Influence of support on catalytic behavior of nickel catalysts in oxidative steam prereforming of n-butane for fuel cell applications

Oxidative steam reforming of n-butane over supported Ni catalysts at relatively low temperature, 723 K, is reported. Catalytic performance was investigated not only after H2 treatment at 1073 K “reductive treatment” but also after subsequent O2/Ar treatment at the reaction temperature “oxidative treatment” to mimic the shutdown and startup of the domestic fuel cell system. After the reductive treatment, n-butane conversion attained 100% for all the catalyst at a lower space velocity (SV) of 67 L(h g)−1. Differences in catalytic activity were emphasized at a higher SV of 667 L(h g)−1, and were attributed to corresponding differences in metal surface area. Since a fraction of Ni in some catalysts was oxidized during the reaction at the higher SV, the reaction at the higher SV was indicated to be kinetically more oxidative condition. Although Ni/Al2O3 was inactive at the lower SV after the oxidative treatment, n-butane conversion of the other catalysts attained 100%. In contrast, only Ni/MgO was able to convert n-butane at the higher SV after the oxidative treatment. Therefore it was revealed that nickel oxide species on the catalyst were reduced by n-butane in the reactant even under severe oxidative conditions.

Figure optionsDownload as PowerPoint slide