Comparative study on the hydrogenation of naphthalene over both Al2O3‑supported Pd and NiMo catalysts against a novel LDH-derived Ni-MMO-supported Mo catalyst

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Authors

Colleges, School and Institutes

Abstract

Naphthalene hydrogenation was studied over a novel Ni-Al layered double hydroxide-derived Mo-doped mixed metal oxide (Mo-MMO), contrasted against bifunctional NiMo/Al2O3, and Pd-doped Al2O3 catalysts, the latter of which with Pd loadings of 1, 2 and 5 wt%. Reaction rate constants were derived from a pseudo-first order kinetic pathway describing a two-step hydrogenation pathway to tetralin (k1) and decalin (k2). The Mo-MMO catalyst achieved comparable reaction rates to Pd2%/Al2O3 at double concentration. When using Pd5%/Al2O3, tetralin hydrogenation was favoured over naphthalene hydrogenation culminating in a k2 value of 0.224 compared to a k1 value of 0.069. The Ni and Mo-based catalysts produced the most significant cis-decalin production, with Mo-MMO culminating at a cis/trans ratio of 0.62 as well as providing enhanced activity in naphthalene hydrogenation compared to NiMo/Al2O3. Consequently, Mo-MMO presents an opportunity to generate more alkyl naphthenes in subsequent hydrodecyclisation reactions and therefore a higher cetane number in transport fuels. This is contrasted by a preferential production of trans-decalin observed when using all of the Al2O3-supported Pd catalysts, as a result of the octalin intermediate orientations on the catalyst surface as a function of the electronic properties of Pd catalysts.

Details

Original languageEnglish
Pages (from-to)1-15
Number of pages15
JournalACS Omega
Volume2021
Publication statusPublished - 19 Jul 2021