Engineering of Ruthenium–Iron Oxide Colloidal Heterostructures: Improved Yields in CO₂ Hydrogenation to Hydrocarbons

Abstract

Catalytic CO2 reduction to fuels and chemicals is a major pursuit in reducing greenhouse gas emissions. One approach utilizes the reverse water‐gas shift reaction, followed by Fischer–Tropsch synthesis, and iron is a well‐known candidate for this process. Some attempts have been made to modify and improve its reactivity, but resulted in limited success. Now, using ruthenium–iron oxide colloidal heterodimers, close contact between the two phases promotes the reduction of iron oxide via a proximal hydrogen spillover effect, leading to the formation of ruthenium–iron core–shell structures active for the reaction at significantly lower temperatures than in bare iron catalysts. Furthermore, by engineering the iron oxide shell thickness, a fourfold increase in hydrocarbon yield is achieved compared to the heterodimers. This work shows how rational design of colloidal heterostructures can result in materials with significantly improved catalytic performance in CO2 conversion processes.

Advances in the Design of Heterogeneous Catalysts and Thermocatalytic Processes for CO2 Utilization

“…Recently, bimetallic catalysts with Fe as active metal were studied to promote CO2 conversion. [227][228][229][230][231] Especially, addition of Co was found to increase the carbide formation, which was beneficial for the chain propagation reaction. It was also observed that the product selectivity could be tuned by changing the Fe/Co ratio.…”

In situ tuning of electronic structure of catalysts using controllable hydrogen spillover for enhanced selectivity

“…For instance, a well-defined model system demonstrated that on the nonreducible alumina support, hydrogen spillover is limited to short distances, with the hydrogen flux decreasing over distance to create a concentration gradient 25 . In-depth understanding of hydrogen spillover can not only help to explain experimental phenomena but also aid the design of advanced catalysts with enhanced catalytic performances [27][28][29][30][31][32][33][34][35] . Being inspired by these researches, we posit that there is an opportunity for an approach to modulating the electronic structure of active sites through regulating hydrogen spillover strength for enhanced catalytic performance.…”

Designing Nanoparticles and Nanoalloys for Gas-Phase Catalysis with Controlled Surface Reactivity Using Colloidal Synthesis and Atomic Layer Deposition

“…For the purpose of investigating the promoting effect of Ru on Fe with respect to the selective hydrogenation of CO 2 to hydrocarbons, Aitbekova et al [ 141 ] synthesized well-defined Al 2 O 3 -supported “Ru/FeO x heterodimers” ( Figure 8 a) via the successive growth of iron oxide NPs (~13.1 nm) on pre-synthesized Ru NPs (~4.8 nm). Through in situ XAS studies, the authors proposed that the synergistic effect between Ru and Fe is implemented via hydrogen spillover from Ru to neighboring Fe.…”