Steam reforming of surrogate diesel model over hydrotalcite-derived MO-CaO-Al2O3 (M = Ni & Co) catalysts for SOFC applications

Abstract

Catalytic steam reforming of diesel fuel has the potential for producing syngas or hydrogen that can be feed to a fuel cell (especially SOFC) for portable power generation. Cost-effective, highly active reforming catalysts with resistance towards carbon formation and sulfur poisoning are critically needed to commercialize such technologies successfully. Thus in the present work, we have explored CaO-Al2O3 based hydrotalcite structure derived catalyst precursors for syngas production via steam reforming of a diesel model compound (n-dodecane). The steam reforming of n-dodecane reactions was also carried out in the presence of 100 ppm of sulfur compounds at a steam-to-carbon ratio of 2. Among all the catalysts tested, the Co-CaO-Al2O3 catalyst gave the best catalytic performance with respect to n-dodecane conversion, stability, and carbon suppression. At 700 °C, the Co-CaO-Al2O3 catalyst possesses > 90% of n-dodecane conversions with a negligible carbon formation (1.04 mg C/g.h) for a period of 24 h. It is also observed that upon deactivation due to sulfur poisoning, the Co-CaO-Al2O3 catalyst can be regenerated by a simple thermal treatment at 750 °C, which is due to the considerably low decomposition temperature behavior of CoSx and CaS species formed for this catalyst. Lower carbon deposition over the Co-CaO-Al2O3 catalyst can be attributed to the better oxygen affinity of Co species and higher normalized basicity than other catalysts.