Study of Partial Oxidation of Methane by Ni/Al2O3 Catalyst: Effect of Support Oxides of Mg, Mo, Ti and Y as Promoters.

Catalysts of 10% Ni, supported on promoted alumina, were used to accomplish the partial oxidation of methane. The alumina support was doped with oxides of Mo, Mg, Ti and Y. An incipient wetness impregnation technique was used to synthesize the catalysts. The physicochemical properties of the catalysts were described by XRD, H2-TPR (temperature programmed reduction), BET, TGA, CO2-TPD (temperature-programmed desorption) and Raman. The characterization results denoted that Ni has a strong interaction with the support. The TGA investigation of spent catalysts displayed the anticoking enhancement of the promoters. The impact of the support promoters on the catalyst stability, methane conversion and H2 yield was inspected. Stability tests were done for 460 min. The H2 yields were 76 and 60% and the CH4 conversions were 67 and 92%, respectively, over Ni/Al2O3+Mg, when the reaction temperatures were 550 and 650 °C, respectively. The performance of the present work was compared to relevant findings in the literature.

Promotional effect of magnesium oxide for a stable nickel-based catalyst in dry reforming of methane.

The generation of synthesis gas (hydrogen and carbon monoxide mixture) from two global warming gases of carbon dioxide and methane via dry reforming is environmentally crucial and for the chemical industry as well. Herein, magnesium-promoted NiO supported on mesoporous zirconia, 5Ni/xMg-ZrO2 (x = 0, 3, 5, 7 wt%) were prepared by wet impregnation method and then were tested for syngas production via dry reforming of methane. The reaction temperature at 800 °C was found more catalytically active than that at 700 °C due to the endothermic feature of reaction which promotes efficient CH4 catalytic decomposition over Ni and Ni-Zr interface as confirmed by CH4-TSPR experiment. NiO-MgO solid solution interacted with ZrO2 support was found crucial and the reason for high CH4 and CO2 conversions. The highest catalyst stability of the 5Ni/3Mg-ZrO2 catalyst was explained by the ability of CO2 to partially oxidize the carbon deposit over the surface of the catalyst. A mole ratio of hydrogen to carbon monoxide near unity (H2/CO ~ 1) was obtained over 5Ni/ZrO2 and 5Ni/5Mg-ZrO2, implying the important role of basic sites. Our approach opens doors for designing cheap and stable dry reforming catalysts from two potent greenhouse gases which could be of great interest for many industrial applications, including syngas production and other value-added chemicals.