Wang Yen-Zen, Hsieh Tar-Hwa, Huang Yu-Chang, Ho Ko-Shan
Department of Chemical and Materials Engineering, National Yu-Lin University of Science & Technology, 123, Sec. 3, University Rd., Yun-Lin 64301, Taiwan.
Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan.
Polymers (Basel). 2023 Feb 11;15(4):915. doi: 10.3390/polym15040915.
In order to yield more Co(II), 2,6-diaminopyridine (DAP) was polymerized with 4,4-methylene diphenyl diisocyanates (MDI) in the presence of Co(II) to obtain a Co-complexed polyurea (Co-PUr). The obtained Co-PUr was calcined to become Co, N-doped carbon (Co-N-C) as the cathode catalyst of an anion exchange membrane fuel cell (AEMFC). High-resolution transmission electron microscopy (HR-TEM) of Co-N-C indicated many Co-Nx (Co covalent bonding with several nitrogen) units in the Co-N-C matrix. X-ray diffraction patterns showed that carbon and cobalt crystallized in the Co-N-C catalysts. The Raman spectra showed that the carbon matrix of Co-N-C became ordered with increased calcination temperature. The surface area (dominated by micropores) of Co-N-Cs also increased with the calcination temperature. The non-precious Co-N-C demonstrated comparable electrochemical properties (oxygen reduction reaction: ORR) to commercial precious Pt/C, such as high on-set and half-wave voltages, high limited reduction current density, and lower Tafel slope. The number of electrons transferred in the cathode was close to four, indicating complete ORR. The max. power density (P) of the single cell with the Co-N-C cathode catalyst demonstrated a high value of 227.7 mWcm.
为了生成更多的钴（II），在钴（II）存在的情况下，将2,6 - 二氨基吡啶（DAP）与4,4'-亚甲基二苯基二异氰酸酯（MDI）聚合，以获得钴络合聚脲（Co-PUr）。将所得的Co-PUr煅烧以形成作为阴离子交换膜燃料电池（AEMFC）阴极催化剂的钴、氮掺杂碳（Co-N-C）。Co-N-C的高分辨率透射电子显微镜（HR-TEM）表明在Co-N-C基质中有许多Co-Nx（钴与几个氮共价键合）单元。X射线衍射图谱表明碳和钴在Co-N-C催化剂中结晶。拉曼光谱表明Co-N-C的碳基质随着煅烧温度的升高而变得有序。Co-N-Cs的表面积（以微孔为主）也随着煅烧温度的升高而增加。非贵金属Co-N-C表现出与商业贵金属Pt/C相当的电化学性能（氧还原反应：ORR），如高起始和半波电压、高极限还原电流密度以及较低的塔菲尔斜率。阴极中转移的电子数接近四个，表明ORR完全。具有Co-N-C阴极催化剂的单电池的最大功率密度（P）显示出227.7 mW/cm²的高值。
