Elucidating the role of P on Mn‐ and N‐doped graphene catalysts in promoting oxygen reduction: Density functional theory studies
Yaqiang Li, Penghui Ren, Xiangyu Lu, Jinqiu Zhang, Peixia Yang, Xiaoxuan Yang, Guangzhao Wang, Anmin Liu, Gang Wu, Maozhong An
Abstract
Abstract The non‐noble Mn coordinated N, P co‐doping graphene materials were investigated theoretically in this work based on density functional theory calculation. The electronic structure is effectively tuned after the introduction of P heteroatom. The moderate d band center and density of states at Fermi energy of MnN 4 ‐P1‐G indicate that it is of modest adsorption ability for these O‐containing intermediates. The rank of adsorption energies of O‐containing intermediates for MnN 4 ‐P1‐G is OH* > 2OH* > OOH* > O* > O 2 * > H 2 O*, whereas the MnN 4 ‐P1‐G favors a four‐electron process instead of two‐electron process. The doping of P on MnN 4 ‐P1‐G can increase the kinetic activity for the rate‐determining step as well as the U lim for MnN 4 ‐P1‐G significantly increases from 0.38 to 0.45 V compared with MnN 4 ‐G. The spin density and magnetic moments of Mn are effectively tuned by d, p hybridization to lower the adsorption energy of OH intermediates (rate‐determining step [RDS]) so as to improve the catalytic activity. It is concluded that the P‐doped MnN 4 catalysts with excellent oxygen reduction reaction activity can be obtained and this study can provide theoretical guidance for the rational design of high‐performance Mn‐based carbon materials catalysts.