Yusibova Gulnara, Douglin John C, Vetik Iuliia, Pozdnjakova Jekaterina, Ping Kefeng, Aruväli Jaan, Kikas Arvo, Kisand Vambola, Käärik Maike, Leis Jaan, Kaljuvee Tiit, Paaver Peeter, Oras Sven, Ciupiński Łukasz, Plocinski Tomasz, Konuhova Marina, Popov Anatoli I, Dekel Dario R, Ivaništšev Vladislav, Kongi Nadezda
Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu, Estonia.
The Wolfson Department of Chemical Engineering, Technion-Israel Institute of Technology, 3200003 Haifa, Israel.
ACS Omega. 2025 Apr 12;10(15):15280-15291. doi: 10.1021/acsomega.4c11318. eCollection 2025 Apr 22.
Metal-organic frameworks (MOFs) are promising precursors for creating metal-nitrogen-carbon (M-N-C) electrocatalysts with high performance, though maintaining their structure during pyrolysis is challenging. This study examines the transformation of a Zn-based MOF into an M-N-C electrocatalyst, focusing on the preservation of the carbon framework and the prevention of Zn aggregation during pyrolysis. A highly porous Zn-N-C electrocatalyst derived from Zn-TAL MOF (where TAL stands for the TalTech-UniTartu Alliance Laboratory) was synthesized via optimized pyrolysis, yielding notable electrocatalytic activity toward oxygen reduction reaction (ORR). Scanning electron microscopy (SEM) and X-ray diffraction spectroscopy (XRD) analyses confirmed that the carbon framework preserved its integrity and remained free of Zn metal aggregates, even at elevated temperatures. Rotating disc electrode (RDE) tests in an alkaline solution showed that the optimized Zn-N-C electrocatalyst demonstrated ORR activity on par with commercial Pt/C electrocatalysts. In an anion-exchange membrane fuel cell (AEMFC), the Zn-N-C material pyrolyzed at 1000 °C exhibited a peak power density of 553 mW cm at 60 °C. This work demonstrates that Zn-TAL MOF is an excellent precursor for forming hollow Zn-N-C structures, making it a promising high-performance Pt-free electrocatalyst for fuel cells.
金属有机框架材料（MOFs）是制备高性能金属氮碳（M-N-C）电催化剂的有前景的前驱体，尽管在热解过程中保持其结构具有挑战性。本研究考察了一种锌基金属有机框架材料向M-N-C电催化剂的转变，重点关注热解过程中碳框架的保留以及锌的聚集防止。通过优化热解合成了一种由Zn-TAL MOF（其中TAL代表塔尔图大学-塔林理工大学联盟实验室）衍生的高度多孔的Zn-N-C电催化剂，对氧还原反应（ORR）产生了显著的电催化活性。扫描电子显微镜（SEM）和X射线衍射光谱（XRD）分析证实，即使在高温下，碳框架仍保持其完整性且不存在锌金属聚集体。在碱性溶液中的旋转圆盘电极（RDE）测试表明，优化后的Zn-N-C电催化剂表现出与商业Pt/C电催化剂相当的ORR活性。在阴离子交换膜燃料电池（AEMFC）中，在1000℃热解的Zn-N-C材料在60℃时表现出553 mW cm的峰值功率密度。这项工作表明，Zn-TAL MOF是形成空心Zn-N-C结构的优异前驱体，使其成为一种有前景的用于燃料电池的高性能无铂电催化剂。
