Ru-Doped Cobalt−Zirconia Nanocomposites by Flame Synthesis: Physicochemical and Catalytic Properties

Abstract

Nanocomposites of Ru-doped cobalt-zirconia (20 wt % Co) were made by rapid and scalable flame spray pyrolysis (FSP). They were characterized by nitrogen adsorption, X-ray diffraction, electron microscopy, and X-ray photoelectron spectroscopy revealing that cobalt clusters were highly dispersed within the zirconia matrix. Adding traces of Ru (0.04 and 0.4 wt %) to this unique structure during FSP significantly lowered the two-step reduction temperature of Co 3 O 4 to CoO and metallic Co 0 , further resulting in a 4-fold increase in CO chemisorption compared to undoped ones. The catalytic properties of the nanocomposites were further studied in a Fischer-Tropsch reaction and compared to those prepared by incipient wetness impregnation and mechanical mixing. The enhanced reducibility and CO chemisorption through doping with 0.4 wt % Ru was highly beneficial to the catalytic property of the flame-made composites.

Photocatalytic mineralisation of organic compounds: a comparison of flame-made TiO2 catalysts

“…XRD crystallite size analysis for both TiO 2 samples (Table 1) revealed a difference in the size of their respective rutile and anatase crystals. Earlier studies by Teoh et al [10] have found that FSP-made anatase and rutile particles exist as separate crystallites. Hence from the TEM images in figures 1(a) and (b), the larger spherical particles ($18 nm) are likely to be anatase while the smaller ones ($9 nm) are believed to be rutile, in agreement with the XRD-determined crystallite size.…”

“…A detailed description on the synthesis of TiO 2 particles by FSP can be found in Teoh et al [10]. Briefly, a mixture of titanium isopropoxide (TTIP, Aldrich, purity > 97%) /xylene (Riedel deHaen, 96%)/acetonitrile (Fluka, 99.5%) in the volume ratio of 20/55/25, respectively, was used as the precursor.…”

“…The FSP-made TiO 2 photocatalyst used here has been earlier found to be the optimal photocatalyst for mineralisation of sucrose [10]. In this paper, the same photocatalyst is further tested for a wider range of organic compounds accompanied by additional extensive particle characterisation and reactive system analysis.…”

“…Recently TiO 2 photocatalyst has been synthesised via a rapid flame spray pyrolysis (FSP) technique [10]. Titanium isopropoxide (TTIP) in xylene/acetonitrile solvent mixture was dispersed and combusted in an oxygen rich flame yielding fine TiO 2 nanoparticles.…”

Titania and titania-silver nanoparticle deposits made by Liquid Flame Spray and their functionality as photocatalyst for organic- and biofilm removal

“…Most of the present studies in this area concentrate on multicomponent nanoparticles or deposits production [2][3][4][5][6][7][8][9][10][11][12]. Titania is well known for its photocatalytic properties [13][14][15].…”