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• Bimetallic core-shell Ni-Ru NPs were prepared in BMI.NTf 2 ionic liquid. • hydrophobic ionic liquid affords mainly C 2 + hydrocarbons. • Ru-Ni NPs in hydrophilic ionic liquid gives CO during CO 2 hydrogenation. • Positive catalytic synergistic effect is observed. • Metal segregation was observed experimentally during the catalysis. The direct conversion of carbon dioxide to hydrocarbons is one of the key solutions to both the reduction of the greenhouse effect and the sustainable production of fuels and lubricants. Here, it is demonstrated that simple bimetallic Ru/Ni nanoparticles (NPs) (2–3 nm, Ru-rich shell, and Ni-rich core) in a hydrophobic ionic liquid (IL) promote the direct hydrogenation of CO 2 to light hydrocarbons (HCs) under very mild reaction conditions in a simple batch reactor. The reaction of CO 2 with hydrogen (1:4, 8.5 bar) at 150 °C with the Ru/Ni NPs (3:2) in bis((trifluoromethyl)sulfonyl)amide (BMI.NTf 2) hydrophobic IL affords C 2 + hydrocarbons (79% alkanes and 16% olefins) with 5% CH 4 at 30% conversion. However, the reaction performed in the hydrophilic IL 1- n -butyl-3-methyl-1 H -imidazol-3-ium tetrafluoroborate affords mainly CO. The catalytic hydrogenation of CO 2 towards HCs proceeds by a two-step process with the initial conversion of CO 2 into CO by reverse gas shift reaction (RWGS), followed by Fischer-Tropsch Synthesis (FTS). The bimetallic NPs have higher catalytic efficiencies than their monometallic counter- parts, owing to strong synergy between the metals. The presence of Ni in the bimetallic NPs yields a more active RWGS catalyst, and the Ru increases the FTS towards heavier HCs. [ABSTRACT FROM AUTHOR]

Since the earliest reports on catalytic benzene hydrogenation, 1,3-cyclohexadiene and cyclohexene have been proposed as key intermediates. However, the former has never been obtained with remarkable selectivity. Herein, we report the first partial hydrogenation of benzene towards 1,3-cyclohexadiene under mild conditions in a catalytic biphasic system consisting of Ru@Pt nanoparticles (NPs) in ionic liquid (IL). The tandem reduction of [Ru(COD)(2-methylallyl)2] (COD=1,5-cyclooctadiene) followed by decomposition of [Pt2(dba)3] (dba=dibenzylideneacetone) in 1- n-butyl-3-methylimidazolium hexafluorophosphate (BMI ⋅PF6) IL under hydrogen affords core-shell Ru@Pt NPs of 2.9±0.2 nm. The hydrogenation of benzene (60 °C, 6 bar of H2) dissolved in n-heptane by these bimetallic NPs in BMI ⋅PF6 affords 1,3-cyclohexadiene with an unprecedented 21 % selectivity at 5 % benzene conversion. Conversely, almost no 1,3-cyclohexadiene was observed when using monometallic Pt0 or Ru0 NPs under the same reaction conditions and benzene conversions. This study reveals that the selectivity is related to synergetic effects of the bimetallic composition of the catalyst material as well as to the performance under biphasic reaction conditions. It is proposed that colloidal metal catalysts in ILs and under multiphase conditions ('dynamic asymmetric mixtures') can operate far from the thermodynamic equilibrium akin to chemically active membranes. [ABSTRACT FROM AUTHOR]