Photoelectron Spectroscopy at the Graphene–Liquid Interface Reveals the Electronic Structure of an Electrodeposited Cobalt/Graphene Electrocatalyst |
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| Authors: | Dr Juan J Velasco‐Velez Verena Pfeifer Dr Michael Hävecker Dr Robert S Weatherup Dr Rosa Arrigo Prof Dr Cheng‐Hao Chuang Eugen Stotz Gisela Weinberg Prof Dr Miquel Salmeron Prof Dr Robert Schlögl Dr Axel Knop‐Gericke |
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| Institution: | 1. Max Planck Institute for Chemical Energy Conversion, Mülheim 45470 (Germany);2. Fritz‐Haber‐Institut der Max‐Planck‐Gesellschaft, Berlin 14195 (Germany);3. Helmholtz‐Center Berlin for Materials and Energy, BESSY?II, Berlin 12489 (Germany);4. Engineering Department, University of Cambridge, Cambridge CB3 0FA (UK);5. Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley 94720 (USA);6. Diamond Light Source, Oxfordshire OX11 0QX (UK);7. Department of Physics, Tamkang University, Tamsui 251 (Taiwan) |
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| Abstract: | Electrochemically grown cobalt on graphene exhibits exceptional performance as a catalyst for the oxygen evolution reaction (OER) and provides the possibility of controlling the morphology and the chemical properties during deposition. However, the detailed atomic structure of this hybrid material is not well understood. To elucidate the Co/graphene electronic structure, we have developed a flow cell closed by a graphene membrane that provides electronic and chemical information on the active surfaces under atmospheric pressure and in the presence of liquids by means of X‐ray photoelectron spectroscopy (XPS). We found that cobalt is anchored on graphene via carbonyl‐like species, namely Co(CO)x, promoting the reduction of Co3+ to Co2+, which is believed to be the active site of the catalyst. |
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| Keywords: | electrocatalysis electrodeposition graphene/cobalt photoelectron spectroscopy X‐ray absorption spectroscopy |
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