Two-Dimensional Metal Hexahydroxybenzene Frameworks as Promising Electrocatalysts for an Oxygen Reduction Reaction
Juan Zhang, Zhenpei Zhou, Fei Wang, Yafei Li, Yu Jing
Abstract
Exploring efficient and inexpensive electrocatalysts for a cathode oxygen reduction reaction (ORR) is essential to the large-scale commercialization of fuel cells. Via first principles calculations, we systematically investigated the electrocatalytic performance of two-dimensional (2D) metal–hexahydroxybenzene frameworks (M3(C6O6)2, where M denotes Cr, Mn, Fe, Co, Ni, Cu, Ru, Rh, and Pd) for ORR. Owing to the sufficient π-electron conjugation and effective interaction between the metal and the organic linkers, the studied 2D M3(C6O6)2 are all metallic with good conductivity for electron transfer. Interestingly, the catalytic activity of M3(C6O6)2 turns out to be dependent on the interaction strength between the ORR intermediates and the metal complex (MO4) and can be modified by changing the metal atoms with different d-electron occupations. Remarkably, while 2D Mn3(C6O6)2, Fe3(C6O6)2, and Rh3(C6O6)2 show a rather good ORR activity rivaling that of Pt, 2D Co3(C6O6)2 presents a much higher onset potential than that of Pt. Our investigations provide important insights into designing and screening efficient ORR catalysts.