Total Oxidation of Propane Using CeO2 and CuO-CeO2 Catalysts Prepared Using Templates of Different Nature

Abstract

Several CeO 2 and CuO-CeO 2 catalysts were prepared using different methods, i.e., a homogeneous precipitation with urea, a nanocasting route using CMK-3 carbon as a hard template and a sol-gel process using Poly(methyl methacrylate) (PMMA) polymer as a soft template, and tested in the total oxidation of propane. The catalysts were characterized by a number of physicochemical techniques (XRD, N 2 adsorption, TPR, XPS, Raman spectroscopy) showing distinct characteristics. For each series, Cu-Ce-O catalysts with low Cu-loadings (5 wt % CuO) showed the highest activity, higher than those samples either without copper or with high Cu-loading (13 wt % CuO). The incorporation of copper leads to an increase of the concentration of bulk defects but if the Cu-loading is too high the surface area drastically falls. The highest activity in the total oxidation of propane was achieved by Cu-containing ceria catalysts synthesized using a polymer as a template, as this method yields high surface area materials. The surface area and the number of bulk/sub-surface defects of the ceria seem to be the main properties determining the catalytic activity.

Total Oxidation of Naphthalene with Zirconia-Supported Cobalt, Copper and Nickel Catalysts

“…Moreover, the greater metal-zirconia interaction favors the formation of vacancies in the bulk, and consequently, facilitates the movement of oxygen in the catalytic system from the bulk to the surface. A similar effect has been reported for the Cu-CeO 2 system [67]. Finally, reduced sites should be re-oxidized to be regenerate.…”

“…One of the most used mechanisms to explain the catalytic oxidation of hydrocarbons is the Mars-van Krevelen mechanism, where active oxygen comes from catalytic oxide species [14,66]. In this context, Solsona et al [67] carried out the propane oxidation process in oxygen absence using a CuO x -CeO 2 catalyst, and detected oxygen containing compound (CO 2 ) as reaction product, suggesting the participation of lattice oxygen.…”

Influence of Catalytic Formulation and Operative Conditions on Coke Deposition over CeO2-SiO2 Based Catalysts for Ethanol Reforming

“…The broad peaks originated from about 2ϴ = 15° to 35° are the reflections ascribable to amorphous silica framework [34]. In addition, the XRD data of all the samples display the presence of characteristic lines of ceria cubic phase [35] (at 2ϴ = 28.5°, 33.0°, 47.4°, and 56.3°). No other peaks were detected over the samples after active species deposition: NiO and PtOx phase are not visible and this may be due to the low metals amount (the experimental composition of the samples is reported in Table 1) or well-dispersed oxides [36].…”

Unexpected selective enhancement of the thermal stability of aromatic polyimide materials by cerium dioxide nanoparticles

“…Conversely, in other papers, a negative influence of ceria on the aforementioned property of the polymer has been reported . The latter viewpoint seems to be more reasonable, taking into account the catalytic activity of ceria in the destruction of various organic species . In this context, of special interest is the possible influence of ceria nanofiller on the thermal stability of nanocomposite materials based on thermally stable polymers, eg, aromatic polyimides (PIs)…”

“…19 The latter viewpoint seems to be more reasonable, taking into account the catalytic activity of ceria in the destruction of various organic species. 20,21 In this context, of special interest is the possible influence of ceria nanofiller on the thermal stability of nanocomposite materials based on thermally stable polymers, eg, aromatic polyimides (PIs). 22 In the present study, the thermal stability of a series of polymerceria composite materials based on PIs of different structure was investigated and compared with that of the corresponding unfilled PIs.…”