Carbon dioxide reduction on an intercalated graphene substrate
||Carbon dioxide reduction on an intercalated graphene substrate|
||SNIC Medium Compute|
||Karin Larsson <firstname.lastname@example.org>|
||2019-10-01 – 2020-10-01|
||10403 10407 10404|
The climate change issues have, during the past decade, become an active topic for both scientific and political debate. The decrease in CO2 emission is a great challenge for the twentyfirst century. The atmospheric CO2 level also needs to be reduced. It can be done only by capturing and converting them into useful fuels with the help of catalysts.
We intend to study the detailed mechanism for catalytic conversion of CO2 into chemical feedstocks over a modified graphene surface. In this project, there is a focus on the formation of various intercalated 2D metals (i.e., within a SiC/graphene interface). This project is a continuation of an earlier project. As a first step towards the development of an efficient catalyst, we have already (in the earlier project) explored the effect by Rh intercalation within graphene/SiC surfaces. So far, the adsorption energies, bonding configurations, bond lengths, and vibrational frequencies for all surface intermediates involved in the reaction mechanisms, have been studied. Our preliminary results for a methanol synthesis suggest that the hydrogenation of CO2 to CO occurs via the reverse-water-gas shift (RWGS) reaction, rather than via formate, or direct C-O bond cleavage, pathways. Our next step within this continuation project will be to calculate the reaction barrier energies for each of the elementary steps that are involved in the hydrogenation of CO2. The purpose is then to elucidate the minimum energy pathway. We also intend to perform kinetic Monte-Carlo simulations with the purpose to explore how the energetics will affect the kinetics of the reactions. We will use this technique in order to determine the overall rates for CO2 conversion and production of CO, CH3OH, and CH4, respectively, under reaction conditions. The effect by other intercalated metals, such as Ge, Ag and Au, on the reduction of CO2, will also be studied. This also include intercalation with H.
Within the earlier project, we have also performed calculations for hydrogen production through photocatalytic water splitting over BeN2 2D surfaces. Our results suggest that this material is structurally, thermally, and dynamically stable. From band alignment with respect to the water redox potentials, our results indicate that the photo-generated holes at the valence band can oxidize water to oxygen, and that the photo-generated electrons at the conduction band can reduce water to hydrogen (without the aid of any co-catalyst). Our next goal in the continuation project is to determine the stability of the BeN2 monolayer in an aqueous environment by performing ab inito molecular dynamics simulations.