Comparative Study on Hydrogen Evolution Reaction Activity of Electrospun Nanofibers with Diverse Metallic Ir and IrO2 Composition Ratios
- 주제(키워드) Hydrogen evolution reaction , Nanofibers , Iridium metal , Iridium oxide , Electrospinning , DFT calculation
- 주제(기타) Chemistry, Multidisciplinary; Green & Sustainable Science & Technology; Engineering, Chemical
- 설명문(일반) [Kim, Su-jin; Jung, Hyeseung; Lee, Chongmok; Kim, Myung Hwa; Lee, Youngmi] Ewha Womans Univ, Dept Chem & Nano Sci, 52 Ewhayeodae Gil, Seoul 03760, South Korea
- 등재 SCIE, SCOPUS
- 발행기관 AMER CHEMICAL SOC
- 발행년도 2019
- URI http://www.dcollection.net/handler/ewha/000000160155
- 본문언어 영어
- Published As http://dx.doi.org/10.1021/acssuschemeng.9b00402
초록/요약
Hydrogen evolution reaction (HER) is of importance in energy conversion processes. This paper reports the facile synthesis of iridium/iridium oxide nanofibers (Ir/IrO(2)NFs) with diverse Ir and IrO2 relative composition ratios and their electrocatalytic HER activities. Highly porous Ir/IrO(2)NFs are simply synthesized via electrospinning and the following calcination at various temperatures (300-900 degrees C). Different calcination temperature alters the actual composition of Ir/IrO(2)NFs: The higher the temperature, the greater IrO2 content exists. The HER activity of Ir/IrO(2)NFs is examined in 1 M H2SO4. Ir/IrO2NF calcined at 300 degrees C exhibits the best HER activity in terms of the onset potential, overpotential generating 50 mA cm(-2), turnover frequency, Tafel slope along with the decent stability for 5 h; the HER performance of this material even exceeds that of platinum, a benchmark HER catalyst. As the IrO2 content in Ir/IrO(2)NFs increases with a higher calcination temperature, the HER activity decreases. Ir/IrO2NF calcined at 900 degrees C consists of only IrO2 and presents the worst activity. DFT calculations show that hydrogen atom adsorption on metallic Ir (not IrO2) resembles that on Pt: similar adsorption energy and adsorbate-substrate distance. Both the experimental and theoretical results clearly demonstrate that metallic Ir rather than IrO2 is a good HER catalytic platform.
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