Bimetallic AgNi nanoparticles anchored onto MOF-derived nitrogen-doped carbon nanostrips for efficient hydrogen evolution

Hydrogen energy has long been recognized as a clean alternative to conventional fossil fuels,which can be applied in a wide range of transportation and power generation applications.The rational design and engineering of high-performance and robust catalysts for hydrogen evolution reaction(HER)shows not a great significance but a challenge for efficient electrochemical water splitting.Herein,a new type of Nibased Ni-ABDC precursor has been obtained,which leads to the formation of N-doped porous carbon nanomaterials uniformly coated with wellproportioned bimetallic AgNi alloys via a stepwise strategy.To their credit,all samples of AgNi/NC-X are structurally calcined from the pristine AgNi-ABDC-X by tuning the different concentration of AgNO3,which means all of them maintain the vermicelli-like morphology compared with Ni-ABDC.The series of AgNi/NC-X materials can be regarded as effective electrocatalysts for HER both in acidic and alkaline media,but an acid-leaching phenomenon is observed.Among them,the as-prepared AgNi/NC-2 exhibits a low overpotential of 103 mV at the current density of 10 mA cm^(-2)and decent durability with a high retention rate of 90.9%after 10 h in 1.0 mol L^(-1)KOH electrolyte.The compelling HER properties of AgNi/NC-2 can be attributed to the synergistic effect between the hierarchical carbon materials,partial N-doping and abundant AgNi alloys.Meanwhile,this study provides a practicable method for the development of efficient HER electrocatalysts for energy applications,which can be conveniently prepared through the reasonable introduction of active components in the crystalline inorganic-organic precursors.©2021 Institute of Process Engineering,Chinese Academy of Sciences.Publishing services by Elsevier B.V.on behalf of KeAi Communications Co.,Ltd.This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).

碳纳米管锚定在中空碳上用于高效氧还原反应

设计和制备用于高效氧还原反应(ORR)的非贵金属基电催化剂对于清洁能源转换装置的开发至关重要,但又极具挑战性.在本工作中,我们通过热解双金属前驱体ZIF-Zn/Co,成功制备了一种新型的分级中空碳纳米复合材料HNCT-CNT.该材料富含Co-Nx位点以及原位形成的多壁碳纳米管.理论和实验表明, HNCT-CNT使ORR中间体的活化能垒降低,因而表现出了优异的ORR性能.最佳催化剂表现出较正的半波电位为0.85 V,极限电流密度高达6.36 mA cm^(-2), Tafel斜率为58.2 mV dec^(-1),且结构稳定性良好.此外,基于HNCT-CNT组装的锌空气电池还显示出1.49 V的开路电压和116.56 mW cm^(-2)的功率密度.综上,这种无机物模板法为制备金属有机框架化合物衍生的非贵金属基碳纳米电催化剂用于高效的电化学能源领域提供了一种新的方法.

金属有机框架衍生的三维有序多孔碳纳米材料用于高效碱性锌空气电池

设计和制备高催化活性和高稳定性的非贵金属催化剂对金属-空气电池和燃料电池研究具有重要意义.本文中,我们通过二氧化硅模板法和碳纳米管(CNT)生长对金属有机框架ZIF-8进行碳化,合成了一种分级三维有序多孔碳纳米材料.进一步通过添加铁源,高温热解获得的多孔mFeNC-CNT具有精细的Fe基纳米颗粒以及原子分散Fe-Nx位点.三维多孔结构降低了电荷传输阻力,使得铁、氮共掺杂碳表现出与商业Pt/C相当的氧还原反应(ORR)性能.同时,在尿素催化下得到的交织CNT在电化学过程中进一步缩短了离子和电子的扩散途径.实验和理论计算结果表明,优化后的mFeNC-CNT在锌空气电池上表现出较高的ORR活性.综上,这项工作为用于能量存储、转换和传输应用的高性能非贵金属基电催化剂的合理设计和简便合成提供了一种有前景的策略.