J.P. Wang #, Y. Liu #, J.X. Mi *, Y.J. Ding, L.Z. Zhang, X.M. Su, J.X. Ma, Y. Wang, Y.J. Li, Y.Y. Xu and Z.-S. Wu *

Small, 2025, accepted.

Regulation of A-site vacancy and activation of lattice oxygen (Olatt) are crucial for maximizing the chemical properties of perovskites (ABO3) catalysts for functional applications. Herein, we report an effective La vacancy (VLa) creation strategy to activate surface Olatt species over two-dimensional (2D) ultrathin LaFeO3 (2D-U-LFO) nanosheets by introducing urea, which can precisely modulate their physicochemical properties and thus remarkably enhance catalysis and energy conver-sion. The contained surface VLa of 2D-U-LFO nanosheet generates more reduced Fe-O bonding and activated Olatt species, thereby the resulted 2D-U-LFO exhibits remarkably improved catalytic oxidation performance than that of pristine LaFeO3 and bulk LaFeO3 with acti-vated Olatt species. Further, 2D-U-LFO cathode for Li-O2 battery also displays higher specific capacity of 24251 mAh/g and longer cyclabil-ity of 1600 h than pristine LFO (10495 mAh/g, 200 h). We revealed theoretically that the surface VLa over LFO could promote the Li2O2 adsorption. This proposed strategy will pave a novel avenue to devel-op vacancy-meditated ABO3 in sheet structure for boosting functional applications.