Examinando por Autor "Morales, Anabel"

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Hydrogen Production through Oxidative Steam Reforming of Acetic Acid over Ni Catalysts Supported on Ceria-Based Materials
(MDPI, 2022-11-27) Megía, Pedro J.; Morales, Anabel; Vizcaíno, Arturo J.; Calles, José A.; Carrero, Alicia
Oxidative steam reforming allows higher energy efficiency and lowers coke deposition compared to traditional steam reforming. In this work, CeO2-based supports have been prepared with Ni as the active phase, and they were tested in the oxidative steam reforming of acetic acid. The influence of the O2/AcOH molar ratio (0–0.3) has been evaluated over Ni/CeO2. The results stated that by increasing oxygen content in the feeding mixture, acetic acid conversion increases too, with a decrease in coke deposition and hydrogen yield. To have a proper balance between the acetic acid conversion and the hydrogen yield, an O2/AcOH molar ratio of 0.075 was selected to study the catalytic performance of Ni catalysts over different supports: commercial CeO2, a novel mesostructured CeO2, and CeO2-SBA-15. Due to higher Ni dispersion over the support, the mesostructured catalysts allowed higher acetic acid conversion and hydrogen yield compared to the nonporous Ni/CeO2. The best catalytic performance and the lowest coke formation (120.6 mgcoke·gcat -1·h-1) were obtained with the mesostructured Ni/CeO2. This sample reached almost complete conversion (>97%) at 500 ºC, maintaining the hydrogen yield over 51.5% after 5 h TOS, being close to the predicted value by the thermodynamic equilibrium that is due to the synergistic coordination between Ni and CeO2 particles.
Oxidative steam reforming of acetic acid on Ni catalysts: Influence of the La promotion on mesostructured supports
(Elsevier, 2023) Megía, Pedro J.; Morales, Anabel; Vizcaíno, Arturo J.; Calles, José A.; Carrero, Alicia
In this work, the support effect and the La2O3 promotion of Ni-based catalysts on the oxidative steam reforming of acetic acid as bio-oil model compound has been studied. Ni/ SBA-15 showed the worst catalytic performance with an acetic acid conversion dropping below 30% at 500 C ascribed to active phase oxidation. In contrast, Ni supported over mesoporous CeO2 (CeO2-m) reached better catalytic performance and lower coke formation due to the higher Ni dispersion and oxygen mobility of the support. On the other hand, La2O3 promotion to SBA-15 and CeO2-m led to even higher Ni dispersion and prevented sintering during the reforming reaction. This effect resulted in an improvement in the catalytic performance for both promoted samples. As a consequence of low Ni crystallite size and high oxygen mobility, Ni/La2O3eCeO2-m reached almost complete conversion (~96%), the highest hydrogen yield (~53%) maintained for 5 h with the lowest coke formation...