Mono- and bimetallic Ni-, Ru- and Pt-modified hierarchical ZSM-5 materials were prepared by impregnation technique and characterized by X-ray diffraction (XRD), N₂ physisorption, temperature-programmed reduction (TPR–TGA), ATR–FTIR and solid state NMR spectroscopy. Formation of finely dispersed nickel, ruthenium and platinum species was observed on the bimetallic catalysts. It was found that the peculiarity of the used zeolite structure and the modification procedure determine the type of formed metal oxides and their dispersion and reducibility. The samples’ acidity was studied via FTIR spectroscopy of adsorbed pyridine. The changes in the zeolite structure were studied via solid-state NMR spectroscopy. The catalysts were investigated in a gas-phase hydrodeoxygenation, transalkylation and dealkylation reaction of model lignin derivative molecules for phenol production.

Mono- and bimetallic Ni- and Ru-modified micro-mesoporous ZSM-5 catalysts were prepared by wet impregnation. The influence of the Ni content, the addition of Ru and the sequence of the modification by two metals on the physicochemical properties of the catalysts were studied. They were characterized by X-ray powder diffraction (XRD), N₂ physisorption, temperature-programmed reduction (TPR-TGA), TEM and XPS spectroscopy. Formation of finely dispersed nickel and/or ruthenium oxide species was observed on the external surface and in the pores of zeolite support. It was found that the peculiarity of the used zeolite structure and the modification procedure determine the type of formed metal oxides, their dispersion and reducibility. XPS study revealed that the surface became rich in nickel and poorer in ruthenium for bimetallic catalysts. Ni had higher dispersion in the presence of ruthenium, and TPR investigations also confirmed its facilitated reducibility. The studied catalysts were tested in CO₂ hydrogenation to methane. 10Ni5RuZSM-5 material showed the highest activity and high selectivity for methane formation, reaching the equilibrium conversion and 100% selectivity at 400 °C. Stability and reusability of the latter catalyst show that it is appropriate for practical application.

Mono-, and bimetallic Ni-, Ru-, and Pt-modified nanosized Beta zeolite catalysts were prepared by the post synthesis method and characterized by powder X-ray diffraction (XRD), nitrogen physisorption, HRTEM microscopy, temperature-programmed reduction (TPR-TGA), ATR FT-IR spectroscopy, and by solid-state MAS-NMR spectroscopy. The presence of nanosized nickel-oxide, ruthenium-oxide, and platinum species was detected on the catalysts. The presence of Brønsted and Lewis acid sites, and incorporation of nickel ions into zeolite lattice was proven by FT-IR of adsorbed pyridine. The structural changes in the catalyst matrix were investigated by solid state NMR spectroscopy. The catalysts were used in a gas-phase hydrodemethoxylation and dealkylation of 2-methoxy-4-propylphenol as a lignin derivative molecule for phenol synthesis.

Monometallic (Cu, Ni) and bimetallic (Cu-Ni) catalysts supported on KIT-6 based mesoporous silica/zeolite composites were prepared using the wet impregnation method. The catalysts were characterized using X-ray powder diffraction, N₂ physisorption, SEM, solid state NMR and H₂-TPR methods. Finely dispersed NiO and CuO were detected after the decomposition of impregnating salt on the silica carrier. The formation of small fractions of ionic Ni²⁺ and/or Cu²⁺ species, interacting strongly with the silica supports, was found. The catalysts were studied in the gas-phase upgrading of lignocellulosic biomass-derived levulinic acid (LA) to γ-valerolactone (GVL). The bimetallic, CuNi-KIT-6 catalyst showed 100% LA conversion at 250 °C and atmospheric pressure. The high LA conversion and GVL yield can be attributed to the high specific surface area and finely dispersed Cu-Ni species in the catalyst. Furthermore, the catalyst also exhibited high stability after 24 h of reaction time with a GVL yield above 80% without any significant change in metal dispersion.

Monometallic Co- and Ni- and bimetallic Co–Ni-containing catalysts supported on nanosized β-zeolite were prepared by a post-synthesis impregnation method and evaluated for the catalytic upgrading of biomass-derived levulinic acid (LA) to γ-valerolactone (GVL), an important platform molecule for the production of renewable fuels and value-added chemicals. The catalysts were characterized by XRD, N₂ physisorption, H₂-TPR, DR UV–Vis, solid-state NMR, XPS, FTIR of adsorbed pyridine and H₂ chemisorption. Increasing metal loading resulted in the formation of larger NiO and Co₃O₄ domains, while metal incorporation modified the zeolite framework and reduced its Brønsted acidity. Among the studied catalysts, the bimetallic 15 wt.%Co–15 wt.%Ni/β-zeolite exhibited the highest catalytic activity, achieving complete LA conversion and 92% GVL yield at 150 °C and retaining 98% conversion after three reaction cycles. The enhanced catalytic behavior of bimetallic catalysts is attributed to the synergistic interaction between cobalt and nickel species, leading to the formation of highly dispersed metallic Ni/Co and probably Ni-Co alloy nanoparticles with improved reducibility and hydrogenation activity. In addition, the combination of metallic hydrogenation sites and acidic centers provided by the β-zeolite support promotes the consecutive hydrogenation required for efficient GVL formation. The results demonstrate that Co–Ni-modified β-zeolite is a promising low-cost alternative to noble-metal catalysts for the valorization of biomass-derived levulinic acid and highlight the importance of metal–metal and metal–support interactions in the design of efficient bifunctional catalysts for sustainable biomass conversion.