Understanding the roles of amorphous domains and oxygen-containing groups of nitrogen-doped carbon in oxygen reduction catalysis: toward superior activity†,Inorganic Chemistry Frontiers

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Understanding the roles of amorphous domains and oxygen-containing groups of nitrogen-doped carbon in oxygen reduction catalysis: toward superior activity†
Inorganic Chemistry Frontiers ( IF 6.1 ) Pub Date : 2019-10-25 , DOI: 10.1039/c9qi00983c
Jasper Biemolt _{1,

2,

3,

4} , Gadi Rothenberg _{1,

2,

3,

4} , Ning Yan _{1,

2,

3,

4,

5}

Affiliation

Nitrogen-doped carbons are promising candidates for replacing platinum catalysts in fuel cell electrodes. They typically contain graphitic and amorphous domains, both of which contribute to the oxygen reduction reaction (ORR) activity. Here, we aim at revealing the catalytic functions of each domain as well of the surface functional groups, and ultimately at maximizing the catalytic performance of the materials in the ORR. We develop a sequential oxidative-pyrolytic treatment to remove the amorphous domains and to alter the surface functionalities. The effectiveness of this approach is evidenced by various techniques. Our electrochemical results show a positive correlation between the ORR activity and the degree of graphitization/oxygen functional group removal. While the oxidation-induced oxygen-containing group impairs the ORR, the amorphous domains seem facilitate the 2-electron transfer ORR, lack electrical conductivity and are rich in oxygen-containing groups. The ORR activity of the optimized sample increases considerably in the alkaline electrolyte, giving a half-wave potential >0.85 V (vs. a reversible hydrogen electrode) that is comparable to that of commercial platinum on carbon.

中文翻译：

了解氮掺杂碳的无定形域和含氧基团在氧还原催化中的作用：朝着更高的活性方向转变†

氮掺杂碳有望替代燃料电池电极中的铂催化剂。它们通常包含石墨和无定形域，这两个域都有助于氧还原反应（ORR）活性。在这里，我们旨在揭示每个结构域以及表面官能团的催化功能，并最终使ORR中的材料催化性能最大化。我们开发了顺序的氧化热解处理，以删除非晶域并更改表面功能。各种技术证明了这种方法的有效性。我们的电化学结果显示，ORR活性与石墨化程度/氧官能团去除程度之间呈正相关。虽然氧化诱导的含氧基团会损害ORR，非晶域似乎促进了2-电子转移ORR，缺乏电导率并且富含含氧基团。经过优化的样品的ORR活性在碱性电解液中显着增加，从而产生的半波电势> 0.85 V（与可逆氢电极相比），可与商用铂/碳电极相媲美。

更新日期：2019-12-18

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