Bifunctional mechanism of N, P co-doped graphene for catalyzing oxygen reduction and evolution reactions

Xiong-Xiong Xue; Li-Ming Tang; Keqiu Chen; Lixin Zhang; En-Ge Wang; Yexin Feng

doi:10.1063/1.5082996

Bifunctional mechanism of N, P co-doped graphene for catalyzing oxygen reduction and evolution reactions

J Chem Phys. 2019 Mar 14;150(10):104701. doi: 10.1063/1.5082996.

Authors

Xiong-Xiong Xue¹, Li-Ming Tang¹, Keqiu Chen¹, Lixin Zhang², En-Ge Wang³, Yexin Feng¹

Affiliations

¹ School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China.
² School of Physics, Nankai University, Tianjin 300071, People's Republic of China.
³ International Center for Quantum Materials and School of Physics, Peking University, Beijing 100871, People's Republic of China.

PMID: 30876366
DOI: 10.1063/1.5082996

Abstract

The development of bifunctional catalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is highly desirable for fuel cells and rechargeable metal-air batteries. Till now, it is still challenging to achieve both efficient activities on a single commercial noble-metal catalyst. Recently, N, P co-doped graphene has shown good bifunctional evidence. However, the atomic-scale understanding of the bifunctional mechanism is still lacking. Here, we show that the N and P atoms prefer to bond with each other, forming embedded N-P clusters in graphene. The catalytic performances of the N-P clusters are sensitive to their geometries, especially the N:P ratios. The N:P ratio of ∼2 is optimal for OER, while ∼3 is optimal for ORR. Through evaluating the ORR/OER potential gaps, we found that the N-P cluster designated as N_C ²P_C ¹ shows both the high performances of ORR and OER, responsible for the unique bifunctionality in the N, P co-doped graphene.