| Affiliation: | 1. Química de Recursos Energéticos y Medio Ambiente, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, 050010 Medellín, Colombia;2. Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 USA;3. Química de Recursos Energéticos y Medio Ambiente, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, 050010 Medellín, Colombia Current affiliation: Center for Materials Research, Institute of Physical Chemistry,, Justus-Liebig-University, Heinrich-Buff-Ring 17, 35392 Giessen, Germany;4. Grupo de Estado Sólido, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, 050010 Medellín, Colombia |
| Abstract: | There is an ongoing effort to replace rare and expensive noble-element catalysts with more abundant and less expensive transition metal oxides. With this goal in mind, the intrinsic defects of a rhombohedral perovskite-like structure of LaMnO3 and their implications on CO catalytic properties were studied. Surface thermodynamic stability as a function of pressure (P) and temperature (T) were calculated to find the most stable surface under reaction conditions (P=0.2 atm, T=323 K to 673 K). Crystallographic planes (100), (111), (110), and (211) were evaluated and it was found that (110) with MnO2 termination was the most stable under reaction conditions. Adsorption energies of O2 and CO on (110) as well as the effect of intrinsic defects such as Mn and O vacancies were also calculated. It was found that O vacancies favor the interaction of CO on the surface, whereas Mn vacancies can favor the formation of carbonate species. |
