Etching-directed nitrogen doping strategy to construct efficient defective sites in carbon for electrocatalytic oxygen reduction
Etching-directed nitrogen doping strategy to construct efficient defective sites in carbon for electrocatalytic oxygen reduction
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DOI：
10.1016/j.jpowsour.2022.232122
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发表时间：
2022-11
影响因子：
9.2
通讯作者：
Guanying Ye;Ting Zeng;Siyuan Wang;Suqin Liu;Zhen He
中科院分区：
文献类型：
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作者：
Guanying Ye;Ting Zeng;Siyuan Wang;Suqin Liu;Zhen He
在N掺杂碳中构建本征碳缺陷与N掺杂剂的协同偶联位点，对提高无金属碳基材料对氧还原反应（ORR）的催化活性具有重要意义。然而，现有策略的碳缺陷构建和N掺杂通常是独立的过程，导致碳材料中的本征碳缺陷和N掺杂的排列是随机的（即很难形成偶联位点）。本文提出了一种用于构建碳缺陷/N掺杂偶联位点的定向氮掺杂策略，即在N掺杂碳合成过程中新产生的本征碳缺陷处定向掺杂氮。所制备的富含这些偶联位点的n掺杂碳催化剂具有显著的ORR催化活性，ORR半波电位相对于RHE为0.891 V，并且具有优异的长期耐久性（0.6 V相对于RHE，在15,000 s后电流损失3%）。实验表征和理论计算揭示了偶联位点的形成机理及其对ORR高催化活性的来源。这种蚀刻定向氮掺杂策略对于在不同前驱体衍生的碳基材料中可控构建活性位点用于电化学储能和转换应用具有很大的通用性。
Construction of synergistic coupling sites of intrinsic carbon defects and N dopants in N-doped carbon is of great significance to improve the catalytic activities of metal-free carbon-based materials toward oxygen reduction reaction (ORR). However, the carbon-defect construction and N doping by existing strategies are usually independent processes, resulting in a random arrangement of the intrinsic carbon defects and N-dopants (i.e., hardly forming the coupling sites) in the resultant carbon materials. Herein, an etching-directed nitrogen doping strategy for constructing carbon defect/N dopant coupling sites is developed, in which nitrogen is directionally doped at the freshly created intrinsic carbon defects during the synthesis of N-doped carbon. The as-prepared N-doped carbon catalyst enriched with such coupling sites renders a remarkable ORR catalytic activity with an ORR half-wave potential of 0.891 V vs. RHE and an excellent long-term durability (3% current loss after 15,000 s at 0.6 V vs. RHE). Experimental characterizations and theoretical calculations reveal the formation mechanism of the coupling sites as well as the origin of their high catalytic activities toward ORR. This etching-directed nitrogen doping strategy shows great universality for the controllable construction of active sites in carbon-based materials derived from different precursors for electrochemical energy storage and conversion applications.