Ce - promoted catalyst from hydrotalcites for CO2 reforming of methane: calcination temperature effect

Abstract

Recebido em 25/7/11; aceito em 11/2/12; publicado na web em 15/6/12Ce-promoted Ni-catalysts from hydrotalcites were obtained. The effect of calcination temperature on the chemical and physical properties of the catalysts was studied. Several techniques were used to determine the chemical and physical characteristics of oxides. The apparent activation energies of reduction were determined. Catalytic experiments at 48 L g -1 h -1 without pre-reduction in CO 2 reforming of methane were performed. The spinel-like phase in these oxides was only formed at 1000 °C. The reduction of Ni 2+ in the oxides was clearly affected by the calcination temperature which was correlated with catalytic performance. The catalyst calcined at 700 °C showed the greatest activity.

Role of Pr on Ni–Mg–Al Mixed Oxides Synthesized by Microwave-Assisted Self-Combustion for Dry Reforming of Methane

“…NiO species in the mixed oxides have a strong interaction with the structure, as they are part of the solid solution . The reduction peaks are asymmetric in shape in all the profiles toward low temperatures, which may be due to the reduction of nonstoichiometric Ni oxide to Ni 2+ . Wang et al pointed out the importance of the strength of the Ni-support interaction on the performance of the catalysts for DRM, since it improves the activity and decreases the formation of carbon.…”

“…Our research group has studied the synthesis of CeO 2 -promoted Ni–Mg–Al catalysts by coprecipitation and self-combustion obtaining very interesting results in terms of catalytic stability and demonstrating beneficial effects of the Ce. ,− Inspired by these catalytic systems and based on the properties that Pr can have as redox promoter, in the present work we propose, for the first time, the synthesis by microwave-assisted self-combustion of mixed Ni–Mg–Al oxides containing PrO 2 (Pr 6 O 11 ) as catalyst precursors for DRM. The objective of this investigation was to study the promoter role that Pr (in variable nominal concentrations) has on the physicochemical properties of Ni–Mg–Al oxides, emphasizing the basicity and the particle size of the active site and its relationship with the catalytic performance of solids.…”

CO2 Adsorption on Modified Mg–Al-Layered Double Hydroxides

“…This effect is only observed when LDHs are treated to certain temperatures, beyond which the thermal decomposition becomes irreversible due to the formation of stable phases such as spinel and MIIM2IIIO4 MIIO. In the case of hydrotalcites, the spinel phase is formed close to 1000 °C (Velu et al 1999;Daza et al 2012). These temperatures depend on the MII and MIII metals and the anions present in the LDH structure (Bellotto et al 1996).…”