电催化剂
过电位
材料科学
析氧
分解水
催化作用
石墨烯
扫描透射电子显微镜
电解质
纳米技术
化学工程
无机化学
透射电子显微镜
电化学
电极
有机化学
物理化学
化学
工程类
光催化
作者
Chaojun Lei,Qiang Zheng,F. T. Cheng,Yang Hou,Bin Yang,Zhongjian Li,Zhenhai Wen,Lecheng Lei,Guoliang Chai,Xinliang Feng
标识
DOI:10.1002/adfm.202003000
摘要
Abstract Development of low cost electrocatalysts with outstanding catalytic activity and stability for oxygen evolution reaction (OER) in acid is a major challenge to produce hydrogen energy from water splitting. Herein, a novel metal‐free electrocatalyst consisting of a oxygen‐functionalized electrochemically exfoliated graphene (OEEG) nanosheets array is reported. Benefitting from a vertically aligned arrays structure and introducing oxygen functional groups, the metal‐free OEEG nanosheets array exhibits superior electrocatalytic activity and stability toward OER with a low overpotential of 334 mV at 10 mA cm −2 in acidic electrolyte. Such a high OER performance is thus far the best among all previously reported metal‐free carbon‐based materials, and even superior to commercial Ir/C catalysts (420 mV at 10 mA cm −2 ) in acid. Characterization results and electrochemical measurements identify the COOH species in the OEEG acting as active sites for acidic OER, which is further supported by atomic‐scale scanning transmission electron microscopy imaging and electron energy‐loss spectroscopy. Density functional theory calculations reveal that the reaction pathway of dual sites that is mixed by zigzag and armchair edges (COOH‐zig‐corner) is better than the pathway of single site.
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