基于密度泛函理论研究水在磷酸锂（100）表面的吸附

摘要

Lithium phosphate is an efficient catalyst for isomerization of propylene oxide.But we recently found that during the experiment after adsorbing water, the catalytic performance can be improved greatly.In order to find out what happened after adsorbing water, density functional theory ( DFT) with the generalized gradient approximation ( GGA-PBE) was used to study the adsorption of H2 O molecule on Li3PO 4 ( 100 ) surface at different sites.The calculated results indicated that water molecule was inclined to locate on the Li-Li bridge site with its H atom being attracted by the O atom of phosphate ion and its O atom adjacent to two Li ions when different adsorption energies and geometrical parameters were compared.Mulliken population analysis results showed that some electrons transfered from the substrate to water molecule.%磷酸锂是环氧丙烷异构化反应的一种高效的催化剂，经实验发现在吸附水之后磷酸锂催化性能有所提高。为了进一步了解水吸附的影响，我们运用广义梯度近似方法（GGA-PBE）研究了水分子在Li3PO4（100）表面不同吸附位点的吸附行为。通过比较不同吸附位的吸附能和几何构型参数发现：水分子倾向于吸附在Li-Li桥位上以氧端与表面邻近的两个Li原子相互作用，而H原子与磷酸根中的O原子结合。电荷布居分析结果为水分子的电荷数减少，而Li3 PO4表面的Li原子和O原子电荷数增加，表明水分子从Li3 PO4表面得到电子。