摘要
The development of non-platinum(Pt) oxygen reduction reaction(ORR) catalysts with high activity and low cost is of great importance for large-scale commercialization of fuel cells. By means of density functional theory(DFT) computations, we theoretically identified that two-dimensional(2D) iron-porphyrin(Fe-Pp) sheet, in which the active Fe sites are distributed regularly and separately, is an appealing candidate. The pristine Fe-Pp sheet exhibits considerably high catalytic activity and four-electron selectivity for ORR. Especially, the adsorption of ORR intermediates on Fe-Pp sheet can be significantly weakened by the addition of axial cyanogen(CN) ligand, resulting in pronouncedly enhanced ORR activity. More interestingly, the d band center of CN attached Fe-Pp(Fe-Pp-CN) sheet can be further tuned by applying the external tensile or compressive strain, leading to an enhancement or suppression of ORR catalytic performance. In particular, under a small biaxial tensile strain of 2%, the ORR activity of Fe-Pp-CN sheet is even higher than that of Pt and reaches to the top of activity volcano. Our studies open new ways to design effective non-Pt ORR catalysts for fuel cell technology.
The development of non-platinum （Pt） oxygen reduction reaction （ORR） catalysts with high activity and low cost is of great importance for large-scale commercialization of fuel cells. By means of density func- tional theory （DFT） computations, we theoretically identified that two-dimensional （2D） iron-porphyrin （Fe-Pp） sheet, in which the active Fe sites are distributed regularly and separately, is an appealing candi- date. The pristine Fe-Pp sheet exhibits considerably high catalytic activity and four-electron selectivity for ORR. Especially, the adsorption of ORR intermediates on Fe-Pp sheet can be significantly weakened by the addition of axial cyanogen （CN） ligand, resulting in pronouncedly enhanced ORR activity. More interestingly, the d band center of CN attached Fe-Pp （Fe-Pp-CN） sheet can be further tuned by applying the external tensile or compressive strain, leading to an enhancement or suppression of ORR catalytic performance. In particular, under a small biaxial tensile strain of 2%, the ORR activity of Fe-Pp-CN sheet is even higher than that of Pt and reaches to the top of activity volcano. Our studies open new ways to design effective non-Pt ORR catalysts for fuel cell technology.
基金
supported by the National Natural Science Foundation of China (21403115 and 21522305)
the Natural Science Foundation of Jiangsu Province (BK20150045)
Innovation Project in Jiangsu Province (KYZZ16-0454)
The priority academic program development of Jiangsu higher education institutions
