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Title: Single-Crystalline Ultrathin Co 3O 4 Nanosheets with Massive Vacancy Defects for Enhanced Electrocatalysis

The role of vacancy defects is demonstrated to be positive in various energy-related processes. However, introducing vacancy defects into single-crystalline nanostructures with given facets and studying their defect effect on electrocatalytic properties remains a great challenge. Here this paper deliberately introduces oxygen defects into single-crystalline ultrathin Co 3O 4 nanosheets with O-terminated {111} facets by mild solvothermal reduction using ethylene glycol under alkaline condition. As-prepared defect-rich Co 3O 4 nanosheets show a low overpotential of 220 mV with a small Tafel slope of 49.1 mV dec -1 for the oxygen evolution reaction (OER), which is among the best Co-based OER catalysts to date and even more active than the state-of-the-art IrO 2 catalyst. Such vacancy defects are formed by balancing with reducing environments under solvothermal conditions, but are surprisingly stable even after 1000 cycles of scanning under OER working conditions. Density functional theory plus U calculation attributes the enhanced performance to the oxygen vacancies and consequently exposed second-layered Co metal sites, which leads to the lowered OER activation energy of 2.26 eV and improved electrical conductivity. Finally, this mild solvothermal reduction concept opens a new door for the understanding and future designing of advanced defect-based electrocatalysts.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [4] ;  [2] ;  [4] ;  [2] ;  [2] ;  [3] ;  [4] ;  [2]
  1. Beijing Univ. of Chemical Technology (China); Yale Univ., West Haven, CT (United States)
  2. Beijing Univ. of Chemical Technology (China)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States)
  4. Yale Univ., West Haven, CT (United States)
Publication Date:
Report Number(s):
BNL-114373-2017-JA
Journal ID: ISSN 1614-6832; R&D Project: MA453MAEA; VT1201000
Grant/Contract Number:
SC0012704; 2016YFC0801302; 2016YFF0204402
Type:
Accepted Manuscript
Journal Name:
Advanced Energy Materials
Additional Journal Information:
Journal Volume: 8; Journal Issue: 3; Journal ID: ISSN 1614-6832
Publisher:
Wiley
Research Org:
Brookhaven National Lab. (BNL), Upton, NY (United States); Beijing Univ. of Chemical Technology (China); Yale Univ., West Haven, CT (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V); USDOE Office of Science (SC); National Natural Science Foundation of China (NNSFC)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; defect effects; electrocatalysis; oxygen vacancies; single crystals; ultrathin nanosheets
OSTI Identifier:
1395946
Alternate Identifier(s):
OSTI ID: 1392682