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High‐Performance Metal‐Free Nanosheets Array Electrocatalyst for Oxygen Evolution Reaction in Acid
Advanced Functional Materials ( IF 18.5 ) Pub Date : 2020-06-22 , DOI: 10.1002/adfm.202003000
Chaojun Lei 1 , Qiang Zheng 2 , Fanpeng Cheng 1 , Yang Hou 1 , Bin Yang 1 , Zhongjian Li 1 , Zhenhai Wen 3 , Lecheng Lei 1 , Guoliang Chai 3 , Xinliang Feng 4
Affiliation  

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.

中文翻译:

高性能无金属纳米片阵列电催化剂,用于酸中的氧释放反应

具有优异的催化活性和对酸中的氧释放反应(OER)稳定的低成本电催化剂的开发是从水分解产生氢能的主要挑战。本文报道了一种由氧官能化的电化学剥落石墨烯(OEEG)纳米片阵列组成的新型无金属电催化剂。得益于垂直排列的阵列结构并引入了氧官能团,无金属OEEG纳米片阵列在10 mA cm -2的酸性电解质中具有334 mV的低过电势,具有出色的电催化活性和对OER的稳定性。迄今为止,如此高的OER性能是所有先前报道的无金属碳基材料中最好的,甚至优于商用Ir / C催化剂(在10 mA cm时为420 mV)-2)在酸中。表征结果和电化学测量可确定OEEG中的COOH物种是酸性OER的活性位点,原子级扫描透射电子显微镜成像和电子能量损失谱进一步支持了OEEG中的COOH物种。密度泛函理论计算表明,由锯齿形和扶手椅状边缘(COOH-zig-corner)混合的双重位点的反应路径要优于单一位点的路径。
更新日期:2020-08-03
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