CO2 Hydrogenation over Unsupported Fe-Co Nanoalloy Catalysts

Abstract

The thermo-catalytic synthesis of hydrocarbons from CO2 and H2 is of great interest for the conversion of CO2 into valuable chemicals and fuels. In this work, we aim to contribute to the fundamental understanding of the effect of alloying on the reaction yield and selectivity to a specific product. For this purpose, Fe-Co alloy nanoparticles (nanoalloys) with 30, 50 and 76 wt% Co content are synthesized via the Inert Gas Condensation method. The nanoalloys show a uniform composition and a size distribution between 10 and 25 nm, determined by means of X-ray diffraction and electron microscopy. The catalytic activity for CO2 hydrogenation is investigated in a plug flow reactor coupled with a mass spectrometer, carrying out the reaction as a function of temperature (393–823 K) at ambient pressure. The Fe-Co nanoalloys prove to be more active and more selective to CO than elemental Fe and Co nanoparticles prepared by the same method. Furthermore, the Fe-Co nanoalloys catalyze the formation of C2-C5 hydrocarbon products, while Co and Fe nanoparticles yield only CH4 and CO, respectively. We explain this synergistic effect by the simultaneous variation in CO2 binding energy and decomposition barrier as the Fe/Co ratio in the nanoalloy changes. With increasing Fe content, increased activation temperatures for the formation of CH4 (from 440 K to 560 K) and C2-C5 hydrocarbons (from 460 K to 560 K) are observed.

Asymmetric Oxo‐Bridged ZnPb Bimetallic Electrocatalysis Boosting CO2‐to‐HCOOH Reduction

“…Zn(Pb) electrodes were prepared by a one‐step co‐electrodeposition strategy by which a series of Zn(Pb) films with controllable lead concentrations can be produced (Table S1 , Supporting Information). X‐ray diffraction (XRD) measurements confirmed the Zn(Pb) structure to include metallic Zn, although the (002), (100), and (101) peaks are shifted toward higher angles and split with increasing Pb content, [ 31 ] as shown in Figure 1 a . This trend refers to the compression and tension [ 32 ] of Zn phases due to the embedded Pb atoms supported by the XRD simulation presenting a similar pattern, as shown in Figure S1 in the Supporting Information.…”

Ab Initio Study of the C–O Bond Dissociation in CO2 Reduction by Redox and Carboxyl Routes on 3d Transition Metal Systems

“…Calizzi et al. reported that, on unary Fe and Co nanoparticles, the major products were CO and CH 4 , respectively . However, on FeCo nanoalloys with different metal ratios, they observed the formation of C 2 to C 5 hydrocarbons and suggested that the synthesis proceeds by RWGS–FT reactions.…”

Evolution of Structural and Magnetic Properties of Fe-Co Wire-like Nanochains Caused by Annealing Atmosphere

“…This observation is related to their partial oxidation during thermal treatment. Finally, it is worth adding that the obtained results can be considered as an important source of information for the application of thermally-treated Fe-Co nanochains as magnetic and microwave absorbers [ 27 , 28 ] or in catalysis [ 29 , 30 ].…”

“…The obtained results are collected and comprehensively described in this work. Moreover, it is worth noting that they can be considered as an important source of information for the application of the thermally-treated iron-cobalt Wire-like nanochains in the magnetic and microwave absorbers [ 27 , 28 ] or catalysis [ 29 , 30 ].…”