (second phase) increases with a gradient toward a surface of the fiber, and wherein the metals that constitute the metal oxide phase (second phase) are in the form of particles, and mesopores extending from the fiber surface to the inside of the fiber and having an average pore diameter of 2 to 30 nm are formed between the particles. |