Hu Yating, Li Changjian, Xi Shibo, Deng Zeyu, Liu Ximeng, Cheetham Anthony K, Wang John
Department of Materials Science and Engineering National University of Singapore 9 Engineering Drive 1 Singapore 117574 Singapore.
Function Hub Hong Kong University of Science and Technology (Guangzhou) S&T Building, Nansha IT Park Guangzhou 511458 China.
Adv Sci (Weinh). 2021 Jan 4;8(4):2003212. doi: 10.1002/advs.202003212. eCollection 2021 Feb.
Although metal-organic frameworks (MOFs) are being widely used to derive functional nanomaterials through pyrolysis, the actual mechanisms involved remain unclear. In the limited studies to date, elemental metallic species are found to be the initial products, which limits the variety of MOF-derived nanomaterials. Here, the pyrolysis of a manganese triazolate MOF is examined carefully in terms of phase transformation, reaction pathways, and morphology evolution in different conditions. Surprisingly, the formation of metal is not detected when manganese triazolate is pyrolyzed in an oxygen-free environment. Instead, a direct transformation into nanoparticles of manganese nitride, MnN embedded in N-doped graphitic carbon took place. The electrically conductive MnN nanoparticles show much better air stability than bulk samples and exhibit promising electrocatalytic performance for the oxygen reduction reaction. The findings on pyrolysis mechanisms expand the potential of MOF as a precursor to derive more functional nanomaterials.
尽管金属有机框架材料（MOFs）正被广泛用于通过热解来制备功能纳米材料，但其实际涉及的机制仍不清楚。在迄今为止有限的研究中，发现元素金属物种是初始产物，这限制了MOF衍生纳米材料的种类。在此，针对不同条件下的相变、反应途径和形态演变，仔细研究了一种三唑锰MOF的热解过程。令人惊讶的是，当三唑锰在无氧环境中热解时，未检测到金属的形成。相反，发生了直接转变为嵌入氮掺杂石墨碳中的氮化锰（MnN）纳米颗粒的过程。导电的MnN纳米颗粒表现出比块状样品更好的空气稳定性，并在氧还原反应中展现出有前景的电催化性能。关于热解机制的这些发现扩展了MOF作为前驱体衍生更多功能纳米材料的潜力。
