甲酸在Pt-Sn(111)/C合金表面吸附的量子化学研究  

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

作　　者：唐法威 郭为民[1] 唐楠楠[2] 裴俊彦[1] 许旋[3,4] 

机构地区：[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

出　　处：《物理化学学报》2013年第10期2198-2206,共9页Acta Physico-Chimica Sinica

基　　金：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~~

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、bridge、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.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）tC 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 CO is improved after doping with Sn.

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 

分 类 号：O641.12[理学—物理化学]