Single-Atomic Ruthenium Catalytic Sites on Nitrogen-Doped Graphene for Oxygen Reduction Reaction in Acidic Medium.
Single-Atomic Ruthenium Catalytic Sites on Nitrogen-Doped Graphene for Oxygen Reduction Reaction in Acidic Medium.
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DOI：
10.1021/acsnano.7b02148
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发表时间：
2017-06
期刊：
影响因子：
17.1
通讯作者：
Chenhao Zhang;Junwei Sha;H. Fei;Mingjie Liu;S. Yazdi;Jibo Zhang;Qifeng Zhong;Xiaolong Zou
中科院分区：
文献类型：
--
作者：
Chenhao Zhang;Junwei Sha;H. Fei;Mingjie Liu;S. Yazdi;Jibo Zhang;Qifeng Zhong;Xiaolong Zou
阴极氧还原反应（ORR）在燃料电池的电化学能量转换中至关重要。在这里，通过含有痕量Ru的氧化石墨烯（GO）前体的NH3气氛退火，我们合成了在氮掺杂的石墨烯上原子分散的Ru，其在酸性介质中作为ORR的电催化剂。Ru/氮掺杂的GO催化剂表现出优异的四电子ORR活性，相对于0.1 M HClO 4中的可逆氢电极（RHE），分别提供0.89和0.75 V的起始和半波电位，以及比在商业Pt/C催化剂中看到的更好的耐久性和对甲醇和一氧化碳中毒的耐受性。X射线吸收精细结构分析和像差校正的高角度环形暗场扫描透射电子显微镜进行，并表明Ru的化学结构主要由孤立的Ru原子与石墨烯衬底上的氮原子配位组成。此外，ORR机制的密度泛函理论研究表明，Ru-氧代-N4结构似乎是负责在酸性介质中的ORR催化活性。这些发现为设计有效的ORR单原子催化剂提供了途径。
The cathodic oxygen reduction reaction (ORR) is essential in the electrochemical energy conversion of fuel cells. Here, through the NH3 atmosphere annealing of a graphene oxide (GO) precursor containing trace amounts of Ru, we have synthesized atomically dispersed Ru on nitrogen-doped graphene that performs as an electrocatalyst for the ORR in acidic medium. The Ru/nitrogen-doped GO catalyst exhibits excellent four-electron ORR activity, offering onset and half-wave potentials of 0.89 and 0.75 V, respectively, vs a reversible hydrogen electrode (RHE) in 0.1 M HClO4, together with better durability and tolerance toward methanol and carbon monoxide poisoning than seen in commercial Pt/C catalysts. X-ray adsorption fine structure analysis and aberration-corrected high-angle annular dark-field scanning transmission electron microscopy are performed and indicate that the chemical structure of Ru is predominantly composed of isolated Ru atoms coordinated with nitrogen atoms on the graphene substrate. Furthermore, a density function theory study of the ORR mechanism suggests that a Ru-oxo-N4 structure appears to be responsible for the ORR catalytic activity in the acidic medium. These findings provide a route for the design of efficient ORR single-atom catalysts.