Atomically dispersed Fe atoms anchored on S and N-codoped carbon for efficient electrochemical denitrification
Atomically dispersed Fe atoms anchored on S and N-codoped carbon for efficient electrochemical denitrification
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DOI：
10.1073/pnas.2105628118
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发表时间：
2021-08-17
影响因子：
11.1
通讯作者：
Liu, Xiang
中科院分区：
文献类型：
--
作者：
Li, Jiacheng;Li, Miao;Liu, Xiang
硝酸盐是天然水体中广泛存在的污染物，对生态安全和人类健康构成威胁。虽然通过电化学方法直接去除硝酸盐是有效的，但具有高反应性的低成本电催化剂的开发仍然具有挑战性。在本文中，制备了用于N2或NH 4+生产的双功能单原子催化剂（SAC），所述双功能单原子催化剂在N掺杂或S，N共掺杂的碳基面上具有Cu或Fe活性中心。最大硝酸盐去除能力为7，822 mg N中心点g-1 Fe，这是以前研究中最高的。在低电位（-0.57对可逆氢电极）下获得了高的氨法拉第效率（78.4%），并且在S修饰的Fe SAC上的氮选择性为100%。对S掺杂电荷转移效应的理论和实验研究表明，强的金属-载体相互作用有利于锚定单原子和提高循环性能。硫的掺杂改变了单原子中心的配位环境，产生了大量的具有较高电导率的缺陷，这对提高催化剂的活性起到了关键作用。此外，缺陷和单原子位点之间的相互作用提高了催化性能。因此，这些发现提供了一个途径，高活性SAC的设计。
Nitrate, a widespread contaminant in natural water, is a threat to ecological safety and human health. Although direct nitrate removal by electrochemical methods is efficient, the development of low-cost electrocatalysts with high reactivity remains challenging. Herein, bifunctional single-atom catalysts (SACs) were prepared with Cu or Fe active centers on an N-doped or S, N-codoped carbon basal plane for N2 or NH4+ production. The maximum nitrate removal capacity was 7,822 mg N center dot g-1 Fe, which was the highest among previous studies. A high ammonia Faradic efficiency (78.4%) was achieved at a low potential (-0.57 versus reversible hydrogen electrode), and the nitrogen selectivity was 100% on S-modified Fe SACs. Theoretical and experimental investigations of the S-doping charge-transfer effect revealed that strong metal-support interactions were beneficial for anchoring single atoms and enhancing cyclability. S-doping altered the coordination environment of single-atom centers and created numerous defects with higher conductivity, which played a key role in improving the catalyst activity. Moreover, interactions between defects and single-atom sites improved the catalytic performance. Thus, these findings offer an avenue for high active SAC design.