Domain-Confined Etching Strategy to Regulate Defective Sites in Carbon for High-Efficiency Electrocatalytic Oxygen Reduction
Domain-Confined Etching Strategy to Regulate Defective Sites in Carbon for High-Efficiency Electrocatalytic Oxygen Reduction
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域限制蚀刻策略调节碳缺陷位点以实现高效电催化氧还原
DOI：
10.1002/adfm.202111396
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发表时间：
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影响因子：
19
通讯作者：
Zhen He
中科院分区：
文献类型：
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作者：
Guanying Ye;Suqin Liu;Kui Huang;Siyuan Wang;Kuangmin Zhao;Weiwei Zhu;Yuke Su;Jue Wang;Zhen He
氮掺杂剂和无金属碳中本征碳缺陷（N/DC）的偶联位点在电催化氧还原反应（ORR）中具有高活性，但很难有效构建。本文报道了一种新的合成策略，利用含有金属氮基团（M - Nx）的前驱体制备N/DC富集的无金属碳。在前驱体热解过程中，M - Nxis通过卤化物介导的“诱饵和开关”机制原位转化为内源性金属氧化物（MOx），实现了氮掺杂剂周围碳基体的限域蚀刻，在最终碳产物中形成丰富的N/DC偶联位点。优化后的N/DC富集碳在0.1mKOH溶液中表现出出色的ORR活性和稳定性，半波电位为0.903 V（相对于RHE），优于大多数已报道的无金属碳催化剂。实验研究和理论计算表明，氮/直流偶联位点对ORR中间体的供电子能力得到了提高，结合能得到优化，这是ORR活性如此优异的主要原因。这种受限域内源性MOxetching策略也广泛适用于不同的含M - Nx前体和不同的卤化物介质，这为制造富含各种期望协同性能的偶联位点的金属/非金属掺杂碳材料开辟了新的可能性。
Coupling sites of nitrogen dopants and intrinsic carbon defects (N/DC) in metal‐free carbon are highly active toward electrocatalytic oxygen reduction reaction (ORR), and yet they are hard to be effectively constructed. Here, a novel synthesis strategy for fabrication of N/DC‐enriched metal‐free carbon from precursors containing metal‐nitrogen moieties (M‐Nx) is reported. During pyrolysis of the precursors, the M‐Nxis in situ converted to endogenous metal oxides (MOx) via a halide‐mediated “bait and switch” mechanism to realize a domain‐confined etching of the carbon matrix around the nitrogen dopants, forming abundant N/DC coupling sites in the final carbon products. The optimized N/DC‐enriched carbon exhibits an outstanding ORR activity and stability with a half‐wave potential of 0.903 V (versus RHE) in 0.1mKOH solution, outperforming most of the reported metal‐free carbon catalysts. Experimental investigations and theoretical calculations demonstrate an improved electron‐donating ability and optimized binding energies of the N/DC coupling sites toward the ORR intermediates, which are primarily responsible for such an excellent ORR activity. This domain‐confined endogenous MOxetching strategy is also widely applicable to different M‐Nx‐containing precursors as well as different halide mediators, which opens up new possibilities to fabricate metal/nonmetal doped carbon materials enriched with various coupling sites of desired synergistic properties.