Lattice Oxygen Activation through Deep Oxidation of Co₄N by Jahn-Teller-Active Dopants for Improved Electrocatalytic...

Triggering the lattice oxygen oxidation mechanism is crucial for improving oxygen evolution reaction (OER) performance, because it could bypass the scaling relation limitation associated with the conventional adsorbate evolution mechanism through the direct formation of oxygen-oxygen bond. High-valence transition metal sites are favorable for activating the lattice oxygen, but the deep oxidation of pre-catalysts suffers from a high thermodynamic barrier. Here, taking advantage of the Jahn-Teller (J-T) distortion induced structural instability, we incorporate high-spin Mn³⁺ ( $$ ) dopant into Co₄N. Mn dopants enable a surface structural transformation from Co₄N to CoOOH, and finally to CoO₂, as observed by various in situ spectroscopic investigations. Furthermore, the reconstructed surface on Mn-doped Co₄N triggers the lattice oxygen activation, as evidenced experimentally by pH-dependent OER, tetramethylammonium cation adsorption and online electrochemical mass spectrometry measurements of ¹⁸O-labelled catalysts. In general, this work not only offers the introducing J-T effect approach to regulate the structural transition, but also provides an understanding about the influence of the catalyst's electronic configuration on determining the reaction route, which may inspire the design of more efficient catalysts with activated lattice oxygen.