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In this paper, flexible mesoporous Si-doped Al 2 O 3 ultrafine fibers were successfully prepared by electro-blow spinning (EBS) technology followed by a calcination process. The effects of spinning parameters, including air pressure, voltage, and solution injection rate on the morphology and diameter of fibers were investigated. The results showed that the spinning parameters played a key role on determining the morphology and diameter of fibers, and the specific surface area of fibers significantly increased with the increasing content of pore forming agents (polytetrafluoroethylene, PTFE), at the same time the pore size distribution was mainly concentrated at ~5 nm. Most importantly, Si(OC 2 H 5 ) 4 was introduced to act as the flexible regulator which could inhibit the growth of alumina crystal, decrease the crystal size, and thus the flexibility of obtained mesoporous Si-doped Al 2 O 3 ultrafine fibers can be improved. Moreover, the fibers productivity by EBS method was higher than that of traditional electro-spinning. In the future, the mesoporous Si-doped Al 2 O 3 ultrafine fibers may perform desired function and spread their applications in different areas. [ABSTRACT FROM AUTHOR]

Abstract Al 2 O 3 fibers, especially with unique morphology and structure, are a fascinating class of ceramics that have been widely used as catalyst supports. In this work, smooth, porous and needle-like Al 2 O 3 fibers are successfully prepared by electro-blowing spinning (EBS) method. Effects of calcination temperature, calcination rate and pore forming agent content (Polytetrafluoroethylene, PTFE) on the morphology and structure of Al 2 O 3 fibers are systematically studied. Most importantly, Al 2 O 3 fibers with different morphologies are particular suitable to be used as CuO supports for selective oxidation of 5-hydroxymethyl-2-furfural (HMF) to 2,5-furandicarboxylic acid (FDCA). Benefiting from the unique structure, FDCA synthesis over the needle-like CuO/Al 2 O 3 fibers achieves 98.6% yield, which is much higher than the yields over smooth and porous CuO/Al 2 O 3 fibers. Moreover, the fiber catalysts could be easily recovered and reused without the loss of its activity. It is anticipated that Al 2 O 3 fibers with needle-like mullite will shed some light on the development of profiled ceramic fibers for various applications. [ABSTRACT FROM AUTHOR]