Lee, Woong Hee Han, Man Ho Ko, Young-Jin Min, Byoung Koun Chae, Keun Hwa Oh, Hyung-Suk 2024-01-19T12:33:36Z 2024-01-19T12:33:36Z 2022-04-05 2022-02 2041-1723 https://pubs.kist.re.kr/handle/201004/115650 The phase and spin state affect catalytic activity of Co-based catalysts for oxygen evolution reaction. Herein, the authors demonstrate a simple reconstruction strategy to fabricate electrodes maintaining a Fe-CoOOH phase and an intermediate-spin state during catalysis. Computational calculations and experimental studies reveal that the CoOOH phase and the intermediate-spin (IS) state are the key factors for realizing efficient Co-based electrocatalysts for the oxygen evolution reaction (OER). However, according to thermodynamics, general cobalt oxide converts to the CoO2 phase under OER condition, retarding the OER kinetics. Herein, we demonstrate a simple and scalable strategy to fabricate electrodes with maintaining Fe-CoOOH phase and an IS state under the OER. The changes of phase and spin states were uncovered by combining in-situ/operando X-ray based absorption spectroscopy and Raman spectroscopy. Electrochemical reconstruction of chalcogenide treated Co foam affords a highly enlarged active surface that conferred excellent catalytic activity and stability in a large-scale water electrolyzer. Our findings are meaningful in that the calculated results were experimentally verified through the operando analyses. It also proposes a new strategy for electrode fabrication and confirms the importance of real active phases and spin states under a particular reaction condition. English Nature Publishing Group Electrode reconstruction strategy for oxygen evolution reaction: maintaining Fe-CoOOH phase with intermediate-spin state during electrolysis Article 10.1038/s41467-022-28260-5 1 Nature Communications, v.13 Nature Communications 13 Y scie scopus 000749535300014 2-s2.0-85123974390 Multidisciplinary Sciences Science & Technology - Other Topics Article WATER ELECTROLYSIS COBALT OXIDE ELECTROCATALYSTS CO3O4 CO NANOPARTICLES SUBSTITUTION GENERATION CONVERSION REDUCTION