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Cu catalysts supported on CeO2, TiO2 and CeO2/TiO2 were prepared by precipitation method and used for preferential oxidation of carbon monoxide contained in a hydrogen flow generated by methane steam reforming. The samples were characterized by XRD, BET and TPR techniques. The catalytic properties were studied in the 50-330ºC range by using a quartz micro-reactor vertically positioned on an electrical furnace. The results showed that the small copper particles generated with the lower metal content are the most easily reducible and give the best catalytic performance. In respect of support effect, the strong metal-support interaction and the redox characteristics of the CuOx-CeO2 series resulted in the best catalytic results, especially with the sample with 1% copper content.

LaNiO3 perovskite was modified by partial substitution of nickel by cobalt in order to increase the stability and resistance to carbon deposition during the methane CO2 reforming. The results showed that a suitable combination of precipitation and calcination steps resulted in oxides with the desired structure and with important properties for application in heterogeneous catalysis. The partial substitution of Ni by Co resulted in lower rates of conversion of both the reactants, but the catalyst stability was highly increased. The LaNi0.3Co0.7O3 catalyst, calcined at 800 ºC, was the most active under the reaction conditions.

Mo-promoted Ni/Al2O3 catalysts for the methane steam reforming reaction were studied in this work. The Ni/Al2O3 catalysts were prepared by precipitation and molibdenum was added by impregnation up to 2%wt. The solids were tested using a micro-reactor under two H2Ov/C conditions and were characterized by ICP-OES, XRD, N2 adsoption, H2 chemisorption and TPR. NiO and NiAl2O4 phases were observed and the metallic area decreased with the increase of the Mo content. From the catalytic tests high stability was verified for H2Ov/C=4.0. On the other hand, only the catalyst containing 0,05% Mo stayed stable during 30 hours of the test at H2Ov/C=2.0.

Mixed metal oxides with perovskite-type structure show a great potential to be used in catalysis, electrocatalysis and electronic ceramics. Perovskites oxides catalysts with the composition LaNiO3, LaNi(1-x)Fe xO3 and LaNi(1-x)Co xO3 (x = 0.4 and 0.7) have been synthesized by the precipitation method to be used in the methane reforming to produce hydrogen and synthesis gas. The compounds were characterized by X-ray diffraction, thermogravimetric and differential thermal analysis, inductively coupled plasma atomic emission spectroscopy, surface area measurements, energy dispersive X-ray spectrometry coupled to scanning electron microscopy and temperature programmed reduction. The results showed that a suitable combination of the preparation method with calcination variables (time and temperature) could result in oxides with the desired structure and with important properties at the application point of view in heterogeneous catalysis.