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根据密度泛函理论,采用广义密度近似,建立了水分子在SnO2(110)面不同吸附位的周期平板模型,研究了水分子在SnO2(110)表面的吸附特性.结果表明:发生在Sn5C吸附位的水分子平行于表面和水分子以H原子向上垂直于表面的两种吸附方式为稳定吸附.对两种稳定吸附方式下电子态密度及电荷转移进行了分析,发现两种吸附方式均使体系费米能向高能量方向移动,同时两种方式下水分子向SnO2表面提供的电子数分别为0.09 e和0.08 e.提出水分子与CO分子对表面同一吸附点存在着竞争吸附,是湿度影响CO气体传感器电导灵敏度的主要原因.
According to the density functional theory (DFT), a periodic plate model of water molecules adsorbed on the SnO2 (110) surface was established by generalized density approximation. The adsorption properties of water molecules on SnO2 (110) surface were investigated. The adsorption of water molecules parallel to the surface and water molecules with H atom up perpendicular to the surface is a stable adsorption.The electronic density of states and charge transfer under two stable adsorption modes are analyzed and it is found that both adsorption modes The system Fermi can move toward higher energy, and the numbers of electrons supplied by water molecules to SnO2 surface are 0.09 e and 0.08 e respectively in the two ways. It is proposed that water molecule and CO molecule have competitive adsorption on the same adsorption site on the surface, which is affected by humidity CO gas sensor conductivity sensitivity of the main reasons.