Structural stability and O2 dissociation on nitrogen-doped graphene with transition metal atoms embedded: A first-principles study

Mingye Yang,Tingjun Hou,Lu Wang,Min Li,Youyong Li

doi:10.1063/1.4922841

Abstract

By using first-principles calculations, we investigate the structural stability of nitrogen-doped (N-doped) graphene with graphitic-N, pyridinic-N and pyrrolic-N, and the transition metal (TM) atoms embedded into N-doped graphene. The structures and energetics of TM atoms from Sc to Ni embedded into N-doped graphene are studied. The TM atoms at N4V 2 forming a 4N-centered structure shows the strongest binding and the binding energies are more than 7 eV. Finally, we investigate the catalytic performance of N-doped graphene with and without TM embedding for O2 dissociation, which is a fundamental reaction in fuel cells. Compared to the pyridinic-N, the graphitic-N is more favorable to dissociate O2 molecules with a relatively low reaction barrier of 1.15 eV. However, the catalytic performance on pyridinic-N doped structure can be greatly improved by embedding TM atoms, and the energy barrier can be reduced to 0.61 eV with V atom embedded. Our results provide the stable structure of N-doped graphene and its potential applications in the oxygen reduction reactions.

Highlights

INTRODUCTIONN-graphene varies with different experiments and related to the experimental conditions (catalyst, precursors, etc.).[19,20,21]
Graphene is a two-dimensional nanomaterial with sp2-bonded carbon atoms packed in a honey comb lattice
We investigate the structural stability of graphene doped by different types of N including graphitic N, pyridinic N and pyrrolic N

Summary

INTRODUCTION

N-graphene varies with different experiments and related to the experimental conditions (catalyst, precursors, etc.).[19,20,21]. Graphene with the impurity of transition metal (TM) is expected to have potential applications in spintronic devices and chemical catalyst, but the binding energies for TM in pristine graphene is weak and it prefers clustering. We study the structures, energetics and O2 dissociation on different types of Ndoped graphene with and without TM-embedding. We illustrate the structural stability for different types of N-doping in graphene and the energetics for TM-embedded N-doped graphene. N-doped graphene was suggested to be used as electrocatalyst for ORR,[12,29,30] and here we show which type of N dominates the catalytic reaction and how the embedded TM atoms further enhance the catalytic performance. We calculated the reaction barrier by the energy of reactant minus the energy of transition state and the formation enthalpy by the energy of reactant minus the energy of product

Structural stability of N-doped graphene

TM embedded into different types of N-doped graphene

CONCLUSIONS