Strongly Coupled 3D Hybrids of N-doped Porous Carbon Nanosheet/CoNi Alloy-Encapsulated Carbon Nanotubes for Enhanced Electrocatalysis
Strongly Coupled 3D Hybrids of N-doped Porous Carbon Nanosheet/CoNi Alloy-Encapsulated Carbon Nanotubes for Enhanced Electrocatalysis
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DOI：
10.1002/smll.201502297
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发表时间：
2015-11-25
期刊：
影响因子：
13.3
通讯作者：
Chen, Junhong
中科院分区：
文献类型：
--
作者：
Hou, Yang;Cui, Shumao;Chen, Junhong
设计并构建了一种新颖的三维纳米结构，该结构包括原位形成的N掺杂的CoNi合金封装的碳纳米管（CoNi-NCNT），该碳纳米管生长在N掺杂的多孔碳纳米片（NPCN）上，用于氧还原反应（ORR）和析氧反应（OER）。当作为ORR的电催化剂进行评价时，与商业Pt/C催化剂相比，该混合物显示出高效的催化活性、高选择性、上级耐久性和对甲醇渗透的强耐受性。这种良好的氧还原反应性能与大多数先前报道的结果相当，并且发现协同效应提高了催化性能。此外，所构建的杂化物表现出优异的ORR活性，在1.59 V下的电流密度为10 mA cm（-2），起始电位为1.57 V，甚至超过了最先进的Ir/C催化剂在碱性介质中。电化学性能的提高可以归因于混合物中独特的形貌和缺陷结构、高孔隙率、良好的导电网络以及CoNi-NCNT和NPCN的强烈相互作用。这些结果表明，有效的纳米碳电催化剂的发展，以取代商业贵金属催化剂直接用于燃料电池和水裂解装置的可能性。
A novel 3D nanoarchitecture comprising in situ-formed N-doped CoNi alloy-encapsulated carbon nanotubes (CoNi-NCNTs) grown on N-doped porous carbon nanosheets (NPCNs) is designed and constructed for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). When evaluated as an electrocatalyst for ORR, the hybrid shows efficient catalytic activity, high selectivity, superior durability, and strong tolerance against methanol crossover compared with the commercial Pt/C catalyst. Such good oxygen reduction reaction performance is comparable to most of the previously reported results and the synergistic effect is found to boost the catalytic performance. Moreover, the constructed hybrid exhibits an excellent ORR activity with a current density of 10 mA cm(-2) at 1.59 V and an onset potential of 1.57 V, even beyond the state-of-the-art Ir/C catalyst in alkaline media. The enhancement in electrochemical performance can be attributed to the unique morphology and defect structures, high porosity, good conductive networks, and strongly interacting CoNi-NCNT and NPCN in the hybrid. These results suggest the possibility for the development of effective nanocarbon electrocatalysts to replace commercial noble metal catalysts for direct use in fuel cells and water splitting devices.