Binary Ni–Cu heterogeneous catalysts are known to demonstrate excellent activity in conventional hydrogenation of phenolic compounds, and Cu addition facilitates hydrodeoxygenation (HDO). In this study, we aimed to show the effect of Cu on the specific catalytic activity and selectivity of Ni–Cu catalysts in transfer hydrogenation, in which 2-PrOH was used as a solvent and an H donor. Catalytic transformations of anisole were studied in sub- and supercritical alcohol at 150 and 250 °C. The catalysts were prepared using an environmentally friendly supercritical antisolvent coprecipitation method, which makes it possible to obtain well-dispersed particles (less than 7 nm) at high metal loading (up to 50 wt.%). When copper is added, deactivation of the catalyst in transformations of anisole, including HDO, is observed. The experimental data and the appropriate kinetic analysis demonstrate that there is a decrease in the rate of anisole conversion accompanied by an increase in the concentration of acetone formed during the dehydrogenation of 2-PrOH.

The influence of the reaction medium on the surface structure and properties of a Ni-based catalyst used for the reductive transformations of O-, N-, and S-containing aromatic substrates under hydrogen transfer conditions has been studied. The catalysts were characterized by XRD, XPS, and IR spectroscopy and TEM methods before and after the reductive reaction. It has been shown that the conversion of 1-benzothiophene causes irreversible poisoning of the catalyst surface with the formation of the Ni₂S₃ phase, whereas the conversion of naphthalene, 1-benzofuran, and indole does not cause any phase change of the catalyst at 250 °C. However, after the indole conversion, the catalyst surface remains enriched with N-containing compounds, which are evenly distributed over the surface.

Mixed Ni-Al oxide catalytic precursors with different elemental ratios (20, 50, and 80 wt.% Ni⁰) were synthesized using green supercritical antisolvent co-precipitation (SAS). The obtained oxide precursors and metal catalysts were characterized in detail by X-ray diffraction (XRD) analysis, atomic pair distribution function (PDF) analysis, CO adsorption, and high-resolution transmission electron microscopy (HRTEM). It was found that the composition and structure of the Ni-Al precursors are related to the Ni content. The mixed Ni_1−xAl_xO oxide with NiO-based crystal structure was formed in the Ni-enriched sample, whereas the highly dispersed NiAl₂O₄ spinel was observed in the Al-enriched sample. The obtained metal catalysts were tested in the process of anisole H₂-free hydrogenation. 2-PrOH was used as a hydrogen donor. The catalyst with 50 wt.% Ni⁰ demonstrated the highest activity in the hydrogenation process.