n-C4H10 autothermal reforming over MgO-supported base metal catalysts

We report n-C4H10 autothermal reforming over MgO-supported base metal catalysts at 723 K. 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 a domestic fuel cell system. After reductive treatment, both Ni/MgO and Co/MgO exhibited high n-C4H10 conversion and hydrogen formation activity; the stability of Ni/MgO was better than that of Co/MgO. The reaction route was investigated by measuring activity at various contact times. The results revealed that n-C4H10 autothermal reforming over Ni/MgO is a multi-step reaction composed of combustion, steam reforming, water gas shift reaction, and methanation. In contrast, Cu/MgO and Fe/MgO did not show reforming activity but cracking and combustion of n-C4H10. Ni/MgO and Co/MgO catalyzed H2 formation even after the oxidative treatment. However, the initial activity of Co/MgO after the oxidative treatment was lower than that after the reductive treatment and a decrease in H2 formation rate was again observed after 6 h in Co/MgO, similar to the measurements after the reductive treatment.