Elucidating the role of P on Mn‐ and N‐doped graphene catalysts in promoting oxygen reduction: Density functional theory studies

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 MnN4‐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 MnN4‐P1‐G is OH* > 2OH* > OOH* > O* > O2* > H2O*, whereas the MnN4‐P1‐G favors a four‐electron process instead of two‐electron process. The doping of P on MnN4‐P1‐G can increase the kinetic activity for the rate‐determining step as well as the Ulim for MnN4‐P1‐G significantly increases from 0.38 to 0.45 V compared with MnN4‐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 MnN4 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.

Keywords

• MnN4 graphene
• oxygen reduction reaction
• P doping