Liu Xiaofeng, Huo Sichen, Xu Xiaoqin, Wang Xinyu, Zhang Wanyu, Chen Yanjie, Wang Cheng, Liu Xueting, Chang Haiyang, Zou Jinlong
Heilongjiang Provincial Key Laboratory of Environmental Nanotechnology and Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, China.
Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Guangdong University of Technology, Guangzhou 510006, China.
J Colloid Interface Sci. 2024 Jul 15;666:296-306. doi: 10.1016/j.jcis.2024.04.025. Epub 2024 Apr 6.
In oxygen electrocatalysis, how to rationally design low-cost catalysts with reasonable structure and long-term stability is a crucial issue. Here, an in-situ growth strategy is used to construct a shaped structure encapsulating a uniformly-dispersed Co/CoFe heterojunction in nitrogen-doped carbon nanotubes (Co/CoFe@NCNTs). Hollow CoFe layered-double-hydroxide prisms act as sacrifices for in-situ growth of Co/CoFe nanoparticles, which also catalyze the growth of bamboo-like NCNTs. Tubular structure not only accelerates the charge transfer through the interactions between Co and CoFe, but also limits the aggregation of the particles, thereby promoting the 4e oxygen reduction/evolution reactions (ORR/OER) kinetics and stabilizing the bifunctional activity. Co/CoFe@NCNTs-800 (pyrolyzed at 800 °C) shows exceptional ORR activity (half-wave potential of 0.89 V) and methanol tolerance. Meanwhile, Co/CoFe@NCNTs-800 shows a small OER overpotential of 280 mV, which increases by only 9 mV after 1000 cyclic voltammetry (CV) cycles. The outstanding bifunctionality (potential gap of 0.62 V) is ascribed to the electronic structure modulation at the Co/CoFe heterointerface. Notably, it also has a high performance as an air-cathode for rechargeable zinc-air battery, showing high power density (165 mW cm) and specific capacity (770.5 m Ah kg). This work provides a new reference for promoting the development of alloy catalysts with heterogeneous interfaces.
在氧电催化中，如何合理设计具有合理结构和长期稳定性的低成本催化剂是一个关键问题。在此，采用原位生长策略构建了一种在氮掺杂碳纳米管（Co/CoFe@NCNTs）中封装均匀分散的Co/CoFe异质结的成型结构。中空的CoFe层状双氢氧化物棱柱作为Co/CoFe纳米颗粒原位生长的牺牲剂，其还催化竹状NCNT的生长。管状结构不仅通过Co和CoFe之间的相互作用加速电荷转移，还限制了颗粒的聚集，从而促进4e氧还原/析氧反应（ORR/OER）动力学并稳定双功能活性。Co/CoFe@NCNTs-800（在800℃下热解）表现出优异的ORR活性（半波电位为0.89V）和甲醇耐受性。同时，Co/CoFe@NCNTs-800的OER过电位较小，为280mV，在1000次循环伏安（CV）循环后仅增加9mV。出色的双功能性（电位差为0.62V）归因于Co/CoFe异质界面处的电子结构调制。值得注意的是，它作为可充电锌空气电池的空气阴极也具有高性能，显示出高功率密度（165mW cm）和比容量（770.5m Ah kg）。这项工作为促进具有异质界面的合金催化剂的发展提供了新的参考。
