贵金属原子在CeO2(111)表面吸附的密度泛函理论研究

摘要

Adsorption behaviors of four typical noble metals (Au, Pd, Pt, and Rh) on the CeO2( 111) surface were systematically investigated by using density functional theory method. The results indicated that Au prefers to be adsorbed on the atop site, while Pd and Pt on the O-bridge site. Rh adsorbed on the 3-fold hollow site is the most stable configurations. When the noble metals are adsorbed on the atop site, the adsorption strength is in the order of Pt > Rh > Pd > Au. New electronic peaks are present between the Ce 4/and O 2p peaks when Pd, Pt, and Rh atoms are adsorbed on the CeO2( 111) surface, while no peak is found for the adsorption of Au; the d electronic peak of Au overlaps with the O 2/p peaks at -4 to -1 eV. According to the density of states (DOS) analysis, when Au is adsorbed on the atop site, Pd and Pt on the bridge site, and Rh on the 3-fold hollow site, their interactions with surface oxygen atoms on the CeO2 (111) surface are stronger than other configurations, which is in good agreement with the results of Bader charge population.%利用密度泛函理论系统研究了贵金属原子(Au、Pd、Pt和Rh)在CeO2( 111)表面的吸附行为.结果表明,Au吸附在氧顶位最稳定,Pd、Pt倾向吸附于氧桥位,而Rh在洞位最稳定.当金属原子吸附在氧顶位时,吸附强度依次为Pt ＞Rh＞ Pd＞Au.Pd、Pt与Rh吸附后在Ce 4 f、O2p电子峰间出现掺杂峰；Au未出现掺杂电子峰,其d电子峰与表面O2p峰在-4 -1 eV重叠.态密度分析表明,Au吸附在氧顶位、Pd与Pt吸附在桥位、Rh吸附在洞位时,金属与CeO2(111)表面氧原子作用较强,这与Bader电荷分析结果相一致.