期刊
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
卷 44, 期 2, 页码 819-834出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.ijhydene.2018.11.008
关键词
Carbon dioxide; Hydrogenation; Pt/Ni (111) surface; Density functional theory
资金
- National Natural Science Foundation of China [51606018]
- National Key R&D Program of China [2017YFB0603300]
- Chongqing Basic Science and Advanced Technology Research Program [cstc2017jcyjAX0324]
- Graduate Scientific Research and Innovation Foundation of Chongqing, China [CYB16022]
- Zhejiang Provincial Natural Science Foundation of China [LQ16E050011]
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 C-O 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 CO2 delta- and reduce the barrier in H-2 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. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据