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利用光学气敏材料吸附气体，引起材料光学性质的变化来测量气体成分，是当前气敏传感研究领域的一个热点方向. 本文针对光学气敏材料金红石相TiO2（110）表面吸附CO分子的微观特性进行研究，采用基于密度泛函理论（DFT）体系下的第一性原理平面波超软赝势方法，计算了表面的吸附能、电子态密度、光学性质和电荷密度的变化. 结果表明：终止于二配位O原子的TiO2（110）面为最稳定表面，该表面吸附CO分子以C端吸附方式最为稳定，且氧空位浓度越高，越有助于对CO分子的吸附，吸附过程为放热. 在氧空位浓度为33%时，吸附能达到1.319 eV，吸附后结构趋于更加稳定. 表面吸附CO分子后，其实质是表面的氧空位氧化了CO分子，CO分子的电荷向材料表面转移. 含有氧空位的表面吸附CO分子后都改善了其在可见光范围内的光学性质，但是氧空位浓度越高，改善其光吸收和反射能力越明显，光学气敏传感特性表现越显著.Using the optical gas sensing materials to adsorb gases can cause the changes of the optical properties of materials. This method can be used to measure the gas composition and is a hot topic of current research in the field of gas sensitive sensors. This paper studies the micro-characteristics of rutile TiO2 (110) surface adsorption of CO molecules. By using the first-principles plane-wave ultrasoft pseudopotential method based on the density functional theory (DFT), the adsorption energy, electron density of states, optical properties and charge density of the surface are calculated. Results show that the TiO2 (110) surface terminating in two coordinated O atoms is the most stable surface, and the structure with C-terminal of CO molecules adsorbed on the surface is the most stable. The higher the oxygen vacancy concentration, the more helpful it is to the adsorption of surface CO molecules. This process is exothermic. When the oxygen vacancy concentration is 33%, the adsorption energy can reach 1.319 eV. After adsorption, the structure of the surface tends to be more stable. Oxygen vacancy oxidizing the CO molecule is the essence of the adsorption process, and the charge of a CO molecule is transferred to the material surface. The CO molecules adsorbed on TiO2 (110) surface containing oxygen vacancies can improve its optical properties in visible light range; moreover, the higher the concentration of oxygen vacancy, the more obvious the improvement of absorption, reflection ability and optical gas sensing performance.
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Keywords:
- gas sensing material /
- rutile /
- CO /
- density functional theory
[1] Zhang X C, Zhao L J, Fan C M, Liang Z H, Han P D 2012 Acta Phys. Sin. 61 077101 (in Chinese) [张小超, 赵丽军, 樊彩梅, 梁镇海, 韩培德 2012 61 077101]
[2] Fujishima A, Honda K 1972 Nature 238 37
[3] Khan S U M, Al-Shahry M, Ingler Jr W B 2002 Science 297 2243
[4] Zhao J, Yang X D 2003 Building and Environment 38 645
[5] Yu X Y, Liang W, Cheng J J 2000 Bulletin of the Chinese Ceramic Society 1 53 (in Chinese)[于向阳, 梁文, 程继健 2000 硅酸盐通报 1 53]
[6] Chen X B, Liu L, Yu P Y, Peter Y Yu, Samuel S Mao 2011 Science 331 746
[7] Wang Y, Feng Q, Wang W H, Yue Y X 2012 Acta Phys. Sin. 61 193102 (in Chinese) [王寅, 冯庆, 王渭华, 岳远霞 2012 61 193102]
[8] O'Regan B, Grätzel M 1991 Nature 353 737
[9] Ashino M, Uchihashi T, Yokoyama K, Sugawaraa Y, Moritab S, Ishikawaa M 2000 Applied Surface Science 157 212
[10] Hebenstreit E L, Hebenstreit W, Diebold U 2000 Surface Science 461 87
[11] Wang Y J, Wang C Y, Wang S Y 2011 Chin. Phys. B 20 036801
[12] Asari E, Souda R 2004 Solid State Communications 129 15
[13] Cui W Y, Liu Z Z, Jiang Y J, Wang N, Feng J K 2012 Acta Chim. Sinica 70 2049 (in Chinese) [崔文颖, 刘子忠, 蒋亚军, 王娜, 封继康 2012 化学学报 70 2049]
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[15] Xiao B, Feng J, Chen J C, Yan J K, Gan G Y 2008 Acta Phys. Sin. 57 3769 (in Chinese) [肖冰, 冯晶, 陈敬超, 严继康, 甘国友 2008 57 3769]
[16] Wu X Y, Selloni A, Nayak S 2004 J. Chem Phys. 120 4512
[17] Dan C, John T 2002 J. Phys. Chem. B 106 6184
[18] Wang Y 2005 Acta Chim. Sin. 63 1023 (in Chinese) [汪洋 2005 化学学报 63 1023]
[19] Wang Y, Meng L 2005 Acta Phys. Sin. 54 2207 (in Chinese) [汪洋, 孟亮 2005 54 2207]
[20] Linsebigler A, Lu G Q, Yates J 1995 Chem. Rev. 95 735
[21] Linsebigler A, Lu G Q, Yates J 1995 J. Chem. Phys. 103 9438
[22] Burnside S D, Shklover V, Barbé Barbe C, Comte P, Arendse F, Brooks K, Grätzel M 1998 Chem. Mater. 10 2419
[23] Labat F, Baranek P, Adamo C 2008 J. Chem. Theory Comput. 4 341
[24] Han Y, Liu C J, Ge Q F 2006 Phys. Chem. B 110 7463
[25] Shen X C 1992 Semiconductor spectrum and optical properties (2nd Ed.) (Beijing: Science Press) (in Chinese) [沈学础 1992 半导体光谱与光学性质(第2版)(北京: 科学出版社)]
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[1] Zhang X C, Zhao L J, Fan C M, Liang Z H, Han P D 2012 Acta Phys. Sin. 61 077101 (in Chinese) [张小超, 赵丽军, 樊彩梅, 梁镇海, 韩培德 2012 61 077101]
[2] Fujishima A, Honda K 1972 Nature 238 37
[3] Khan S U M, Al-Shahry M, Ingler Jr W B 2002 Science 297 2243
[4] Zhao J, Yang X D 2003 Building and Environment 38 645
[5] Yu X Y, Liang W, Cheng J J 2000 Bulletin of the Chinese Ceramic Society 1 53 (in Chinese)[于向阳, 梁文, 程继健 2000 硅酸盐通报 1 53]
[6] Chen X B, Liu L, Yu P Y, Peter Y Yu, Samuel S Mao 2011 Science 331 746
[7] Wang Y, Feng Q, Wang W H, Yue Y X 2012 Acta Phys. Sin. 61 193102 (in Chinese) [王寅, 冯庆, 王渭华, 岳远霞 2012 61 193102]
[8] O'Regan B, Grätzel M 1991 Nature 353 737
[9] Ashino M, Uchihashi T, Yokoyama K, Sugawaraa Y, Moritab S, Ishikawaa M 2000 Applied Surface Science 157 212
[10] Hebenstreit E L, Hebenstreit W, Diebold U 2000 Surface Science 461 87
[11] Wang Y J, Wang C Y, Wang S Y 2011 Chin. Phys. B 20 036801
[12] Asari E, Souda R 2004 Solid State Communications 129 15
[13] Cui W Y, Liu Z Z, Jiang Y J, Wang N, Feng J K 2012 Acta Chim. Sinica 70 2049 (in Chinese) [崔文颖, 刘子忠, 蒋亚军, 王娜, 封继康 2012 化学学报 70 2049]
[14] Simon D, Simon P, Bates Y 2003 Phys. Rev. B 67 035421
[15] Xiao B, Feng J, Chen J C, Yan J K, Gan G Y 2008 Acta Phys. Sin. 57 3769 (in Chinese) [肖冰, 冯晶, 陈敬超, 严继康, 甘国友 2008 57 3769]
[16] Wu X Y, Selloni A, Nayak S 2004 J. Chem Phys. 120 4512
[17] Dan C, John T 2002 J. Phys. Chem. B 106 6184
[18] Wang Y 2005 Acta Chim. Sin. 63 1023 (in Chinese) [汪洋 2005 化学学报 63 1023]
[19] Wang Y, Meng L 2005 Acta Phys. Sin. 54 2207 (in Chinese) [汪洋, 孟亮 2005 54 2207]
[20] Linsebigler A, Lu G Q, Yates J 1995 Chem. Rev. 95 735
[21] Linsebigler A, Lu G Q, Yates J 1995 J. Chem. Phys. 103 9438
[22] Burnside S D, Shklover V, Barbé Barbe C, Comte P, Arendse F, Brooks K, Grätzel M 1998 Chem. Mater. 10 2419
[23] Labat F, Baranek P, Adamo C 2008 J. Chem. Theory Comput. 4 341
[24] Han Y, Liu C J, Ge Q F 2006 Phys. Chem. B 110 7463
[25] Shen X C 1992 Semiconductor spectrum and optical properties (2nd Ed.) (Beijing: Science Press) (in Chinese) [沈学础 1992 半导体光谱与光学性质(第2版)(北京: 科学出版社)]
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