过渡金属Cu、Cr掺杂TiO_2表面氧化性气体NO_2光学气敏传感特性
|
摘要
采用密度泛函理论(DFT)体系广义梯度近似(GGA)第一性原理平面波超软赝势方法,分析锐钛矿型TiO_2(101)表面吸附NO_2分子光学气敏传感的微观机理.结果表明:Cu和Cr原子易于掺入TiO_2(101)表面,掺杂表面能稳定地吸附NO_2分子且吸附后光学性质发生显著变化.表面吸附NO_2分子后,Cu掺杂TiO_2(101)表面对分子的吸附能最大,吸附后结构更稳定,分子与表面的距离最短.通过分析差分电荷密度和电荷布居数发现,NO_2分子与基底表面间发生电荷转移,转移电子数目:Cu掺杂表面>Cr掺杂表面>无掺杂表面.对比吸收光谱和反射光谱发现,在Cu掺杂表面吸附分子后,光学性质变化最明显,说明表面与吸附分子间氧化还原能力是决定光学气敏传感性能的核心因素.在过渡金属中,Cu与Cr都有4s价电子结构,其4s电子降低了材料表面氧空位的氧化性,增加了其还原性.对于氧化性气体,可以提升表面与分子的氧化还原作用,而Cu的4s电子更加活泼,从而光学气敏传感特性更加明显.因此,Cu掺杂的TiO_2对氧化性气体是一种较好的光学气敏传感材料.
With first-principles plane-wave ultrasoft pseudopotential method based on density functional(DFT) system, we analyze properties of optical gas sensor materials anatase TiO_2(101) surfaces with NO_2 adsorption. Cu and Cr atoms are easily doped on TiO_2(101) surface. Cu and Cr doped TiO_2(101) surfaces could absorbed NO_2 molecules steadily. After adsorption, material optical properties changed obviously. Cu doped TiO_2(101) surfaces have the highest adsorption energy and the shortest distance between surface and molecule. Analyzing charge density difference and charge population we found that charge transfer occurs between NO_2 molecule and material surface. Electron transfer number is as follows: Cu-doped surface>Cr-doped surface>Undoped surface. Comparing absorption and reflection spectra we found that Cu-doped surface optical properties changed obviously. Redox capacity between surfaces and molecules decided optical gas sensing propertiess. Cu and Cr has 4 s valence electron structure which could reduce materials oxygen vacancies oxidative properties. For oxidizing gases, 4 s electron could increase surfaces and molecules redox effect. Cu 4 s electron is more active. It indicates that Cu doped TiO_2 is a good optical gas sensor material for oxidizing gases.
With first-principles plane-wave ultrasoft pseudopotential method based on density functional(DFT) system, we analyze properties of optical gas sensor materials anatase TiO_2(101) surfaces with NO_2 adsorption. Cu and Cr atoms are easily doped on TiO_2(101) surface. Cu and Cr doped TiO_2(101) surfaces could absorbed NO_2 molecules steadily. After adsorption, material optical properties changed obviously. Cu doped TiO_2(101) surfaces have the highest adsorption energy and the shortest distance between surface and molecule. Analyzing charge density difference and charge population we found that charge transfer occurs between NO_2 molecule and material surface. Electron transfer number is as follows: Cu-doped surface>Cr-doped surface>Undoped surface. Comparing absorption and reflection spectra we found that Cu-doped surface optical properties changed obviously. Redox capacity between surfaces and molecules decided optical gas sensing propertiess. Cu and Cr has 4 s valence electron structure which could reduce materials oxygen vacancies oxidative properties. For oxidizing gases, 4 s electron could increase surfaces and molecules redox effect. Cu 4 s electron is more active. It indicates that Cu doped TiO_2 is a good optical gas sensor material for oxidizing gases.
引文
[1] LEE H U, LEE S C, CHOI S H, et al. Highly visible-light active nanoporous TiO2 photocatalysts for efficient solar photocatalytic applications [J]. Applied Catalysis B: Environmental, 2013, 129: 106-113.
[2] FENG Q, YUE Y X, WANG Y, et al. Study on optical and electronic properties of Mn-N co-doped anatase titanium dioxide [J]. Laser & Optoelectronics Progress, 2013, 50: 061601.
[3] LIN Y, ZHOU X W, XIAO X R, et al. Research progress of solid state dye-sensitized TiO2 nanocrystalline thin film solar cells [J]. Science & Technology Review, 2006, 216(24): 11-14.
[4] YANG J Y, CHEN X Q, ZHANG J S, et al. Study on application of nanometer TiO2 as photocatalyst in the field of environmental protection new progress [J]. Fine Chemical Intermediates, 2002, 32(6): 5-9.
[5] ZHANG Q H. Titanium dioxide nano materials and its research progress in clean energy technology [J]. Journal of Inorganic Materials, 2012, 27(1): 1-10.
[6] LI Y J. The characteristics and application of titanium dioxide in food safety [J]. China Food Safty, 2008, 1010643: 58-59.
[7] XU C Y. Application of nano titanium dioxide in sunscreen cosmetics [J]. YuNan Chemical Technology, 2014, 31(3): 36-38.
[8] CUI W Y, LIU Z Z, JIANG Y J, et al. Study on trifluoroacetic acid adsorbed on TiO2 surface with density function theory [J]. Acta Chimica Sinica, 2012, 70: 2049-2058.
[9] FENG Q. First principles study on properties of anatase TiO2 vacancies [J]. Journal of Chongqing Normal University, 2009, 26(1): 78-81.
[10] SONG D W, NIU Y, XIAO L O, et al. Structural, electronic and magnetic properties of Mn-doped ZnS(110) surfaces: First-principles study [J]. Chinese Journal of Computational Physics, 2012, 29(2): 277-284.
[11] HEBNESTREIT W, RUZYCKI N, HERMAN G S, et al. Scanning tunneling microscopy investigation of the TiO2 anatase (101) surface [J]. Physical Review B, 2000, 62: 334-336.
[12] 柳清. 石墨烯吸附NO2的第一性原理研究[D]. 北京:北京理工大学, 2016.
[13] CHEN X Y, FENG Q, ZHOU Q. Effect of Cu and non-metal double acceptor impurity level cooperative action on optical properties of anatase TiO2[J]. Chinese Journal of Computational Physics, 2017, 34(1): 99-108.
[14] FENG Q, WANG Y, WANG W H, et al. First-principles study of electronic and optical properties of N-S co-doped rutile TiO2[J]. Chinese Journal of Computational Physics, 2012, 29(4): 593-600.
[15] RIEBOLDT F, BECHSTEIN R, BESENBACHER F, et al. Vicinal rutile TiO2 surfaces and their interactions with O2[J]. The Journal of Physical Chemistry C, 2014, 118 (7), 3620-3628.
[16] PERDEW J P, RUZSINSZKY A, CSONKA G I, et al. Restoring the density-gradient expansion for exchange in solids and surfaces [J]. Physical Review Letters, 2008, 100(13): 136406.
[17] LIU B, GU M, LIU X L, et al. First-principles study of fluorine-doped zinc oxide [J]. Applied Physics Letters, 2010, 97(12): 122101-1-122101-3.
[18] YOU H, LIU C J, Ge Q F. Interaction of Pt clusters with the anatase TiO2(101) surface: A first principles study [J]. The Journal of Physical Chemistry B, 2006, 110(14): 7463-7472.
[19] SHEN X C. Semiconductor spectrum and optical properties[M]. 2nd ed. Beijing: Science Press, 1992.
[2] FENG Q, YUE Y X, WANG Y, et al. Study on optical and electronic properties of Mn-N co-doped anatase titanium dioxide [J]. Laser & Optoelectronics Progress, 2013, 50: 061601.
[3] LIN Y, ZHOU X W, XIAO X R, et al. Research progress of solid state dye-sensitized TiO2 nanocrystalline thin film solar cells [J]. Science & Technology Review, 2006, 216(24): 11-14.
[4] YANG J Y, CHEN X Q, ZHANG J S, et al. Study on application of nanometer TiO2 as photocatalyst in the field of environmental protection new progress [J]. Fine Chemical Intermediates, 2002, 32(6): 5-9.
[5] ZHANG Q H. Titanium dioxide nano materials and its research progress in clean energy technology [J]. Journal of Inorganic Materials, 2012, 27(1): 1-10.
[6] LI Y J. The characteristics and application of titanium dioxide in food safety [J]. China Food Safty, 2008, 1010643: 58-59.
[7] XU C Y. Application of nano titanium dioxide in sunscreen cosmetics [J]. YuNan Chemical Technology, 2014, 31(3): 36-38.
[8] CUI W Y, LIU Z Z, JIANG Y J, et al. Study on trifluoroacetic acid adsorbed on TiO2 surface with density function theory [J]. Acta Chimica Sinica, 2012, 70: 2049-2058.
[9] FENG Q. First principles study on properties of anatase TiO2 vacancies [J]. Journal of Chongqing Normal University, 2009, 26(1): 78-81.
[10] SONG D W, NIU Y, XIAO L O, et al. Structural, electronic and magnetic properties of Mn-doped ZnS(110) surfaces: First-principles study [J]. Chinese Journal of Computational Physics, 2012, 29(2): 277-284.
[11] HEBNESTREIT W, RUZYCKI N, HERMAN G S, et al. Scanning tunneling microscopy investigation of the TiO2 anatase (101) surface [J]. Physical Review B, 2000, 62: 334-336.
[12] 柳清. 石墨烯吸附NO2的第一性原理研究[D]. 北京:北京理工大学, 2016.
[13] CHEN X Y, FENG Q, ZHOU Q. Effect of Cu and non-metal double acceptor impurity level cooperative action on optical properties of anatase TiO2[J]. Chinese Journal of Computational Physics, 2017, 34(1): 99-108.
[14] FENG Q, WANG Y, WANG W H, et al. First-principles study of electronic and optical properties of N-S co-doped rutile TiO2[J]. Chinese Journal of Computational Physics, 2012, 29(4): 593-600.
[15] RIEBOLDT F, BECHSTEIN R, BESENBACHER F, et al. Vicinal rutile TiO2 surfaces and their interactions with O2[J]. The Journal of Physical Chemistry C, 2014, 118 (7), 3620-3628.
[16] PERDEW J P, RUZSINSZKY A, CSONKA G I, et al. Restoring the density-gradient expansion for exchange in solids and surfaces [J]. Physical Review Letters, 2008, 100(13): 136406.
[17] LIU B, GU M, LIU X L, et al. First-principles study of fluorine-doped zinc oxide [J]. Applied Physics Letters, 2010, 97(12): 122101-1-122101-3.
[18] YOU H, LIU C J, Ge Q F. Interaction of Pt clusters with the anatase TiO2(101) surface: A first principles study [J]. The Journal of Physical Chemistry B, 2006, 110(14): 7463-7472.
[19] SHEN X C. Semiconductor spectrum and optical properties[M]. 2nd ed. Beijing: Science Press, 1992.