Catalyst-Free Synthesis of Crumpled Boron and Nitrogen Co-Doped Graphite Layers with Tunable Bond Structure for Oxygen Reduction Reaction
Catalyst-Free Synthesis of Crumpled Boron and Nitrogen Co-Doped Graphite Layers with Tunable Bond Structure for Oxygen Reduction Reaction
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DOI：
10.1021/nn404927n
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发表时间：
2014-04-01
期刊：
影响因子：
17.1
通讯作者：
Sun, Gongquan
中科院分区：
文献类型：
--
作者：
Jin, Jutao;Pan, Fuping;Sun, Gongquan
基于B、C和N三元系的二维材料从电子器件到催化剂都有着广泛的应用。这些BCN纳米片内的键合排列在很大程度上决定了它们的电子结构，从而决定了它们的化学和（或）物理性质，但以方便和受控的方式操纵它们的键合结构仍然是一个挑战。最近，我们发展了一种以尿素、硼酸和聚乙二醇（PEG）为前体合成具有可调B和N键结构的BCN纳米片的方法。通过仔细选择合成条件，我们可以将BCN片的结构从B和N键合在一起的s-BCN调整为B和N均匀分散在BCN片中的h-BCN。详细的实验表明，石墨烯中B和N的最终键合结构取决于BCN纳米片中优先掺杂的N结构。当N取代面内碳原子，使其所有电子都配置在石墨烯的π电子体系中时，有利于形成B和N处于分离状态的h-BCN。相反，当氮掺杂剂被孤电子对包围时，氮取代边平面碳，有利于形成B-N结构。特别地，由于B和N之间的协同效应，富含h-BCN的化合物在碱性溶液中表现出优异的ORR性能，而s-BCN占主导地位的BCN表现出类似石墨的ORR活性，表明不同掺杂剂键排列的BCN纳米片的内在性质差异。
Two-dimensional materials based on ternary system of B, C and N are useful ranging from electric devices to catalysis. The bonding arrangement within these BCN nanosheets largely determines their electronic structure and thus chemical and (or) physical properties, yet it remains a challenge to manipulate their bond structures in a convenient and controlled manner. Recently, we developed a synthetic protocol for the synthesis of crumpled BCN nanosheets with tunable B and N bond structure using urea, boric acid and polyethylene glycol (PEG) as precursors. By carefully selecting the synthesis condition, we can tune the structure of BCN sheets from s-BCN with B and N bond together to h-BCN with B and N homogenously dispersed in BCN sheets. Detailed experiments suggest that the final bond structure of B and N in graphene depends on the preferentially doped N structure in BCN nanosheets. When N substituted the in-plane carbon atom with all its electrons configured into the pi electron system of graphene, it facilitates the formation of h-BCN with B and N in separated state. On the contrary, when nitrogen substituted the edge-plane carbon with the nitrogen dopant surrounded with the lone electron pairs, it benefits for the formation of B-N structure. Specially, the compound riched with h-BCN shows excellent ORR performance in alkaline solution due to the synergistic effect between B and N, while s-BCN dominant BCN shows graphite-like activity for ORR, suggesting the intrinsic properties differences of BCN nanosheets with different dopants bond arrangement.