物理化学学报 >> 2013, Vol. 29 >> Issue (10): 2198-2206.doi: 10.3866/PKU.WHXB201307294

理论与计算化学 上一篇    下一篇

甲酸在Pt-Sn(111)/C合金表面吸附的量子化学研究

唐法威1, 郭为民1, 唐楠楠2, 裴俊彦1, 许旋3,4   

  1. 1 广西科技大学生物与化学工程学院, 广西柳州 545006;
    2 成都纺织高等专科学校, 成都 611731;
    3 华南师范大学化学与环境学院, 广州 510006;
    4 华南师范大学, 教育部环境理论化学重点实验室, 广州 510006
  • 收稿日期:2013-06-15 修回日期:2013-07-26 发布日期:2013-09-26
  • 通讯作者: 郭为民 E-mail:guoweimin8@163.com
  • 基金资助:

    教育部科学技术研究重点项目(210163);广西自然科学基金(2010GXNSFA013045);广西科学研究与技术开发计划(桂科攻101420011);广西高校优秀人才计划(2012)资助项目

Quantum Chemical Study on the Adsorption of Formic on a Pt-Sn(111)/CAlloy Surface

TANG Fa-Wei1, GUO Wei-Min1, TANG Nan-Nan2, PEI Jun-Yan1, XU Xuan3,4   

  1. 1 College of Biological and Chemical Engineering, Guangxi University of Science and Techonology, Liuzhou 545006, Guangxi Zhuang Autonomous Region, P. R. China;
    2 Chengdu Textile College, Chengdu 611731, P. R. China;
    3 School of Chemistry and Environment, South China Normal University, Guangzhou 510006, P. R. China;
    4 Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, South China Normal University, Guangzhou 510006, P. R. China
  • Received:2013-06-15 Revised:2013-07-26 Published:2013-09-26
  • Contact: GUO Wei-Min E-mail:guoweimin8@163.com
  • Supported by:

    The project was supported by the Key Project of the Ministry of Education of China (210163), Natural Science Foundation of Guangxi Zhuang Autonomous Region, China (2010GXNSFA013045), Guangxi Scientific Research and Technology Development Projects, China (Guikegong 101420011), and Programfor Excellent Talents in Guangxi Higher Education Institutions, China (2012).

摘要:

采用周期平板模型, 结合密度泛函理论对HCOOH和CO在Pt-Sn(111)/C表面的top、brigde、hcp和fcc共计8个位点的吸附模型进行构型优化和能量计算, 并对吸附前后的频率、电荷、能带和态密度进行了研究. 计算结果表明fcc-Pt3是较为有利的吸附位点, Sn掺杂之后费米能级右移, 导带增宽, 价带和导带的位置略微降低, 合金表面电子结构变化利于甲酸的吸附解离催化, 可使甲酸燃料电池阳极催化性能显著提高. 通过催化剂表面的抗中毒分析, 发现CO在Pt-Sn(111)/C表面的吸附能以两种趋势下降, 阳极催化剂掺杂改性后抗CO中毒能力增强.

关键词: 直接甲酸燃料电池, Pt-Sn(111)/C表面, 密度泛函理论, 电子结构, 态密度

Abstract:

Density functional theory (DFT) and self-consistent periodic calculations were used to investigate the adsorption of formic acid (HCOOH) and carbon monoxide (CO) at eight sites, such as top, bridge, hcp and fcc, on a Pt-Sn(111)/C surface. The vibrational frequency, electric charge, energy band and density of states of HCOOH before and after adsorption on a Pt-Sn(111)/C surface were determined. The results show that before doping, the favored adsorption site for HCOOH and CO is the fcc-Pt3 site. After doping the surface with Sn, the Fermi level moves to the right, the conduction band broadens, and the valence and conduction bands lower slightly. The change of the electronic structure on Pt-Sn(111)/C promotes both the adsorption and dissociation of HCOOH, which can improve the performance of anode catalysts for direct formic acid fuel cells (DFAFCs). Based on the anti-poisoning analysis of the catalyst surface, it was also found that the adsorption energy of CO on Pt-Sn(111)/C surfaces is lower than that on Pt(111)/C ones. The results show that the adsorption energy of CO on Pt-Sn(111)/C decreases through two ways, and the anti-poisoning ability of the catalyst towards COis improved after doping with Sn.

Key words: Direct formic acid fuel cell, Pt-Sn(111)/C surface, Density functional theory, Electronic structure, Density of states

MSC2000: 

  • O646