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DFT Study of Catalytic CO₂ Hydrogenation over Pt-Decorated Carbon Nanocones: H₂ Dissociation Combined with the Spillover Mechanism

Yodsin, Nuttapon, Rungnim, Chompoonut, Tungkamani, Sabaithip, Promarak, Vinich, Namuangruk, Supawadee, Jungsuttiwong, Siriporn
Journal of physical chemistry 2019 v.124 no.3 pp. 1941-1949
carbon, carbon dioxide, catalysts, catalytic activity, density functional theory, desorption, dissociation, energy, equations, formates, formic acid, hydrogen, hydrogenation, platinum
In this work, we investigate the catalytic role of platinum-decorated defective CNC (Pt/dCNC) in CO₂ hydrogenation to formic acid (FA) by a density functional theory (DFT) approach. The reaction follows the equation CO₂₍g₎ + H₂₍g₎ → HCOOH₍g₎. Combining highly reactive Pt atoms with defective CNC provides Pt/dCNC, a reactive monodispersed atomic catalyst for CO₂ hydrogenation. We propose our new mechanism of CO₂ hydrogenation over the Pt/dCNC catalyst involving a H₂ dissociation and H spillover sequence that is energetically favorable. The rate-determining step is formic acid desorption that requires an energy barrier of 1.11 eV. Furthermore, our findings show that the rate of FA production is dependent on H₂ concentration. Altogether, the theoretical results support the concept of the spillover mechanism, playing a key role in promoting CO₂ hydrogenation via a formate intermediate. These results improve our understanding of the mechanism involving H₂ dissociation with the H spillover process and the catalytic reactions that are very important for the development of highly efficient catalysts for CO₂ conversion into FA.