The effects of Fe, Mg, and Pt-doping on the improvement of Ni stabilized on Al2O3-CeO3 catalysts for methane dry reforming

Herein, the promotional effects of Mg, Fe, and Pt on Ni-based catalysts supported on Al2O3-CeO2 (Ni/Al2O3-CeO2) were investigated in the dry reforming of methane (DRM) reaction. The interaction of a suitable amount of MgO and FeO with Ce2O3 stabilized in the catalysts was demonstrated by the temperature-programmed desorption of CO2 (CO2-TPD). Ce2O3 has a high basicity for adsorbing CO2, generating a monoclinic Ce2O2CO3 species in the DRM reaction. Surface oxygen ions were also produced by adding MgO and FeO, as demonstrated by the temperature-programmed reduction of H2 (H2-TPR). Monoclinic Ce2O2CO3 and surface oxygen may both be used to oxidize and remove the carbon that was deposited, maintaining the high activity and stability of the metal Ni and Pt catalysts. The high dispersion and synergistic interactions between the platinum and oxide phases, which are associated with the decrease in reduction temperature and the rise in the number of basic sites, are responsible for the increased activity of Pt with M-Ni/Al2O3-CeO2 catalysts. The co-doped Ni/Al2O3-CeO2 catalysts with Mg and Fe significantly enhanced the activity (more than 80% methane and 84% CO2 conversion), the selectivity toward syngas (∼90%), and maintained the H2/CO ratio at about 0.97 at 700 °C.

γ-Valerolactone Production from Levulinic Acid Hydrogenation Using Ni Supported Nanoparticles: Influence of Tungsten Loading and pH of Synthesis

γ-Valerolactone (GVL) has been considered an alternative as biofuel in the production of carbon-based chemicals; however, the use of noble metals and corrosive solvents has been a problem. In this work, Ni supported nanocatalysts were prepared to produce γ-Valerolactone from levulinic acid using methanol as solvent at a temperature of 170 °C utilizing 4 MPa of H₂. Supports were modified at pH 3 using acetic acid (CH₃COOH) and pH 9 using ammonium hydroxide (NH₄OH) with different tungsten (W) loadings (1%, 3%, and 5%) by the Sol-gel method. Ni was deposited by the suspension impregnation method. The catalysts were characterized by various techniques including XRD, N₂ physisorption, UV-Vis, SEM, TEM, XPS, H₂-TPR, and Pyridine FTIR. Based on the study of acidity and activity relation, Ni dispersion due to the Lewis acid sites contributed by W at pH 9, producing nanoparticles smaller than 10 nm of Ni, and could be responsible for the high esterification activity of levulinic acid (LA) to Methyl levulinate being more selective to catalytic hydrogenation. Products and by-products were analyzed by ¹H NMR. Optimum catalytic activity was obtained with 5% W at pH 9, with 80% yield after 24 h of reaction. The higher catalytic activity was attributed to the particle size and the amount of Lewis acid sites generated by modifying the pH of synthesis and the amount of W in the support due to the spillover effect.

Reforming of methane with carbon dioxide over cerium oxide promoted nickel nanoparticles deposited on 4-channel hollow fibers by atomic layer deposition

CeO₂ can significantly enhance the catalytic performance of Ni/Al₂O₃ catalysts prepared by atomic layer deposition for dry reforming of methane.

Facile one-step preparation of ordered mesoporous Ni–M–Al (M = K, Mg, Y, and Ce) oxide catalysts for methane dry reforming

Excellent DRM performances of a Ni–Y–Al oxide catalyst is related to the comprehensively advantageous textural properties, such as high Ni dispersion, large surface area, and small Ni nanoparticles inlaid in the honeycomb-like mesoporous skeleton.