Ab-initio study of Sr-doping effects on nitric oxide adsorption on the LaO (001) surface of LaFeO3

作者：Kizaki Hidetoshi^*; Kusakabe Koichi

来源：Surface Science, 2012, 606(23-24): 1783-1789.

DOI：10.1016/j.susc.2012.07.043

• Ab-initio calculation
• (La,Sr)FeO3 surface
• Oxygen vacancy adsorption energy

Density-functional calculations of molecular nitric oxide (NO) on defective (La,Sr)O (001) surfaces of (La,Sr) FeO3-delta using slab models are performed to elucidate the oxygen vacancy formation problem on the LaO (001) surface of LaFeO3-delta.
From the estimation of the NO adsorption energy, NO adsorption is found on (La,Sr)O surfaces of (La-0.83, Sr-0.17)FeO3-delta with delta=0 or 0.25.
The absolute value of the NO adsorption energy shows a remarkable increase at oxygen vacancies in the top surface layer, where the nitrogen atoms of the adsorbed molecules are embedded in the first (La,Sr)O layer, because a bond with Fe in the second FeO2 layer is formed. Our data shows that Sr doping promotes formation of oxygen vacancies, which keep the NO adsorption ability high.
Thus, we conclude that if Sr doping increases the number of oxygen vacancy sites by a charge compensation effect. NO adsorption on LaFeO3 is enhanced, which provides an explanation for several experimental observations.

• 出版日期2012-12