Tapia-P Juan, Cao Yipeng, Gallego Jaime, Osorio-Guillén Jorge M, Morgan Dane, Espinal Juan F
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.
Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Chemphyschem. 2022 Jun 3;23(11):e202200152. doi: 10.1002/cphc.202200152. Epub 2022 Apr 28.
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 LaMnO 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 MnO termination was the most stable under reaction conditions. Adsorption energies of O 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.
人们正在努力用更丰富、更便宜的过渡金属氧化物取代稀有且昂贵的贵金属元素催化剂。出于这一目标，研究了类菱面体钙钛矿结构的LaMnO的固有缺陷及其对CO催化性能的影响。计算了作为压力（P）和温度（T）函数的表面热力学稳定性，以找出反应条件（P = 0.2 atm，T = 323 K至673 K）下最稳定的表面。评估了晶体平面（100）、（111）、（110）和（211），发现在反应条件下，以MnO终止的（110）是最稳定的。还计算了O和CO在（110）上的吸附能以及诸如Mn和O空位等固有缺陷的影响。结果发现，O空位有利于CO在表面的相互作用，而Mn空位则有利于碳酸盐物种的形成。
