From Graphene Oxide to N-Doped Graphene: Understanding the Doping Process

Abstract

N-doped carbon nanostructures have gained attention as an alternative electrocatalyst for diverse reactions. They are making attractive the scalable methods to achieve enough material. However, optimizing the appropriate nitrogen species in the N-doped graphitic electrocatalysts is critical. Here, the N-doping process to obtain N-doped graphene starting from graphene oxide (GO) as the precursor to contributing toward this goal is explored. The role of doping temperatures and doping times on nitrogen incorporation into the graphene sheets, the subsequent desorption, and the influence of the oxygen (O) species from the GO during the N-doping process are analyzed. The experimental evidence is combined with first-principles density functional theory calculations to understand key characteristics of the N-doping process, particularly emphasizing the proportion of N species obtained. Finally, the critical sensitivity to N species proportions present in the electrocatalysts is illustrated by evaluating the activity and selectivity for the oxygen reduction reaction with a set of three different samples designed.