【摘要】 以硝酸铁为金属离子前驱体、均苯三甲酸为有机配体,采用水热法合成了金属有机骨架MOF(Fe)催化剂,应用X射线衍射、N2吸附-脱附、透射电镜、红外光谱和热重等方法对催化剂的结构进行了表征,并采用循环伏安法测试了催化剂在碱性电解质中的氧气还原(ORR)催化性能,同时也采用旋转圆盘电极进一步研究了催化剂的ORR的动力学行为.结果表明,所制MOF(Fe)具有很好的晶型结构、大比表面积、丰富的微孔以及较高的热稳定性.且表现出很好的ORR催化活性.ORR的反应历程随电位的改变而改变:电位在–0.3到0.50 V范围内,ORR为2电子途径;随着电位从–0.50 V升至–0.95 V,ORR从2电子向4电子途径转变.另外,该催化剂在碱性电解质中也表现出较好的氧气析出(OER)催化性能,这为制备用于ORR和OER的高效非贵金属催化剂提供了新的途径.更多还原

【Abstract】 Effective bifunctional catalysts play a vital role in large-scale commercial applications of rechargea-ble lithium-air batteries. In this article, a metal-organic framework, MOF (Fe), was prepared by a hydrothermal process using ferric nitrate as the metal ion precursor and trimesic acid as an organic ligand. The structure of the MOF (Fe) was characterized by X-ray diffraction, N2 adsorp-tion-desorption, Transmission electron microscopy, Fourier transform infrared spectroscopy and Thermo-gravimetric analysis. The activity for the oxygen reduction reaction (ORR) and the kinetic behavior of the ORR using the MOF (Fe) were investigated by cyclic voltammetry and rotating disk electrode voltammetry, respectively, using an alkaline electrolyte. The characterization results showed that the MOF (Fe) was highly crystalline with abundant micropores, large specific surface area and high thermal stability. The MOF (Fe) exhibited excellent catalytic activity for the ORR. The ORR mechanism varies with the applied potentials. The ORR occurs through a two-electron path-way at potentials in the range of –0.30 to –0.50 V, but shifts to four-electron pathway with the po-tentials in the range –0.50 to –0.95 V. In addition, the MOF (Fe) shows excellent catalytic activity for the oxygen evolution reaction (OER) in an alkaline electrolyte. This work opens a new route for the development of effective non-precious metal catalysts based on MOFs for the ORR and OER.更多还原