Uniform Ni species encapsulated in nanocrystalline ZSM–5 with enhanced catalytic performance for upgrading of fatty acids

Abstract

Acid hydrolysis of silicon source with ethylenediamine complexed Ni as metal precursors was used to synthesis a hierarchical ZSM–5 zeolite supporting Ni catalyst by one-pot method. After sequenced hydrothermal synthesis, calcination and reduction, highly dispersed Ni nanoparticles (NPs) encapsulated in hierarchical ZSM–5 catalyst (Ni@HZ) was obtained. The prepared catalyst was used for upgrading of fatty acids under H2 atmosphere. The Ni@HZ catalyst composed of nanocrystalline aggregates (∼100 nm), induced the generation of abundant intercrystallite mesopores, which promoted the diffusion of the reactants. Moreover, the uniformly distributed Ni NPs internal of nanocrystalline show high thermal stability, thus facilitating the adsorption and spillover of active hydrogen. High conversion rate of palmitic acid and stearic acid with deep deoxygenation were achieved by the synergism of acid and Ni species. Moreover, hierarchical pores in Ni@HZ catalyst improved the selectivity of isomeric products, which benefited the cold flow properties of the upgraded oil.