Comparative Study on the Hydrogenation of Naphthalene over Both Al(2)O(3)-Supported Pd and NiMo Catalysts against a Novel LDH-Derived Ni-MMO-Supported Mo Catalyst

[Image: see text] Naphthalene hydrogenation was studied over a novel Ni–Al-layered double hydroxide-derived Mo-doped mixed metal oxide (Mo-MMO), contrasted against bifunctional NiMo/Al(2)O(3), and Pd-doped Al(2)O(3) 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 (k(1)) and decalin (k(2)). The Mo-MMO catalyst achieved comparable reaction rates to Pd(2%)/Al(2)O(3) at double concentration. When using Pd(5%)/Al(2)O(3), tetralin hydrogenation was favored over naphthalene hydrogenation culminating in a k(2) value of 0.224 compared to a k(1) value of 0.069. 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/Al(2)O(3). Consequently, Mo-MMO presents an opportunity to generate more alkyl naphthenes in subsequent hydrodecyclization 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 Al(2)O(3)-supported Pd catalysts, as a result of octalin intermediate orientations on the catalyst surface as a function of the electronic properties of Pd catalysts.