M.G. González

Effect of addition of CaO on Ni/Al2O3 catalysts over CO2 reforming of methane

The Ni/γ–Al2O3 catalyst was modified by CaO in order to improve the thermal stability and the carbon deposition resistance during the CO2 reforming of methane to syngas reaction. The catalytic performance, thermal stability, structure, dispersivity of nickel and carbon deposition of the modified and unmodified catalysts were investigated by a series of characterization techniques (X-ray diffraction (XRD), BET, H2 chemisorption, temperature programmed reduction (TPR) and flow-reaction). Results showed that catalysts modified with CaO improve their stability better than the nickel-based catalysts.

Preparation of supported Cu/ZSM-5 zeolite films for DeNOx reaction

Abstract This work reports the in situ synthesis of ZSM-5 zeolite films on cordierite and the performance of a Cu/ZSM-5-coated monolithic catalyst in the lean NO x reduction reaction. At the end of the hydrothermal crystallization, a zeolite/cordierite composite was obtained which consists of a continuous zeolite film that strongly attaches to the sustrate surface. The monolithic catalysts so prepared are active for the reduction of NO.

Ni/γ-Al2O3 catalyst from kaolinite for the dry reforming of methane

Abstract A catalyst consisting of a 5% Ni over a γ-Al 2 O 3 novel support was evaluated under high-temperature reaction conditions. The γ-Al 2 O 3 -rich phase was obtained by selective dissolution of siliceous components of heat-treated kaolinite. The support was appropriate to prepare a catalyst with high surface area (170 m 2 /g) that showed to be active and stable for dry reforming of methane at 650 °C and a CH 4 /CO 2 =0.5 molar ratio. Compared to the conventional Ni/α-Al 2 O 3 catalyst, this new material showed an improved sulfur resistance when it was reduced in hydrogen steam at the reaction temperature. In industrial conditions, CH 4 /CO 2 =1, deactivation by carbon deposition was not increased. The content and type of deposited carbon were analyzed by TPH and TPO techniques. As regeneration methods of the coked catalysts, hydrogen and oxygen carbon treatments were employed. After the treatment with hydrogen the catalyst reaches the initial activity, but with oxygen the activity only is partially regenerated.

CO2 reforming of CH4 over Mo promoted nickel-based catalysts

Abstract It has been studied the effects of Mo addition on the stability, the sulfur poisoning and carbon deposition over Ni based catalysts for CO 2 reforming of methane. The Ni catalysts promoted with small amount of Mo increases the stability of the catalyst and decreases the carbon deposition. In order to characterize the carbon deposited on the catalysts during CO 2 reforming reaction, TEM and TPO experiments were carried out after reaction. Formation of filamentous carbon was determined. In the presence of H 2 S containing feeds (0.1 ppm), Ni thioresistance also increases with Mo content.

Preparation and Characterization of Supported Vanadia Catalyst for the Selective Catalytic Reduction of NO with NH3

The structure characteristics and the catalytic behavior are analyzed on catalysts obtained by oxidative degradation of a planar VO complex on alumosilicate support (cordierite). By means of different techniques (FTIR, DRX, TGA), vanadium oxide formation was determined during the thermal decomposition of the organometallic precursor and the formation of NH4 species during the reaction. Besides, the catalytic activity was also determined for the selective reduction of NO with ammonia.

Double perovskites La2MMnO6 as catalyst for propane combustion

Abstract The synthesis, structural, spectroscopic and morphological characterization; as well as the evaluation of the catalytic properties, of a family of oxides La2MMnO6, with M = Co, Ni and Cu are presented in this work. The materials were obtained by solid state reaction and through citrate route. The structure was determined by X-ray diffraction and a correlation was found between the crystal cell parameters and the M(II) cation sizes, as a consequence of MO6 and MnO6 octahedral ordering. According to infrared spectroscospic characterization of the materials prepared by citrate route, a diminution of the M4+-O bond strength was observed, according with M(II) sizes, in the sequence: Cu > Ni > Co. More labile O species should be present in La2CoMnO6-CIT. The electron microscopy morphology of this oxide confirmed the presence of agglomerated tiny particles. The presence of nanometic crystallites was confirmed by transmission electron microscopy. The catalytic tests, using propane as reaction test, were carried out in a fixed bed micro reactor, coupled with an “on line” chromatograph. The materials obtained by citrate route, despite M(II) cations, are better suited for propane combustion and the catalyst La2CoMnO6 is the most active of the investigated series with T90 ∼ 500 °C.