Search

• 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]

Rh 0.5 Pd 0.5 /CeO 2 bimetallic nanoparticles were subjected to reducing and oxidizing atmospheres at different temperatures and characterized by means of the Ambient Pressure X-Ray Photoelectron Spectroscopy (AP-XPS). The surface atomic population is calculated for all cases. By using a high temperature pre-treatment at 480 °C in H 2 atmosphere, it was possible to control the surface atomic population with Pd atoms frozen at the skin layer even in an oxidizing atmosphere, which is not observed without high temperature pre-treatment (Rh atoms at the skin layer). The change of the Rh/Pd surface segregation behavior after the high temperature pre-treatment is attributed to the geometrical factor of Strong Metal Support Interaction (SMSI) effect, i.e., the occurrence of the ceria capping layer around nanoparticles. [ABSTRACT FROM AUTHOR]