State Key Laboratory of Engines, School of Mechanical Engineering, Tianjin University, Tianjin, 300072, P.R. China.
Key Laboratory of Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, P.R. China.
ChemSusChem. 2019 Sep 20;12(18):4165-4169. doi: 10.1002/cssc.201901668. Epub 2019 Aug 13.
As a new class of metal-nitrogen-carbon (M-N-C) material with 3 D microstructure, zeolitic imidazolate frameworks (ZIFs) are used to synthesize highly active electrocatalysts for the oxygen reduction reaction, as substitutes for commercial Pt/C in anion exchange membrane fuel cells. However, to form an effective catalyst layer (CL), the relationship between the microstructure of the ZIF-derived catalyst and the fuel cell performance must be investigated. In this work, a hierarchically porous CL based on the carbon black (CB)-controlled synthesis of a Co-based ZIF (denoted as ZIF-CB-700) is constructed to optimize the triple-phase boundary (TPB) and mass transfer. The power density at 40 °C of ZIF-CB-700 (95.4 mW cm ) as cathode catalyst is about 4 times higher than that of the catalyst synthesized in the absence of CB and is comparable to that of the commercial 60 % Pt/C catalyst (112.0 mW cm ). Both online and offline measurements suggest that the morphology and microstructure of the CL is crucial to form an active TPB region, dominating the fuel cell performance rather than only the high catalyst activity.
作为一种具有 3D 微观结构的新型金属-氮-碳 (M-N-C) 材料，沸石咪唑酯骨架 (ZIFs) 被用于合成用于阴离子交换膜燃料电池中替代商业 Pt/C 的高活性氧还原反应电催化剂。然而，为了形成有效的催化剂层 (CL)，必须研究 ZIF 衍生催化剂的微观结构与燃料电池性能之间的关系。在这项工作中，构建了基于碳黑 (CB) 控制合成的 Co 基 ZIF（记为 ZIF-CB-700）的分级多孔 CL，以优化三相界面 (TPB) 和质量传递。作为阴极催化剂的 ZIF-CB-700（在 40°C 时为 95.4 mW·cm ）的功率密度大约是在没有 CB 存在的情况下合成的催化剂的 4 倍，并且与商业 60%Pt/C 催化剂（112.0 mW·cm ）相当。在线和离线测量都表明，CL 的形态和微观结构对于形成活性 TPB 区域至关重要，这主导着燃料电池性能，而不仅仅是高催化剂活性。
