C–O bond activation and splitting behaviours of CO2 on a 4H-SiC surface: a DFT study

Dandan Wang; Liangliang Zhang; Dongxue Han; Li Niu; Xin Zhong; Xin Qu; Lihua Yang; Jialong Zhao; Haibo Li

doi:10.1039/C8CP04438D

C–O bond activation and splitting behaviours of CO₂ on a 4H-SiC surface: a DFT study†

Dandan Wang,^a Liangliang Zhang,

*^b Dongxue Han,^cd Li Niu,^cd Xin Zhong,

^a Xin Qu,

^a Lihua Yang,^a Jialong Zhao

^a and Haibo Li*^a

Author affiliations

* Corresponding authors

^a Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Siping 136000, China
E-mail: lihaibo@jlnu.edu.cn

^b State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Eastern South Lake Road, Changchun 130033, China
E-mail: Zhangliangliang@ciomp.ac.cn

^c Center for Advanced Analytical Science, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China

^d State Key Laboratory of Electroanalytical Chemistry, c/o Engineering Laboratory for Modern Analytical Techniques, Changchun Institute of Applied Chemistry, Chinese Academy of Science, Changchun, China

Abstract

Conversion of CO₂ into valuable chemicals can not only reduce the amount of CO₂ in the atmosphere, but also realize the reuse of resources. It's well known that C–O bond activation and splitting are critical steps in the CO₂ conversion process and it's crucial to employ an appropriate catalyst. Here, the adsorption and activation behaviors of a CO₂ molecule on 4H-SiC surfaces were systematically investigated based on DFT calculations. Calculation results show that the CO₂ molecule can anchor on 4H-SiC(0001) and (000 [1 with combining macron] ) surfaces. On the 4H-SiC(0001) surface, the adsorbed CO₂ molecule prefers to dissociate with an energy barrier of 0.52–0.70 eV, producing an O adatom and a CO molecule on the surface. Further dissociation of the CO is hindered due to a large energy barrier of 2.12 eV. However, if a H atom is introduced, the CO molecule may combine with H into a CHO group and the reaction energy barrier is 1.69 eV. Moreover, the CHO group tends to transform into a CH group and an O adatom, a reaction in which a relatively low energy barrier of 0.09 eV needs to be surmounted. For the 4H-SiC(000 [1 with combining macron] ) case, the direct C–O bond dissociation energy barrier for CO₂ is only 0.37 eV while further breaking of the C–O bond in CO is energetically unfavorable even with the help of a H atom. So the final products are an O adatom and CO chemisorbed on the 4H-SiC(000) surface. All the calculation results demonstrate that the inert CO₂ molecule can be effectively activated on both the 4H-SiC(0001) and (000 [1 with combining macron] ) surfaces and different splitting products could be obtained on the two different surfaces, implying that SiC is an applicable catalyst material for CO₂ conversion with high efficiency and product selectivity.

This article is part of the themed collection: 2018 PCCP HOT Articles

Physical Chemistry Chemical Physics

C–O bond activation and splitting behaviours of CO₂ on a 4H-SiC surface: a DFT study†

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C–O bond activation and splitting behaviours of CO₂ on a 4H-SiC surface: a DFT study

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