Atomic-scale insights into surface reconstruction and transformation in Co-Cr spinel oxides during the oxygen evolution reaction

作者：Biao He, Pouya Hosseini, Tatiana Priamushko, Oliver Trost, Eko Budiyanto, Christoph J. Bondue, Jonas Schulwitz, Aleksander Kostka, Harun Tüysüz, Martin Muhler, Serhiy Cherevko, Kristina Tschulik, Tong Li · 发表于：Nature Communications · 年份：2025 · DOI：10.1038/s41467-025-65626-x · 被引用次数：35 · 研究领域：Electrocatalysts for Energy Conversion、Nanoporous metals and alloys、Advanced Electron Microscopy Techniques and Applications

Abstract Optimizing the activity and longevity of oxygen evolution reaction (OER) electrocatalysts requires an atomic-scale understanding of multiple reconstruction and transformation processes occurring in the surface and sub-surface regions of the electrocatalyst. Herein, a multimodal method combining X-ray absorption fine structure and photoemission spectroscopy, in situ Raman spectroscopy, transmission electron microscopy and atom probe tomography with electrochemical measurements is employed to unveil how the changes in oxidation states, atomic coordination, structure and composition on ~20 nm CoCr 2 O 4 and Co 2 CrO 4 spinel nanoparticle surfaces affect OER activity and stability in alkaline media. CoCr 2 O 4 undergoes an activation process and subsequently retains high OER activity for extended durations. The activation of CoCr 2 O 4 is induced by a steady and substantial Cr dissolution that facilitates bulk incorporation and intercalation of hydroxide ions, coupled with the highly reversible ( $${{{{\rm{Co}}}}}_{{{{\rm{Td}}}}}^{{{{\rm{II}}}}}$$ Co Td II ,Cr)(OH) 2 ↔ ( $${{{{\rm{Co}}}}}_{{{{\rm{Oct}}}}}^{{{{\rm{III}}}}}$$ Co Oct III ,Cr)OOH transformation, which enhances OER activity and stability . In comparison, a ~ 2 nm thick amorphous self-limiting Cr-based (oxy)hydroxide forms on Co 2 CrO 4 upon cycling, contributing to OER activity. As OER proceeds, such Cr-based (oxy)hydroxide layers on Co 2 CrO 4 are depleted ...