Engineering of Ruthenium–Iron Oxide Colloidal Heterostructures: Improved Yields in CO 2 Hydrogenation to Hydrocarbons

Identifying Performance Descriptors in CO2 Hydrogenation over Iron-Based Catalysts Promoted with Alkali Metals

Alkali metal promoters have been widely employed for preparation of heterogeneous catalysts used in many industrially important reactions. However, the fundamentals of their effects are usually difficult to access. Herein, we unravel mechanistic and kinetic aspects of the role of alkali metals in CO₂ hydrogenation over Fe-based catalysts through state-of-the-art characterization techniques, spatially resolved steady-state and transient kinetic analyses. The promoters affect electronic properties of iron in iron carbides. These carbide characteristics determine catalyst ability to activate H₂ , CO and CO₂ . The Allen scale electronegativity of alkali metal promoter was successfully correlated with the rates of CO₂ hydrogenation to higher hydrocarbons and CH₄ as well as with the rate constants of individual steps of CO or CO₂ activation. The derived knowledge can be valuable for designing and preparing catalysts applied in other reactions where such promoters are also used.

Ligand-mediated formation of Cu/metal oxide hybrid nanocrystals with tunable number of interfaces

Combining domains of different chemical nature within the same hybrid material through the formation of heterojunctions provides the opportunity to exploit the properties of each individual component within the same nano-object; furthermore, new synergistic properties will often arise as a result of unique interface interactions. However, synthetic strategies enabling precise control over the final architecture of multicomponent objects still remain scarce for certain classes of materials. Herein, we report on the formation of Cu/MO x (M = Ce, Zn and Zr) hybrid nanocrystals with a tunable number of interfaces between the two domains. We demonstrate that the organic ligands employed during the synthesis play a key role in regulating the final configuration. Finally, we show that the synthesized nanocrystals serve as materials platforms to investigate the impact of the Cu/metal oxide interfaces in applications by focusing on the electrochemical CO2 reduction reaction as one representative example.