Insight into the effects of electronegativity on the H catalytic activation for CO hydrogenation: four transition metal cases from a DFT study

• Published in: Catalysis science & technology 2020-08, Vol.1 (16), p.5641-5647
• Main Authors: Chen, Haipeng, Yang, Minjian, Liu, Jinqiang, Lu, Guojian, Feng, Xun
• Format: Article
• Language: English
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/d0cy01009j

The choice of CO 2 hydrogenation for improving product selectivity is closely related to the type of active H species on the catalyst surface. Herein, we report a density functional theory (DFT) study on H 2 activation and CO 2 pre-hydrogenation over four transition metal surfaces, i.e. , Fe(111), Ni(111), Ru(0001) and Pt(111), to reveal the effect of metal electronegativity on the path choice of CO 2 hydrogenation. Metal electronegativity dominates the type of active H species on transition metal surfaces. Negative H − (1s 2 ) from H 2 dissociation on Fe(111) prefers to combine with the C-site of CO 2 benefiting for the C-terminal hydrogenation, and positive H + (1s 0 ) from H 2 dissociation on Pt(111) prefers to combine with the O-site of CO 2 benefiting for the O-terminal hydrogenation. The selective hydrogenation on Ni(111) and Ru(0001) are affected by CO 2 activation due to their close electronegativity to that of H. This study reveals the effect of electronegativity on the selective hydrogenation of CO 2 , which is helpful to design new catalysts for the hydrogenation of CO 2 to value-added chemicals. Electronegativity of transition metal dominates the type of H species, which has an important effect on the path choice of CO 2 hydrogenation.