Hong Nhan Nong, Lorenz J. Falling, Arno Bergmann, Malte Klingenhof, Hoang Phi Tran, Camillo Spöri, Rik Mom, Janis Timoshenko, Guido Zichittella, Axel Knop-Gericke, Simone Piccinin, Javier Pérez-Ramírez, Beatriz Roldan Cuenya, Robert Schlögl, Peter Strasser, Detre Teschner, Travis E. Jones
{"title":"Key role of chemistry versus bias in electrocatalytic oxygen evolution","authors":"Hong Nhan Nong, Lorenz J. Falling, Arno Bergmann, Malte Klingenhof, Hoang Phi Tran, Camillo Spöri, Rik Mom, Janis Timoshenko, Guido Zichittella, Axel Knop-Gericke, Simone Piccinin, Javier Pérez-Ramírez, Beatriz Roldan Cuenya, Robert Schlögl, Peter Strasser, Detre Teschner, Travis E. Jones","doi":"10.1038/s41586-020-2908-2","DOIUrl":null,"url":null,"abstract":"The oxygen evolution reaction has an important role in many alternative-energy schemes because it supplies the protons and electrons required for converting renewable electricity into chemical fuels1–3. Electrocatalysts accelerate the reaction by facilitating the required electron transfer4, as well as the formation and rupture of chemical bonds5. This involvement in fundamentally different processes results in complex electrochemical kinetics that can be challenging to understand and control, and that typically depends exponentially on overpotential1,2,6,7. Such behaviour emerges when the applied bias drives the reaction in line with the phenomenological Butler–Volmer theory, which focuses on electron transfer8, enabling the use of Tafel analysis to gain mechanistic insight under quasi-equilibrium9–11 or steady-state assumptions12. However, the charging of catalyst surfaces under bias also affects bond formation and rupture13–15, the effect of which on the electrocatalytic rate is not accounted for by the phenomenological Tafel analysis8 and is often unknown. Here we report pulse voltammetry and operando X-ray absorption spectroscopy measurements on iridium oxide to show that the applied bias does not act directly on the reaction coordinate, but affects the electrocatalytically generated current through charge accumulation in the catalyst. We find that the activation free energy decreases linearly with the amount of oxidative charge stored, and show that this relationship underlies electrocatalytic performance and can be evaluated using measurement and computation. We anticipate that these findings and our methodology will help to better understand other electrocatalytic materials and design systems with improved performance. Spectroscopic studies and theoretical calculations of the electrocatalytic oxygen evolution reaction establish that reaction rates depend on the amount of charge stored in the electrocatalyst, and not on the applied potential.","PeriodicalId":18787,"journal":{"name":"Nature","volume":null,"pages":null},"PeriodicalIF":50.5000,"publicationDate":"2020-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1038/s41586-020-2908-2","citationCount":"266","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nature","FirstCategoryId":"103","ListUrlMain":"https://www.nature.com/articles/s41586-020-2908-2","RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MULTIDISCIPLINARY SCIENCES","Score":null,"Total":0}
引用次数: 266
Abstract
The oxygen evolution reaction has an important role in many alternative-energy schemes because it supplies the protons and electrons required for converting renewable electricity into chemical fuels1–3. Electrocatalysts accelerate the reaction by facilitating the required electron transfer4, as well as the formation and rupture of chemical bonds5. This involvement in fundamentally different processes results in complex electrochemical kinetics that can be challenging to understand and control, and that typically depends exponentially on overpotential1,2,6,7. Such behaviour emerges when the applied bias drives the reaction in line with the phenomenological Butler–Volmer theory, which focuses on electron transfer8, enabling the use of Tafel analysis to gain mechanistic insight under quasi-equilibrium9–11 or steady-state assumptions12. However, the charging of catalyst surfaces under bias also affects bond formation and rupture13–15, the effect of which on the electrocatalytic rate is not accounted for by the phenomenological Tafel analysis8 and is often unknown. Here we report pulse voltammetry and operando X-ray absorption spectroscopy measurements on iridium oxide to show that the applied bias does not act directly on the reaction coordinate, but affects the electrocatalytically generated current through charge accumulation in the catalyst. We find that the activation free energy decreases linearly with the amount of oxidative charge stored, and show that this relationship underlies electrocatalytic performance and can be evaluated using measurement and computation. We anticipate that these findings and our methodology will help to better understand other electrocatalytic materials and design systems with improved performance. Spectroscopic studies and theoretical calculations of the electrocatalytic oxygen evolution reaction establish that reaction rates depend on the amount of charge stored in the electrocatalyst, and not on the applied potential.
期刊介绍:
Nature is a prestigious international journal that publishes peer-reviewed research in various scientific and technological fields. The selection of articles is based on criteria such as originality, importance, interdisciplinary relevance, timeliness, accessibility, elegance, and surprising conclusions. In addition to showcasing significant scientific advances, Nature delivers rapid, authoritative, insightful news, and interpretation of current and upcoming trends impacting science, scientists, and the broader public. The journal serves a dual purpose: firstly, to promptly share noteworthy scientific advances and foster discussions among scientists, and secondly, to ensure the swift dissemination of scientific results globally, emphasizing their significance for knowledge, culture, and daily life.