First‐Principles Investigation of the Relevant Surfaces Exposed by Polycrystalline LaFeO 3

A systematic comparison of surface energy values computed over a series of possible surfaces and terminations exposed by lanthanum orthoferrite (LaFeO 3 ) was performed for elucidating the nature of the exposed surfaces of LaFeO 3 ‐based three way catalysts. Surface reconstruction of polar surfaces was attempted, which did change the ranking of the most stable surfaces. Indeed, the non‐polar (1 2 1) and (1 0 0) surfaces were found to remain the most stable ones in vacuum. The relative stability of surfaces was also questioned when a partial pressure of water was applied, as is expected under the operating conditions of three‐way catalysis. Our results show that the predominance of (1 2 1) and (1 0 0) surfaces is even strengthened upon water exposure.