采用基于广义梯度近似的投影缀加平面波(projector augmented wave)雁势和具有三维周期性边界条件的超晶胞模型,用第一性原理方法,计算并分析了Au在CeO2(110)和Zr掺杂的CeO2(110)面的吸附能,吸附结构和电子结构等特征.从而得出Zr掺杂对Au/CeO2(110)吸附体系的影响.结果表明:Zr的掺杂增大了Au在CeO2(110)面的吸附能,并改变了最强吸附位置,且导致了吸附体系中衬底结构较大的变化;Zr的掺杂使吸附体系引入了更为复杂的间隙态,使得Zr掺杂的吸附体系有更好的催化活性;Zr的掺杂使吸附原子Au的氧化程度加强,由无掺杂吸附体系中Au得到电子变为Zr掺杂吸附体系中的Au失去电子.以上结果有助于人们更清楚地了解三元催化剂中Zr掺杂的影响以及贵金属Au与CeO2-ZrO2混合氧化物的协同作用机理.
The adsorption of Au on the(110) surfaces of CeO2 and Zr-doped CeO2 were studied using projector-augmented wave(PAW) method based density-functional theory(DFT) within the gradient approximation(GGA) and with the inclusion of on-site Coulomb interaction(DFT+U).It is found that,due to the doping of Zr,the adsorption energies of Au are increased and the strongest adsorption geometry is altered.The doping of Zr results in larger distortion in the structure of the substrate,and enhances the catalytic activity of the Au/CeO2(110) system and the oxidization of Au.These results may lead to a better understanding for the Au/Zr-doped CeO2 catalysts and give some clues for improving the efficiency of the three-way catalysts(TWC).