Surface and Structural Features of Co‐Fe Oxide Nanoparticles Deposited on a Silica Substrate

Abstract

Keywords: Cobalt / Iron / Oxides / Metal-metal interactions / Materials science Mono-and dimetallic cobalt-and iron oxide nanoparticles deposited on the surface of a silica substrate have been prepared by an impregnation technique. Both the bulk and surface structures of these particles have been characterised by different physical and chemical techniques. The results provided by X-ray diffraction, Mössbauer and X-ray photoelectron spectroscopy show the formation of separate Co 3 O 4 and Fe 2 O 3 nanoparticles in oxide samples, but in no case were cobalt-iron mixed oxides detected. Quantitative data also showed that the dispersion degree of cobalt-and iron oxides is rather low. It was also observed that pretreatment of the supported metal oxide nanoparticles under a hydrogen atmosphere does not promote the formation of a metal-support

Structural changes and activation treatment in a Co/SiO2 catalyst for Fischer–Tropsch synthesis

“…Preliminary characterization of Co10-c (calcined sample) has already been reported [22]. The XRD pattern indicated the sole presence of Co 3 O 4 cubic phase with a crystallite average size determined using the Scherrer equation of 21 nm.…”

Effect of Manganese on Co–Mn/CNT Bimetallic Catalyst Performance in Fischer–Tropsch Reaction

“…Split in binding energy ∆E Co between Co2p 1/2 -Co2p 3/2 was 16.0 eV and satellite peak at +6 eV from Co2p 3/2 were observed. As shown in Figure 11, the Co2p 3/2 peak also consisted of a double, Co 3+ (octahedral environment) at BE = 789.4 eV and Co 2+ (tetrahedral environment) at BE = 788.3-788.6 eV was characteristic of Co 3 O 4 peaks [41,[43][44][45]. For bimetallic catalysts, it was found that Co2p binding energies had shifted to a lower value having nearly the same ∆Eco.…”

Bimetallic catalysts for the Fischer–Tropsch reaction

“…63 However, another study on silica-supported bimetallic calcined samples showed separate Co 3 O 4 and Fe 2 O 3 phases, with no cobalt-iron mixed oxides. 64 After hydrogen reduction at 500 • C, Co 0 and Fe 0 metallic phases formed in monometallic samples, whilst bimetallic phases comprised mainly two phases: Co 0 (major phase, 76%) and a CoFe alloy. The crystallite size of the alloyed phase increased with iron content, whereas that of the Co 0 phase remained constant.…”