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

Abstract

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.