SOFC复合阳极中的Cu在CeO_2表面上沉积的密度泛函研究

Deposition of Cu Contained in Composite SOFC Anode on CeO_2 Surface:A Density Functional Study

对固体氧化物燃料电池中的Cu-CeO2/YSZ复合阳极中的Cu在CeO2表面上沉积进行了密度泛函研究。Cu在CeO2的高对称性(101 0)表面的生长,首先键合于表面悬挂键或者表面成键轨道上,经过一次重排,表面的Cu层逐渐开始紊乱,变得凹凸不平并最终生长为三维团簇。对于(112 0)面,Cu初始只能键合于CeO2表面的悬挂键,然后生长为不规则的之字形结构、二维条带、二维岛并最终生长为扁平的团簇。Cu与CeO2之间存在很强的作用,在同一个吸附量下,有时可能存在多种构型,其活化能一般很低,沉积的Cu可在这些构型间来回迁移。很多位于CeO2 101 0))和(112 0)表面的Cu都带有略微的正价态,为可能的活性相,这些带正电荷的Cu有助于对燃料气的络合活化。

Density Functional Theory was used to study the deposition of Cu contained in the Cu-CeO2/YSZ Cu composite anode of the solid oxide fuel on the CeO2 surface.The Cu growth inu layer began to disorder and became uneven and ultimately grew into three-dimensional clusters.For the（112 0） surface,Cu was the high-symmetry CeO2 surface was achieved by first bonding itself to the dangling bonds or the bond orbitals at the surface;after a rearrangement,the surface C initially bonded only to dangling bonds at the CeO2 surface to form irregular zigzag structures,two-dimensional bands and two-dimensional islands which eventually grew into flat clusters.With a strong interaction between Cu and CeO2,the same adsorbance may sometimes produce a variety of configurations,the activation energy is generally low,and the deposited Cu can move back and forth between these configurations.Many deposited Cu ions on CeO2（101 0） and（112 0） surfaces are slightly positive,probably in an active phase,and the positively charged Cu complexes can contribute to the activation of the fuel gas.