Glycerol steam reforming for hydrogen production: design of Ni supported catalysts

In this work the activity of Ni catalysts in hydrogen production by glycerol steam reforming was studied. Moreover the effect of the support (TiO2, SBA-15 and ZrO2) on the catalytic performance of Ni was evaluated. A strong effect of the support on the activity of the samples was detected. The Ni/TiO2 sample showed negligible activity mainly due to the low strength of anatase to keep nickel in the reduced state. In fact, both incorporation of Ni ions into the nanoanatase lattice and oxidation of the active phase to NiO under operating conditions were observed. A deactivation process was also found with the Ni/SBA-15 sample while the best results were achieved with the Ni/ZrO2 catalyst, showing no deactivation. After 20 hours, the glycerol conversion was ca. 72% and the H2 yield was ca. 65%. The Ni/ZrO2 sample was even more active when tested at lower temperatures, although its performance was less stable. On the basis of the experimental results, it was evidenced that the nature of the support affects above all the stability of the active phase. In particular, strong interactions between the metal active phase and the support ensures stability, activity and selectivity of the catalyst in glycerol steam reforming reactions.