H_2分子在LaFeO_3表面吸附的第一性原理研究
|
摘要
基于密度泛函理论的第一性原理方法,通过计算表面能确定La Fe O_3(010)表面为最稳定的吸附表面,研究了H_2分子在La Fe O_3(010)表面的吸附性质。La Fe O_3(010)表面存在La O和Fe O_2两种终止表面,但吸附主要发生在Fe O_2终止表面,由于La Fe O_3(010)表面弛豫的影响,使得凹凸不平的表面层增加了表面原子与H原子的接触面积,表面晶胞的纵向体积增加约2.5%,有利于H原子向晶体内扩散。研究发现,H_2分子在La Fe O_3(010)表面主要存在3种化学吸附方式:第一种吸附发生在O-O桥位,2个H原子分别吸附在2个O原子上,形成2个-OH基,这是最佳吸附位置,此时H原子与表面O原子的作用主要是H1s与O_2p轨道杂化作用的结果,H-O之间为典型的共价键。H_2分子的解离能垒为1.542 e V,说明表面需要一定的热条件,H_2分子才会发生解离吸附;第二种吸附发生在Fe-O桥位,1个H原子吸附在O原子上形成1个-OH基,另一个H原子吸附在Fe原子上形成金属键;第三种吸附发生在O顶位,2个H原子吸附在同一个O原子上,形成H_2O分子,此时H_2O分子与表面形成物理吸附,H_2O分子逃离表面后容易形成氧空位。此外,H_2分子在La Fe O_3(010)表面还可以发生物理吸附。
Based on the first principles calculations, the adsorption properties of H_2 molecules on La Fe O_3(010)surface are studied after the(010) surface was confirmed as the most stable surface. La Fe O_3(010) surface consists of La O and Fe O_2 terminated surfaces, but the adsorption mainly occurs on the Fe O_2 terminated surface.Due to the surface relaxation, the contact area on the uneven surface lay between surface atoms and H atoms increased, and resulted into about 2.5% increase of the longitudinal volume of the unit cell surface which is beneficial to the H atoms diffusion within the crystal. The results indicate that, there are three kinds of chemical adsorption modes of H_2 molecules on the surface of La Fe O_3(010): The best adsorption mode is that two H atoms are adsorbed to the two surface O atoms respectively, forming two-OH groups. At this position, the typical covalent bonds between H and surface O formed through the orbital hybridization of H1 s and O_2 p. The energy barrier of H_2 molecules dissociation is about 1.542 e V, indicating that the dissociative adsorption can be occurred only under certain thermal condition. The second mode is that one H atom adsorbed on the surface O atom,forming an-OH group, while the other H atom is adsorbed to the Fe atoms, forming a metal bond. The third mode is that two H atoms are adsorbed to the same surface O atom to form H_2 O molecules which is physically adsorbed on the surface, but the surface oxygen vacancies can be easily formed after the H_2 O molecules escaped from the surface. In addition, H_2 molecules also can be physically adsorbed on La Fe O_3(010) surface.
Based on the first principles calculations, the adsorption properties of H_2 molecules on La Fe O_3(010)surface are studied after the(010) surface was confirmed as the most stable surface. La Fe O_3(010) surface consists of La O and Fe O_2 terminated surfaces, but the adsorption mainly occurs on the Fe O_2 terminated surface.Due to the surface relaxation, the contact area on the uneven surface lay between surface atoms and H atoms increased, and resulted into about 2.5% increase of the longitudinal volume of the unit cell surface which is beneficial to the H atoms diffusion within the crystal. The results indicate that, there are three kinds of chemical adsorption modes of H_2 molecules on the surface of La Fe O_3(010): The best adsorption mode is that two H atoms are adsorbed to the two surface O atoms respectively, forming two-OH groups. At this position, the typical covalent bonds between H and surface O formed through the orbital hybridization of H1 s and O_2 p. The energy barrier of H_2 molecules dissociation is about 1.542 e V, indicating that the dissociative adsorption can be occurred only under certain thermal condition. The second mode is that one H atom adsorbed on the surface O atom,forming an-OH group, while the other H atom is adsorbed to the Fe atoms, forming a metal bond. The third mode is that two H atoms are adsorbed to the same surface O atom to form H_2 O molecules which is physically adsorbed on the surface, but the surface oxygen vacancies can be easily formed after the H_2 O molecules escaped from the surface. In addition, H_2 molecules also can be physically adsorbed on La Fe O_3(010) surface.
引文
[1]Sakintuna B,Lamaridarkrim F,Hirscher M.Int.J.Hydrogen Energy,2007,32(9):1121-1140
[2]Reilly J J,Adzic G D,Johnson J R,et al.J.Alloys Compd.,1999:293-295,569-582
[3]Rongeat C,Grosjean M H,Ruggeri S,et al.J.Power Sources,2006,158(1):747-753
[4]Esaka T,Sakaguchi H,Kobayashi S.Solid State Ionics,2004,166(3/4):351-357
[5]XIA Xi(夏熙),LI Xue-Qin(李学琴),CUI Jing-Jie(崔静洁),et al.Acta Chim.Sinica(化学学报),2004,62(23):2355-2360
[6]Wang Q,Deng G,Chen Z Q,et al.J.Appl.Phys.,2013,113(5):053305
[7]Wang Q,Chen Z Q,Chen Y G,et al.Ind.Eng.Chem.Res.,2012,51(37):11821-11827
[8]Deng G,Chen Y G,Tao M D,et al.Electrochim.Acta,2009,54(15):3910-3914
[9]DENG Gang(邓刚),CHEN Yun-Gui(陈云贵),TAO Ming-Da(陶明大),et al.Acta Chim.Sinica(化学学报),2009,67(17):2001-2004
[10]Deng G,Chen Y G,Tao M D,et al.Electrochim.Acta,2010,55(3):1120-1124
[11]Liu Y,Liu Y N,Ma J F,et al.J.Power Sources,2010,195(7):1854-1858
[12]Ma J,Liu Y,Liu Y,et al.Fuel Cells,2008,8(6):394-398
[13]Ibrahim S M.Korean J.Chem.Eng.,2014,31(10):1792-1797
[14]Lim D K,Im H N,Singh B,et al.Electrochim.Acta,2013,102:393-399
[15]Lim D K,Im H N,Kim J,et al.J.Phys.Chem.Solids,2013,74(1):115-120
[16]Mandal T K,Sebastian L,Gopalakrishnan J,et al.Mater.Res.Bull.,2014,39(14/15):2257-2264
[17]WANG Zhong-Lin(王中林),KANG Zhen-Chuan(康振川).Structure Evolution and Structure Analysis of Functional and Intelligent Materials(功能与智能材料结构演化与结构分析).Beijing:Science Press,2002:87
[18]Patrakeeva M V,Bahteevaa J A,Mitberga E B,et al.J.Solid State Chem.,2003,172(1):219-231
[19]Milman V,Winkler B,White J A,et al.Int.J.Quantum Chem.,2000,77(5):895-910
[20]Perdew J P,Burke K,Ernzerhof M.Phys.Rev.Lett.,1996,77(18):3865-3868
[21]Vanderbilt D.Phys.Rev.B,1990,41(11):7892-7895
[22]Sun J,Wang H T,He J L,et al.Phys.Rev.B,2005,71(12):125132
[23]Taguchi H,Masunaga Y,Hirota K,et al.Mater.Res.Bull.,2005,40(5):773-780
[24]Chiou W C,Carter E A.Surf.Sci.,2003,530(1/2):88-100
[25]Liu X,Hu J F,Cheng B,et al.Sens.Actuators B,2009,139(2):520-526
[26]Sun L H,Hu J F,Gao F,et al.Physica B:Condens.Matter.,2011,406(21):4105-4108
[27]Barbero B P,Gamboa J A,Cadús L E.Appl.Catal.B,2006,65(1/2):21-30
[28]Aono H,Traversa E,Sakamoto M,et al.Sens.Actuators B,2003,94(2):132-139
[29]LIU Yi-Xin(刘奕新),ZHENG Ding-Shan(郑定山),ZHANG Yi(张怡),et al.Trans.Nonferrous Met.Soc.(中国有色金属学报),2008,18(9):1692-1698
[30]DU Rui(杜瑞),CHEN Yu-Hong(陈玉红),ZHANG Zhi-Long(张致龙),et al.Acta Chim.Sinica(化学学报),2011,69(10):1167-1172
[31]Chen Y H,Zhang B W,Yang L,et al.J.Nanomater.,2014,2014:1-8
[32]Kresse G,Hafner J.Surf.Sci.,2000,459(3):287-302
[33]LUO Wen-Hua(罗文华),MENG Da-Qiao(蒙大桥),LI Gan(李赣),et al.Acta Phys.Sinica(物理学报),2008,57(1):0160-0165
[34]Lie G C,Clementi E.Phys.Rev.A,1986,33(4):2679-2693
[35]Becke A D,Edgecombe K E.J.Chem.Phys.,1990,92(9):5397-5403
[36]Burdett J K,Mc Cormick T A.J.Phys.Chem.A,1998,102(31):6366-6372
[37]Sánchez-Benítez J,Martínez-Lope M J,Alonso J A.J.Appl.Phys.,2010,107(10):103904
[2]Reilly J J,Adzic G D,Johnson J R,et al.J.Alloys Compd.,1999:293-295,569-582
[3]Rongeat C,Grosjean M H,Ruggeri S,et al.J.Power Sources,2006,158(1):747-753
[4]Esaka T,Sakaguchi H,Kobayashi S.Solid State Ionics,2004,166(3/4):351-357
[5]XIA Xi(夏熙),LI Xue-Qin(李学琴),CUI Jing-Jie(崔静洁),et al.Acta Chim.Sinica(化学学报),2004,62(23):2355-2360
[6]Wang Q,Deng G,Chen Z Q,et al.J.Appl.Phys.,2013,113(5):053305
[7]Wang Q,Chen Z Q,Chen Y G,et al.Ind.Eng.Chem.Res.,2012,51(37):11821-11827
[8]Deng G,Chen Y G,Tao M D,et al.Electrochim.Acta,2009,54(15):3910-3914
[9]DENG Gang(邓刚),CHEN Yun-Gui(陈云贵),TAO Ming-Da(陶明大),et al.Acta Chim.Sinica(化学学报),2009,67(17):2001-2004
[10]Deng G,Chen Y G,Tao M D,et al.Electrochim.Acta,2010,55(3):1120-1124
[11]Liu Y,Liu Y N,Ma J F,et al.J.Power Sources,2010,195(7):1854-1858
[12]Ma J,Liu Y,Liu Y,et al.Fuel Cells,2008,8(6):394-398
[13]Ibrahim S M.Korean J.Chem.Eng.,2014,31(10):1792-1797
[14]Lim D K,Im H N,Singh B,et al.Electrochim.Acta,2013,102:393-399
[15]Lim D K,Im H N,Kim J,et al.J.Phys.Chem.Solids,2013,74(1):115-120
[16]Mandal T K,Sebastian L,Gopalakrishnan J,et al.Mater.Res.Bull.,2014,39(14/15):2257-2264
[17]WANG Zhong-Lin(王中林),KANG Zhen-Chuan(康振川).Structure Evolution and Structure Analysis of Functional and Intelligent Materials(功能与智能材料结构演化与结构分析).Beijing:Science Press,2002:87
[18]Patrakeeva M V,Bahteevaa J A,Mitberga E B,et al.J.Solid State Chem.,2003,172(1):219-231
[19]Milman V,Winkler B,White J A,et al.Int.J.Quantum Chem.,2000,77(5):895-910
[20]Perdew J P,Burke K,Ernzerhof M.Phys.Rev.Lett.,1996,77(18):3865-3868
[21]Vanderbilt D.Phys.Rev.B,1990,41(11):7892-7895
[22]Sun J,Wang H T,He J L,et al.Phys.Rev.B,2005,71(12):125132
[23]Taguchi H,Masunaga Y,Hirota K,et al.Mater.Res.Bull.,2005,40(5):773-780
[24]Chiou W C,Carter E A.Surf.Sci.,2003,530(1/2):88-100
[25]Liu X,Hu J F,Cheng B,et al.Sens.Actuators B,2009,139(2):520-526
[26]Sun L H,Hu J F,Gao F,et al.Physica B:Condens.Matter.,2011,406(21):4105-4108
[27]Barbero B P,Gamboa J A,Cadús L E.Appl.Catal.B,2006,65(1/2):21-30
[28]Aono H,Traversa E,Sakamoto M,et al.Sens.Actuators B,2003,94(2):132-139
[29]LIU Yi-Xin(刘奕新),ZHENG Ding-Shan(郑定山),ZHANG Yi(张怡),et al.Trans.Nonferrous Met.Soc.(中国有色金属学报),2008,18(9):1692-1698
[30]DU Rui(杜瑞),CHEN Yu-Hong(陈玉红),ZHANG Zhi-Long(张致龙),et al.Acta Chim.Sinica(化学学报),2011,69(10):1167-1172
[31]Chen Y H,Zhang B W,Yang L,et al.J.Nanomater.,2014,2014:1-8
[32]Kresse G,Hafner J.Surf.Sci.,2000,459(3):287-302
[33]LUO Wen-Hua(罗文华),MENG Da-Qiao(蒙大桥),LI Gan(李赣),et al.Acta Phys.Sinica(物理学报),2008,57(1):0160-0165
[34]Lie G C,Clementi E.Phys.Rev.A,1986,33(4):2679-2693
[35]Becke A D,Edgecombe K E.J.Chem.Phys.,1990,92(9):5397-5403
[36]Burdett J K,Mc Cormick T A.J.Phys.Chem.A,1998,102(31):6366-6372
[37]Sánchez-Benítez J,Martínez-Lope M J,Alonso J A.J.Appl.Phys.,2010,107(10):103904
© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |