Hierarchically Porous Fiber by Electrospinning and Posttreatment
In addition to ME-ES, other methods can prepare multiporous fibers and demonstrate more advantages. For example, Yong Zhao’s group for the first time prepared a porous hierarchy of TiO2 and SiO2 heterostructured fibers by electrospinning based on the hydrolysis and polycondensation of inorganic alkoxides. The fabrication of porous TiO2-SiO2 fibers is accomplished by singlespinneret electrospinning without using sacrificial templates and special heat treatment. TiO2 and SiO2 composite fibers with narrow mesopores, meso/macropores, and micro/meso/macropores have been obtained, and the factors governing the porous hierarchy have been investigated. Fig. 5.24AeC are TiO2-SiO2 composite fibers with a tunable interconnected porous hierarchy. Mesoporous TiO2-SiO2 fibers exhibit excellent photocatalytic activity in the degradation of rhodamine B, comparable to Degussa P25. The photocatalytic activities of the TiO2-SiO2 fibers may be attributed to the combined merits of mesoporosity, high specific surface area, good adsorption capacity for rhodamine B, and anataseerutile heterojunction. Wang et al. reveals the potential applications for using of hydrolysis and polycondensation of inorganic alkoxides in the preparation of heterostructured inorganic fibers of desired porous structure.