Revealing the mechanism of oxygen vacancy defect for CO2 adsorption and diffusion on CaO: DFT and experimental study
The calcium looping is a promising technology to achieve industrial CO2 capture, and the introduction of oxygen vacancy can promote the CO2 capture reactivity of CaO-based sorbents. In this work, DFT calculations were performed to investigate the CO2 adsorption by CaO in the presence of oxygen vacan...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2024-01-01
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| Series: | Journal of CO2 Utilization |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2212982023002597 |
| _version_ | 1827382448341647360 |
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| author | Xianyao Yan Chenyu Duan Shuihua Yu Bing Dai Chaoying Sun Huaqiang Chu |
| author_facet | Xianyao Yan Chenyu Duan Shuihua Yu Bing Dai Chaoying Sun Huaqiang Chu |
| author_sort | Xianyao Yan |
| collection | DOAJ |
| description | The calcium looping is a promising technology to achieve industrial CO2 capture, and the introduction of oxygen vacancy can promote the CO2 capture reactivity of CaO-based sorbents. In this work, DFT calculations were performed to investigate the CO2 adsorption by CaO in the presence of oxygen vacancy defect. The presence of oxygen vacancy reduces the band gap of CaO surface, which results from the delocalization of Ca 2p orbital. Besides, the electron accumulation at the oxygen vacancy occurs due to the unsaturated Ca-O bonds, and the reaction possibility is promoted neighbouring the defect. The top site of oxygen vacancy defect of CaO is favourable for CO2 adsorption. The adsorption energy of CO2 on CaO with oxygen vacancy achieves − 2.52 eV, which is 1.81 times as high as that on pristine CaO. Due to strong interaction between CO2 and CaO with oxygen vacancy, CO2 migration from this site is more difficult, while the following diffusion is more prone to occur. In the presence of steam, CO2 adsorption energy is enhanced to − 2.70 eV on CaO with oxygen vacancy, and the distance from CO2 radical to surface is intuitively reduced, which results from the electrons donated from defect and neighbouring Ca atoms, while CO2 diffusion difficulty is increased. This work provides an incisive investigation for structural, electronic, and thermodynamic characteristics of CO2 adsorption and diffusion on CaO in the presence of oxygen vacancy defect, and it can shed light on rational synthesis and functional design of surface-active sites of CaO-based sorbents. |
| first_indexed | 2024-03-08T14:20:45Z |
| format | Article |
| id | doaj.art-089a9ad514e04769b17f4d978c9a6dc6 |
| institution | Directory Open Access Journal |
| issn | 2212-9839 |
| language | English |
| last_indexed | 2024-03-08T14:20:45Z |
| publishDate | 2024-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of CO2 Utilization |
| spelling | doaj.art-089a9ad514e04769b17f4d978c9a6dc62024-01-14T05:38:27ZengElsevierJournal of CO2 Utilization2212-98392024-01-0179102648Revealing the mechanism of oxygen vacancy defect for CO2 adsorption and diffusion on CaO: DFT and experimental studyXianyao Yan0Chenyu Duan1Shuihua Yu2Bing Dai3Chaoying Sun4Huaqiang Chu5Key Laboratory of Metallurgical Emission Reduction & Resources Recycling (Anhui University of Technology), Ministry of Education, Maanshan 243002, PR China; School of Energy and Environment, Anhui University of Technology, Maanshan 243002, PR ChinaSchool of Energy and Environment, Anhui University of Technology, Maanshan 243002, PR ChinaSchool of Energy and Environment, Anhui University of Technology, Maanshan 243002, PR ChinaKey Laboratory of Metallurgical Emission Reduction & Resources Recycling (Anhui University of Technology), Ministry of Education, Maanshan 243002, PR China; Corresponding authors.School of Energy and Environment, Anhui University of Technology, Maanshan 243002, PR China; Corresponding authors.School of Energy and Environment, Anhui University of Technology, Maanshan 243002, PR China; Corresponding authors.The calcium looping is a promising technology to achieve industrial CO2 capture, and the introduction of oxygen vacancy can promote the CO2 capture reactivity of CaO-based sorbents. In this work, DFT calculations were performed to investigate the CO2 adsorption by CaO in the presence of oxygen vacancy defect. The presence of oxygen vacancy reduces the band gap of CaO surface, which results from the delocalization of Ca 2p orbital. Besides, the electron accumulation at the oxygen vacancy occurs due to the unsaturated Ca-O bonds, and the reaction possibility is promoted neighbouring the defect. The top site of oxygen vacancy defect of CaO is favourable for CO2 adsorption. The adsorption energy of CO2 on CaO with oxygen vacancy achieves − 2.52 eV, which is 1.81 times as high as that on pristine CaO. Due to strong interaction between CO2 and CaO with oxygen vacancy, CO2 migration from this site is more difficult, while the following diffusion is more prone to occur. In the presence of steam, CO2 adsorption energy is enhanced to − 2.70 eV on CaO with oxygen vacancy, and the distance from CO2 radical to surface is intuitively reduced, which results from the electrons donated from defect and neighbouring Ca atoms, while CO2 diffusion difficulty is increased. This work provides an incisive investigation for structural, electronic, and thermodynamic characteristics of CO2 adsorption and diffusion on CaO in the presence of oxygen vacancy defect, and it can shed light on rational synthesis and functional design of surface-active sites of CaO-based sorbents.http://www.sciencedirect.com/science/article/pii/S2212982023002597CO2 captureCaODensity functional theoryDiffusionOxygen vacancy |
| spellingShingle | Xianyao Yan Chenyu Duan Shuihua Yu Bing Dai Chaoying Sun Huaqiang Chu Revealing the mechanism of oxygen vacancy defect for CO2 adsorption and diffusion on CaO: DFT and experimental study Journal of CO2 Utilization CO2 capture CaO Density functional theory Diffusion Oxygen vacancy |
| title | Revealing the mechanism of oxygen vacancy defect for CO2 adsorption and diffusion on CaO: DFT and experimental study |
| title_full | Revealing the mechanism of oxygen vacancy defect for CO2 adsorption and diffusion on CaO: DFT and experimental study |
| title_fullStr | Revealing the mechanism of oxygen vacancy defect for CO2 adsorption and diffusion on CaO: DFT and experimental study |
| title_full_unstemmed | Revealing the mechanism of oxygen vacancy defect for CO2 adsorption and diffusion on CaO: DFT and experimental study |
| title_short | Revealing the mechanism of oxygen vacancy defect for CO2 adsorption and diffusion on CaO: DFT and experimental study |
| title_sort | revealing the mechanism of oxygen vacancy defect for co2 adsorption and diffusion on cao dft and experimental study |
| topic | CO2 capture CaO Density functional theory Diffusion Oxygen vacancy |
| url | http://www.sciencedirect.com/science/article/pii/S2212982023002597 |
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