{"title":"Grain Boundary-Derived Local Amorphization Enhances Acidic OER","authors":"Mingze Sun, Helai Huang, Xiangfu Niu, Shuyan Gong, Zhengwen Li, Jinjie Fang, Xiang Liu, Yanjun Chen, Haohong Duan, Zhongbin Zhuang, Satoshi Nagao, Yuki Aoki, Liang Zhang, Zhiqiang Niu","doi":"10.1021/acscatal.4c03746","DOIUrl":null,"url":null,"abstract":"IrO<sub><i>x</i></sub> of the amorphous phase has long been recognized to exhibit higher catalytic activity than crystalline analogues toward oxygen evolution reaction (OER) but always at the expense of reduced stability. Here, we report an ultrathin Ir surface with high-density grain boundaries (GBs), which transforms into locally stabilized amorphous IrO<sub><i>x</i></sub> by forming an Ir/IrO<sub><i>x</i></sub> interface under OER conditions. The catalyst displays a low overpotential of 263 mV at 10 mA cm<sup>–2</sup> and a mass activity (5.8 A mg<sub>Ir</sub><sup>–1</sup> at 1.53 V) of over 90-fold higher than that of commercial IrO<sub>2</sub>, along with long-term stability for over 350 h. The activity enhancement arises from the stronger binding strength of *OOH on the amorphous GBs relative to the crystalline region, thus breaking the scaling relationship between *OH and *OOH and reducing the energy barrier for the potential determining step of the OER. Proton exchange membrane water electrolysis using this catalyst achieves 2.7 A cm<sup>–2</sup> at 2 V cell voltage and operates stably at 1 A cm<sup>–2</sup> for over 200 h. The stabilization of the amorphous IrO<sub><i>x</i></sub> phase at GBs may accelerate the development of more active and robust acidic OER electrocatalysts.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":11.3000,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Catalysis ","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acscatal.4c03746","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
IrOx of the amorphous phase has long been recognized to exhibit higher catalytic activity than crystalline analogues toward oxygen evolution reaction (OER) but always at the expense of reduced stability. Here, we report an ultrathin Ir surface with high-density grain boundaries (GBs), which transforms into locally stabilized amorphous IrOx by forming an Ir/IrOx interface under OER conditions. The catalyst displays a low overpotential of 263 mV at 10 mA cm–2 and a mass activity (5.8 A mgIr–1 at 1.53 V) of over 90-fold higher than that of commercial IrO2, along with long-term stability for over 350 h. The activity enhancement arises from the stronger binding strength of *OOH on the amorphous GBs relative to the crystalline region, thus breaking the scaling relationship between *OH and *OOH and reducing the energy barrier for the potential determining step of the OER. Proton exchange membrane water electrolysis using this catalyst achieves 2.7 A cm–2 at 2 V cell voltage and operates stably at 1 A cm–2 for over 200 h. The stabilization of the amorphous IrOx phase at GBs may accelerate the development of more active and robust acidic OER electrocatalysts.
期刊介绍:
ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels.
The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.