One-pot preparation and characterization of bifunctional Ni-containing ZSM-5 catalysts

A convenient method for the incorporation of nickel into an aluminosilicate MFI type zeolite, which avoids the impregnation of nickel, drying and further calcinations steps, to produce a bifunctional catalyst in a cost efficient way, is presented. The one step preparation involves the addition of the nickel source in the zeolite preparation step and anchoring it during the crystallization process. After calcination to remove the organic template, the composite zeolite is ion exchanged to produce the acid form, which already has the nickel incorporated and no further steps are required. The incorporation of high contents of nickel (up to 5 wt% nominal) induced important modifications in the produced materials. As the amount of nickel increases, the textural properties are modified and lower micropore area and volume and higher mesopore and total volumes are observed. The amount of acidic sites decreased and the sites seem to be of the Brønsted kind. The nickel seems to be well dispersed or anchored in the prepared material and then high temperatures are used to reduce the oxidation state of nickel in the material; however, the catalyst with 1 wt% nickel incorporated showed good physical–chemical properties and was as active as other catalysts for the hydroconversion of toluene. The tested catalyst had a good tolerance to sulfur, indicating that part of the nickel incorporated is hindered from sulfur poisoning but is active for the dissociation of hydrogen during hydrogenation in the presence of sulfur.

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► Convenient method of nickel incorporation to produce a bifunctional Ni-zeolite catalyst.
► Incorporation of nickel in the zeolite synthesis gel produces a well dispersed hydrogenating site.
► Prepared H-Ni-ZSM-5 is sulfur tolerant and active for hydrocracking of toluene.