A study on the adsorptions of SO2 on pristine and phosphorus-doped silicon carbide nanotubes as potential gas sensors
| Autor: | Song-tao Xiao, Guang-hui Chen, Wang-qiang Lin, Ling-yu Wang, Qiang Wang, Fang Li |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Silicon business.industry Process Chemistry and Technology chemistry.chemical_element Carbon nanotube Surfaces Coatings and Films Electronic Optical and Magnetic Materials law.invention Semiconductor Adsorption Chemical engineering Physisorption chemistry law Chemisorption Desorption Materials Chemistry Ceramics and Composites Density functional theory business |
| Zdroj: | Ceramics International. 46:25171-25188 |
| ISSN: | 0272-8842 |
| DOI: | 10.1016/j.ceramint.2020.06.307 |
| Popis: | In this work, the adsorptions of one of important gas pollutant, i.e., SO2 on pristine silicon carbon nanotube (SiCNT) and phosphorus-doped SiCNT (P-SiCNT) are investigated theoretically, including the adsorption configurations, energetics, electronic structures, the sensitivity and the recovery time of desorption based on density functional theory (DFT). To dope the SiCNT, a carbon or silicon atom was replaced with a phosphorus atom to build PC-SiCNT and PSi-SiCNT. It is found that SO2 can be chemisorbed on the surfaces of SiCNT, PC-SiCNT and PSi-SiCNT with monodentate and cycloaddition configurations. For the encapsulations, SO2 can be formed chemisorption inside PC-SiCNT, and physisorption inside SiCNT and PSi-SiCNT. For the adsorption of SO2 on the surface or inside of PC-SiCNT, the configurations of M1–SO2–PC-SiCNT and SO2–PC-SiCNT are converted from metal for PC-SiCNT to semiconductor. For the adsorptions of SO2 on the surfaces of PSi-SiCNT, M1–SO2–PSi-SiCNT, M2–SO2–PSi-SiCNT and C1–SO2–PSi-SiCNT are converted from metal for PSi-SiCNT to semiconductors with the significant decrease of conductivity, while after encapsulation of SO2 inside PSi-SiCNT, SO2–PSi-SiCNT still maintains metallicity. In addition, PC-SiCNT and PSi-SiCNT have superior sensing performance to SO2 compared with SiCNT. And SO2 can be desorbed from SiCNT, PC-SiCNT and PSi-SiCNT under 673 K with the recovery time of 9.63, 33.6 and 16.4 s, respectively. Furthermore, the selectivity and of SO2 based on GCMC in the mixtures of SO2–CO2, SO2–N2 and SO2–CO2–N2 on PC-SiCNT and PSi-SiCNT are much larger and better than that on SiCNT. Based on MD simulation, we found that SO2 has the ideal diffusion ability on SiCNT and PSi-SiCNT. In summary, PSi-SiCNT may have potential application as SO2 gas sensor. |
| Databáze: | OpenAIRE |
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