(509ac) Probing the Dynamic Surface Reconstruction in Non-Stoichiometric Mixed Metal Oxides during Electrochemical Oxygen Evolution

The progress in electrochemical oxygen evolution reaction (OER) is critical toward advancements in H₂O electrolyzers¹, metal-air batteries², and electrochemical fuel synthesis routes via CO₂ reduction. Therefore, the development of highly efficient and stable catalytic systems for this reaction remains key toward a sustainable, renewable-based energy landscape. While metal oxides have shown promising activity for OER, they are often confronted by severe cationic dissolution leading to surface reconstruction during OER.^3-5 Such implication hints into the dynamic nature of catalytic active sites during OER, indicating that both activity and stability should be considered when designing effective OER electrocatalysts.⁵ In this presentation, we focus on providing insights on the mechanism that governs the dynamic surface reconstruction of non-stochiometric mixed metal oxides with a general formula of A_n+1B_nO_3n+1 (n = 1 and n = ) during OER. Using a combination of electrochemical measurements, mass spectrometry, and X-ray based spectroscopic techniques, we probe the effects of key parameters, such as, starting oxide composition (electrode surface) and nature of the electrolyte (solvated double layer) on the oxide restructuring and activity. These findings provide insights toward identifying ways to design robust OER electrocatalysts.

References:

(1) Gu, X.K., et al., J. Catal. 2020, 388, 130−140.

(2) Gu, X.K., et al., Chem. Mater. 2018, 30, 9, 2860−2872.

(3) Forslund, R.P., et al., Nat. Commun. 2018, 9, 3150.

(4) Seitz, L.C., et al., Science 2016, 353, 1011−1014.

(5) Chung, D.Y., et al., Nat. Energy. 2020, 5, 222−230.