A comprehensive DFT study of CO2 catalytic conversion by H2 over Pt-doped Ni catalysts |
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| Affiliation: | 1. Key Laboratory of Low-grade Energy Utilization Technologies and Systems of Ministry of Education, School of Energy and Power Engineering, Chongqing University, Chongqing, 400044, China;2. Key Laboratory of Special Purpose Equipment and Advanced Processing Technology (Zhejiang University of Technology), Ministry of Education, Hangzhou, 310014, China;1. Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand;2. Center for Advanced Studies in Nanotechnology and Its Applications in Chemical, Food and Agricultural Industries and NANOTEC Center for Nanoscale Materials Design for Green Nanotechnology, Kasetsart University, Bangkok 10900, Thailand;3. Department of Materials Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Rayong 21210, Thailand;1. Department of Chemical Engineering, School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, PR China;2. School of Chemistry and Chemical Engineering, Yulin University, Yulin 719000, PR China;1. School of Energy and Power Engineering, North China Electric Power University, Baoding 071003, China;2. School of Mathematics and Physics, North China Electric Power University, Beijing 102206, China;1. Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing University, Chongqing 400044, China;2. Department of Chemical Engineering, Norwegian University of Science and Technology, Trondheim 7491, Norway;1. Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, College of Chemistry, Nanchang University, Nanchang, Jiangxi 330031, China;2. College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022, China;1. Shaanxi Key Laboratory of Energy Chemical Process Intensification, School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an, 710049, PR China;2. School of Chemistry and Chemical Engineering, Yulin University, Yulin, 719000, PR China |
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| Abstract: | Pt Ni bimetallic catalysts show superior performance for CO2 catalytic conversion by hydrogen, but the underlying mechanism and the key elementary steps in controlling the activity and selectivity of CO2 hydrogenation remain unclear. In present work, the complete reaction network for CO2 hydrogenation has been investigated systematically over Pt/Ni (111) surface based on periodic density functional theory, and active sites and reaction mechanism have been determined. It is found that HCOOH is mainly produced by undergoing the HCOO pathways while synthesis of CH3OH and CH4 via RWGS+CO hydrogenation is the dominant reaction pathway, and their selectivity are determined by the competitive reaction between hydrogenation and CO bond scission of H2COH species. The dissociation of COOH is regarded as the rate-determining step as it has the highest barrier (2.07 eV) in RWGS+CO hydrogenation. Moreover, it is observed that the doping of Pt on Ni surface can promote the transformation of CO2 into chemisorbed CO2δ− and reduce the barrier in H2 dissociation, which further facilitate the activation and hydrogenation of CO2. More importantly, the doped Pt atom could promote HxCO hydrogenation to HxCOH, meanwhile, suppress HxCOH dissociation into CHx. Especially, the activation barrier and reaction energy for C formation is markedly enhanced, and the ability for C hydrogenation is promoted over Pt/Ni (111) surface, which could lower the possibility of coke formation. These results provide helpful information in understanding the process of CO2 hydrogenation at atomic scale, and could benefit for the synthesis of Ni-based bimetallic catalysts. |
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| Keywords: | Carbon dioxide Hydrogenation Pt/Ni (111) surface Density functional theory |
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