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Reactive oxygen species in iridium-based OER catalysts.

ABSTRACT: Tremendous effort has been devoted towards elucidating the fundamental reasons for the higher activity of hydrated amorphous Ir^III/IV oxyhydroxides (IrO _x ) in the oxygen evolution reaction (OER) in comparison with their crystalline counterpart, rutile-type IrO₂, by focusing on the metal oxidation state. Here we demonstrate that, through an analogy to photosystem II, the nature of this reactive species is not solely a property of the metal but is intimately tied to the electronic structure of oxygen. We use a combination of synchrotron-based X-ray photoemission and absorption spectroscopies, ab initio calculations, and microcalorimetry to show that holes in the O 2p states in amorphous IrO _x give rise to a weakly bound oxygen that is extremely susceptible to nucleophilic attack, reacting stoichiometrically with CO already at room temperature. As such, we expect this species to play the critical role of the electrophilic oxygen involved in O-O bond formation in the electrocatalytic OER on IrO _x . We propose that the dynamic nature of the Ir framework in amorphous IrO _x imparts the flexibility in Ir oxidation state required for the formation of this active electrophilic oxygen.

SUBMITTER: Pfeifer V

PROVIDER: S-EPMC5134683 | biostudies-literature |

REPOSITORIES: biostudies-literature

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A Bibliometric Analysis of Reactive Oxygen Species Based Nanotechnology for Cardiovascular Diseases.

Project description:Cardiovascular diseases (CVDs) continue to be the leading cause of health problems around the world. Because of its unique properties, reactive oxygen species (ROS)-based nanotechnology offers novel solutions to the diagnosis and treatment of CVDs. In order to identify and further promote the development of ROS-based nanotechnology in CVDs, we here provide a bibliometric analysis. 701 eligible articles about the ROS-based nanotechnology for CVD up to May 26th, 2022, were taken from the Web of Science Core Collection database. The VOSviewer was used to analyze annual publications, countries/institutions, funding agencies, journals and research category, and the research hotspots. From the publication of the first article in 2005 to 2021, the output and the number of citations of articles are on the rise. Based on the bibliometric analysis, we found that the current research focuses on the correlation between diagnosis (sensors and), treatment (oxidative stress, inflammation, and drug delivery) and safety (toxicity). Since 2019, research on nanomedicine and drug delivery has become a hotspot. So, more research in chemistry, materials, biology, and medicine is required to further develop and construct ROS-based nanomaterials.

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