The search for catalysts with features that can improve coke resistance and decrease byproduct formation is a current goal in H₂ production from renewable sources. In this work, the effect of the presence of Ni nanoparticles over Co/La-Ce oxides on the ethanol decomposition reaction was studied. Catalysts were synthetized using as precursor a La_0.8Ce_0.2Ni_xCo_1-xO₃ perovskite-type material to ensure a low segregation of phases and a high dispersion of metals. After reduction at 873 K, the perovskite structure was destroyed, and metal Co-Ni particles were supported over a lanthanum-cerium oxide. The materials were characterized by different techniques before and after reaction. Solids exhibited metal particle sizes between 5 and 15 nm demonstrating the advantages of the preparation method to obtain Ni-Co alloys. Although the results of adsorption of ethanol followed by diffuse reflectance infrared fourier transformed spectroscopy (DRIFTS) showed acetate species strongly adsorbed on the catalyst’s surface, the material (Ni_0.7Co_0.3/La_0.8Ce_0.2) with the lowest particle size was the most stable system leading to the lowest amount of carbon deposits during ethanol decomposition. This catalyst showed the better performance, with a higher ethanol conversion (98.4%) and hydrogen selectivity (75%). All catalysts exhibited carbonaceous deposits, which were an ordered and disordered carbon phase mixture.

Catalytic pyrolysis has been used to upgrading the quality of pyrolytic liquids. Herein, we report a comprehensive study on the catalytic pyrolysis of waste tires using Ni/SiO₂ as catalysts. The analyses were carried out by combining thermogravimetry (TGA), TGA interfaced to a Fourier Transform Infrared spectrometer (TGA–FTIR), and pyrolysis coupled to gas chromatography/mass spectrometer (Py–GC/MS) techniques. During waste tire decomposition, the main functional groups detected in the FTIR were alkenes, aromatics, and heteroatoms-containing groups such as nitrogen, sulfur, and oxygen. Meanwhile, by Py-GC/MS were identified mainly D,L-limonene, isoprene, benzene, toluene, xylenes (BTX), and p-cymene. The Py–GC/MS experiments at three different temperatures (350, 400, and 450 °C) suggested an effect of the catalyst on product distribution. The Ni catalyst promoted cyclization reactions and subsequently aromatization, leading to an improved vapors composition. The use of iso-conversional kinetic models along with master plots allows proposing a multiple-step reaction mechanism, which was well described by the Avrami-Erofeev, Random Scission, and truncated Sestak–Berggren models. The values of activation energies show differences for the catalyzed and uncatalyzed pyrolysis (111.0 kJ mol^-1 and 168.4 kJ mol^-1), validating the effectivity of Ni/SiO₂. Finally, the thermal Biot (>1) and Py^I and Py^II numbers (10^-3<Py^I <10^-1 and 10^-2< Py^II<10^-3) confirms that the process is being occurred between the kinetic and the convection-limited regimes.