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.
Highlights
CO2 capture and utilization (CCU) is the process of capturing CO2 anthropogenic emissions and using them to synthesize valuable and useful chemicals
If CO2 obtained from the atmosphere or from local emitters is the starting molecule for the synthesis, the FT reaction can be combined with the reverse water gas-shift reaction (RWGS, Equation (3))
The aim of this paper is the analysis of the structure, composition and stability of unsupported Fe-Co alloy NPs, synthesized via Inert Gas Condensation (IGC), and their catalytic properties in the CO2 hydrogenation reaction
Summary
CO2 capture and utilization (CCU) is the process of capturing CO2 anthropogenic emissions and using them to synthesize valuable and useful chemicals. The production of liquid synthetic fuels is especially interesting for large scale energy storage because they retain all the benefits of liquid fossil fuels, such as high energy density and stability in ambient conditions [1,2] In this framework, the quest for a material that efficiently catalyzes the reaction between CO2 and H2 is of key importance, since CO2 is a very stable molecule (∆fH0298 K,CO2 = −393.5 kJ/mol). If CO2 obtained from the atmosphere or from local emitters is the starting molecule for the synthesis, the FT reaction can be combined with the (endothermic) reverse water gas-shift reaction (RWGS, Equation (3)) Another variation is the direct conversion of CO2 to higher hydrocarbons via a FT-like reaction (Equation (4))
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
