A first principles study of carbon monoxide hydrogenation on cobalt (۰۰۱)surface.

Carbon monoxide (CO) is a colorless, odorless, and non-irritable gas [۱]. Fischer–Tropschsynthesis (FTS) is a process that has been used for many decades as it gives access to industriallyimportant chemicals from CO [۲]. As the products of FTS are a complex mixture of a wide rangeof organic compounds, selectivity toward desired products is the most important issue in thisreaction. In recent years, there has been an increasing motivation to deploy FTS at commercialscales, which has fueled the search for high-performance catalysts [۳]. Several catalysts have beenexamined for their potential to catalyze CO hydrogenation. Transition metal catalysis has longbeen recognized as a reliable and modular means of constructing complex molecules from simple,readily accessible starting materials[۴]. Periodic plane-wave density functional theory (DFT)calculations were carried out to study the CO adsorption and its reactivity with adsorbed hydrogenon the Co (۰۰۱) surface. All parts of this study employed the Vienna Ab initio Simulation Package(VASP) [۵]. The results show that CH۴, CH۳OH, and C۲H۲ are the products, according to thecalculations CH۴ is the main product. We found that the preferred mechanism for COhydrogenation is through HCO and cis-HCOH, and the largest exothermic reaction energy in theCH۴ formation pathway is released during the hydrogenation of cis-HCOH (−۰.۷۷۳ eV). Aninvestigation of the kinetics demonstrates that the CH production from cis-HCOH has the lowestenergy barrier. On the other hand, the hydrogenation of CO to COH is the least favored reactionkinetically.

Keywords:

Carbon monoxide , Fischer–Tropsch Synthesis , Cobalt catalyst , DFT