Details of CO2 electrochemical reduction reaction (CO2ERR) on Mn–MoS2 monolayer: a DFT study

• Published in: Theoretical chemistry accounts 2023-07, Vol.142 (7), Article 60
• Main Authors: Afugu, Amos, Kwawu, Caroline R., Menkah, Elliot, Tia, Richard, Adei, Evans
• Format: Article
• Language: English
• Subjects: Atomic properties; Atomic/Molecular Structure and Spectra; Carbon dioxide; Carbon sequestration; Chemical reduction; Chemistry; Chemistry and Materials Science; Cobalt; Density functional theory; Electronegativity; Electrons; Formic acid; Inorganic Chemistry; Iron; Manganese; Methanol; Molybdenum disulfide; Monolayers; Nickel; Organic Chemistry; Physical Chemistry; Reducing agents; Single atom catalysts; Theoretical and Computational Chemistry
• ISSN: 1432-881X; 1432-2234
• DOI: 10.1007/s00214-023-03001-z

Understanding the detailed mechanism of CO 2 electrochemical reduction (CO 2 ERR) on catalytic surfaces, leading to the formation of carbon one (C 1 ) products, serves as a plausible means for CO 2 mitigation. The adsorption of single-atom catalysts (SACs) on MoS 2 monolayer surface for CO 2 electrochemical reduction reaction (CO 2 ERR) was studied using density functional theory (DFT) method. Among the selected SACs (Mn, Fe, Co, Ni), manganese (Mn) activated CO 2 to the highest extent, with O–C–O bond angle of 142.84 ° . From our results, single atoms with large size and low atomic number (low d -orbital electrons) will have weak binding to the MoS 2 as seen for Mn. Large atoms with lower electronegativity act as better reductants, reducing both the surface and the CO 2 molecule adsorbed. Since CO 2 activation is a very critical reaction step, we anticipate better performance of Mn-doped MoS 2 to its counterparts, i.e. Fe, Ni and Co. In a 2-electron/2-proton reduction process, CO formation will occur at 0 V; however, formic acid will occur at a higher onset potential of − 1.03 V. Methanol will prefer to occur via the CO pathway at − 0.88 V. Selectively CO 2 reduction is favoured in the order: CO > methanol > formic acid. The rate-limiting step for methanol production is observed to be the CH 2 OH formation step (∆ G  = 0.88 eV). Although the pristine MoS 2 monolayer is inactive for catalysing CO 2 ERR offering CO 2 physisorption, the introduction of adatoms serves as a site for CO 2 sequestration, activation and electrochemical reduction.