Preparation of Ni/SiO₂ fiber catalysts for steam reforming of glycerol

Abstract

This work is aimed to prepare nickel/silica fiber catalyst for steam reforming reaction of glycerol. The nickel/silica fiber catalyst was prepared by a sol-gel and electrospinning technique and then the silica fiber was impregnated by nickel solution. The effects of processing parameters on the morphology of silica fibers such as spinning voltage and the tip to collector distance were studied. The catalysts were characterized by SEM, EDS, TEM, XRD, and TPR. SEM results showed that the average diameter of silica fiber prepared by the applied voltage 15 kV and tip to collector distance 25 cm was the smallest of 0.93 µm. The amount of Ni measured by EDS technique was close to that of Ni loaded by impregnation. The XRD pattern of nickel/silica fiber catalyst showed the amorphous structure of pure silica fibers and the crystalline structure for nickel. The catalyst activity tests on glycerol steam reforming reaction were studied. The reaction parameters such as temperature, feed flow rate, water/glycerol mole ratio, the nickel content, and the additional cerium were investigated. The fiber catalyst showed the higher glycerol conversion compared with the porous catalyst at the same reaction condition and produced H2 and CO as main products whereas the porous catalyst produced H₂ and CO₂ as main products. This can be attributed to the different silica support adsorbing water differently. The silica fiber support adsorbed water lower than the porous support thus the fiber catalyst may not have the water molecules enough to react with CO by water gas shift which converted CO and water into CO₂ and H₂. Therefore the fiber catalyst produced H₂ and CO as the main products.