New synthetic route for the production of mayenite support to enhance Ni resistance to coke deposition in the reforming of tar model compounds

Four nickel/mayenite catalysts were synthesized. Mayenite was prepared from different precursors, namely boehmite (AlO(OH)) + Ca(NO3)2·4H2O and gibbsite + Ca(OH)2, for each couple a specific procedure was followed. The effect of the Ni addition method was also evaluated, comparing wet impregnation and direct inclusion of nickel precursor during mayenite preparation. The obtained catalysts were characterized by XRD, BET, SEM/EDS and TPR. The Ni/mayenite catalysts were tested in steam reforming of toluene and pyrocatechol, chosen as tar model compounds. The experiments were conducted in a fixed-bed lab-scale atmospheric reactor, evaluating carbon conversion, hydrogen selectivity and stability. Characterization of the spent catalysts after toluene steam reforming experiments by XRD and DTG-TPO were performed to assess structural changes and carbon deposition. Kinetic parameters of toluene steam reforming were determined for the different catalysts.