Engendering Unprecedented Activation of Oxygen Evolution via Rational Pinning of Ni Oxidation State in Prototypical Perovskite : Close Juxtaposition of Synthetic Approach and Theoretical Conception

Rational optimization of the OER activity of catalystsbased on LaNiO3 oxide is achieved by maximizing the presence of trivalent Ni in the surface structure. DFT investigations of the LaNiO3catalyst and surface structures related to it predict an improvement inthe OER activity for these materials to levels comparable with the topof the OER volcano if the La content is minimized while the oxidationstate of Ni is maintained. These theoretically predicted structures ofhigh intrinsic OER activity can be prepared by a templated spray-freeze freeze-drying synthesis followed by a simple postsynthesisexfoliation-like treatment in acidic media. These nanocrystallineLaNiO3-related materials confirm the theoretical predictions, showinga dramatic improvement in OER activity. The exfoliated surfacesremain stable in OER catalysis, as shown by an in-operando ICP-OESstudy. The unprecedented OER activation of the synthesized LaNiO3-based materials is related to a close juxtaposition of the theoretical conception of ideal structural motifs and the ability to engendersuch motifs using a unique synthetic procedure, both principally related to stabilization and pinning of the Ni oxidation state within the local coordination environment of the perovskite structure.