Interactions between Iron and Nickel in Fe-Ni Nanoparticles on Y Zeolite for Co-Processing of Fossil Feedstock with Lignin-Derived Isoeugenol

A set of low-cost monometallic Fe, Ni, and bimetallicFe-Nibifunctional H-Y-5.1 catalysts with different metal ratioswere synthesized by sequential incipient wetness impregnation. Thecatalysts were characterized in detail by N-2 physisorption,Fourier transform infrared spectroscopy with pyridine, inductivelycoupled plasma optical emission spectroscopy, X-ray diffraction (XRD),transmission and scanning electron microscopy (TEM-SEM), magicangle spinning nuclear magnetic resonance, X-ray photoelectron spectroscopy(XPS), Mo''ssbauer spectroscopy, magnetic measurements, temperature-programmedreduction (TPR), and X-ray absorption spectroscopy (XAS). The resultsrevealed that introduction of Fe led to a decrease of strong acidsites and an increase of medium Bronsted acid sites, while introductionof Ni increased the number of Lewis acid sites. The particle sizeof iron was approx. 5 nm, being ca. fourfold higher for nickel. XPSdemonstrated higher iron content on the catalyst surface comparedto nickel. Both Mo''ssbauer spectroscopy and magnetic measurementconfirmed the ferromagnetic behavior of all catalysts. In addition,the results from XRD, TEM, XPS, XAS, and magnetization suggested strongFe-Ni nanoparticle interactions, which were supported by modelingof TPR profiles. Catalytic results of the co-processing of fossilfeedstock with lignin-derived isoeugenol clearly showed that bothproduct distribution and activity of Fe-Ni catalysts stronglydepend on the metals' ratio and their interactions. Key propertiesaffected by the Fe-Ni metal ratio, which played a positiverole in co-processing, were a smaller medial metal nanoparticle size(<6 nm), a lower metal-acid site ratio, as well as presencein the catalyst of fcc FeNi alloy structure and fcc Ni doped withFe.

Automated summary

A set of low-cost monometallic Fe, Ni, and bimetallicFe-Ni bifunctional H-Y-5.1 catalysts with different metal ratios were synthesized and characterized. The introduction of Fe led to a decrease in strong acid sites and an increase in medium Bronsted acid sites, while the introduction of Ni increased the number of Lewis acid sites. The particle size of iron was approximately 5 nm, while it was about fourfold higher for nickel. XPS demonstrated higher iron content on the catalyst surface compared to nickel. The results also showed strong Fe-Ni nanoparticle interactions, which affected the catalytic performance.