Carbon dioxide reforming of methane over ordered mesoporous NiO–Al2O3 composite oxides

Ordered mesoporous NiO–Al2O3 composite oxides with different nickel content were facilely synthesized via an improved evaporation induced self-assembly (EISA) strategy with Pluronic P123 as template in absolute ethanol solvent. The catalytic properties of the obtained mesoporous materials were investigated for the carbon dioxide reforming of methane reaction. These materials were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption and desorption characterization, H2 temperature-programmed reduction (TPR), and thermogravimetry (TG). It was observed that these catalysts with mesostructure presented both high catalytic activity and long stability. The improved catalytic performance was suggested to be closely associated with both the amount of ‘‘accessible’’ active centers for the reactants on the mesopore wall surface and the stabilisation of the active sites by the alumina matrix due to the ‘‘confinement effect’’ of the mesopores. The ‘‘confinement effect’’ existing among the mesoporous structure of the materials contributed to preventing Ni particles from sintering under severe reduction and reaction conditions. The stabilized Ni nanoparticles had strong resistance to carbon deposition, accounting for no deactivation after a 100 h long-term stability test at 700 1C. Thus, the ordered mesoporous NiO–Al2O3 composite oxides promised a novel and stable series of catalyst candidates for the carbon dioxide reforming of methane reaction.