Computational screening of novel catalysts for oxidation and nitrogen reduction reactions
||Computational screening of novel catalysts for oxidation and nitrogen reduction reactions|
||Jonas Björk <email@example.com>|
||2021-08-06 – 2022-09-01|
The proposed project aims at exploring new catalysts for performing dehydrogenation reactions. The main goal is finding candidates able to replace expensive noble-metal based catalysts currently in place for turning short alkanes into alkenes, of high value as building blocks in chemical industry. In addition to previous years we will also focus on the Haber-Bosch cycle for production of ammonia from nitrogen and hydrogen gas.
Dehydrogenation reactions occur in virtually all areas of chemical science. For example, in the possibly simplest reaction, saturated alkanes are turned into unsaturated alkenes by removing two hydrogen atoms and transforming a carbon-carbon single bond into a double-bond. The importance of alkenes is reflected by the fact that ethylene (the smallest alkenes) has the highest production of all organic compounds, with a continuously growing demand . Despite their obvious importance, state-of-the-art production of alkenes is based on expensive Pt based catalysts. Therefore, finding an alternative, cheaper way of catalysing alkene production would have a potential global impact.
Recently, it was shown (both from experiment and theory) that the surface of transition-metal carbides (commonly referred to as MXenes) are able to catalyse the conversion of ethylbenzene into styrene , which is a reaction in which ethyl functional groups are dehydrogenated into ethenyl, reminiscent of the ethane-to-ethene reaction. The reaction is enabled due to the oxidative environment of the MXene surface, which is covered by oxygen atoms, efficiently reducing the activation energy of dehydrogenation. Importantly, this is the only study, before we initiated this project, making use of MXenes for dehydrogenation reactions.
Inspired by this study, we intend to investigate how MXenes, and other types of low-dimensional surfaces with oxidative capacities, may be used to catalyse different types of dehydrogenation reactions. Our prime target is finding potential catalysts for alkane dehydrogenation given the great potential impact of such work.
During the first years of this project we already found a simple descriptor that can be used to quickly evaluate how well different MXenes perform for dehydrogenation reactions. We plan to increase the complexity of our description to more realistic scenarios. In addition, we will investigate the potential of ammonia synthesis by making use of single-atom catalysts supported on MXenes.
The project will make us of density functional theory calculations coupled with transition state theory methods for finding transition states and estimating reaction rates. The methods will be used in order to find catalysts with high chemical selectivity towards desired reaction products (such as alkenes).
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