DFT study of CO 2 catalytic conversion by H 2 over Ni 13 cluster
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Ó Indian Academy of Sciences Sadhana (0123456789().,-volV)FT3](0123456 789().,-volV)
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DFT study of CO2 catalytic conversion by H2 over Ni13 cluster QIANG KEa,*, LIMING KANGa, XIN CHENa,b,c,*
and YOU WUb
a Center
for Computational Chemistry and Molecular Simulation, College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, China b State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China c Oil and Gas Field Applied Chemistry Key Laboratory of Sichuan Province, College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, China E-mail: [email protected]; [email protected] MS received 30 July 2020; revised 15 September 2020; accepted 3 October 2020
Abstract. Understanding the mechanism and selectivity of CO2 catalytic conversion by H2 on a specific catalyst is of great significance in the context of renewable energy storage from a societal and technological point of view. In this paper, based on the density functional theory calculations, the possible reaction networks of CO2 hydrogenation on the Ni13 cluster are studied systematically. The adsorption energies of the reaction intermediates at various possible adsorption sites, the reaction energies and the activation energies of each elementary reaction are calculated. The results suggest that the adsorption properties of the CO2 and the intermediates on the Ni13 cluster are different from the specific crystal plane such as Ni(111) surface, and the intermediates are highly activated on the Ni13 surface. The most advantageous pathways for the production of HCOOH, CH3OH, and CH4 are determined, and the activation barrier of the corresponding rate-determining step is 1.63 eV, 1.55 eV, and 1.55 eV, respectively. This indicates that the Ni13 cluster has higher activity towards CO2 catalytic conversion compared with other catalysts such as Cu(111), Ni(111), and Pt/Ni(111) surface. Furthermore, the H3CO* hydrogenation or the dissociation is demonstrated to be the crucial step in determining the selectivity for CH3OH and CH4. Keywords. CO2 hydrogenation; Ni13 cluster; adsorption; reaction mechanism; DFT.
1. Introduction In recent years, with the depletion of fossil energy and the high cost of other energies, great attention has been paid to the research of new energy.1 Also, since the industrial revolution burned fossil fuels, the sharp rise in the concentration of carbon dioxide caused a series of problems, such as the global warming, rising sea levels, and ocean acidification.2–4 The use of CO2 hydrogenation to synthesize fuels and useful chemicals can not only effectively alleviate the greenhouse effect but also solve the energy problems.5–8 In particular, using CO2 hydrogenation to produce formic acid (HCOOH), methanol (CH3OH), and methane (CH4) is an effective and feasible solution.9–18 However, CO2 is a kinetically and thermodynamically stable molecule. Generally, the cleavage of the C–O bond requires a
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