Support Effects on the Activity of Ni Catalysts for the Propane Steam Reforming Reaction

The catalytic performance of supported Ni catalysts for the propane steam reforming reaction was investigated with respect to the nature of the support. It was found that Ni is much more active when supported on ZrO₂ or YSZ compared to TiO₂, whereas Al₂O_3- and CeO₂-supported catalysts exhibit intermediate performance. The turnover frequency (TOF) of C₃H₈ conversion increases by more than one order of magnitude in the order Ni/TiO₂ < Ni/CeO₂ < Ni/Al₂O₃ < Ni/YSZ < Ni/ZrO₂, accompanied by a parallel increase of the selectivity toward the intermediate methane produced. In situ FTIR experiments indicate that CH_x species produced via the dissociative adsorption of propane are the key reaction intermediates, with their hydrogenation to CH₄ and/or conversion to formates and, eventually, to CO, being favored over the most active Ni/ZrO₂ catalyst. Long term stability test showed that Ni/ZrO₂ exhibits excellent stability for more than 30 h on stream and thus, it can be considered as a suitable catalyst for the production of H₂ via propane steam reforming.