Highly Stable, Low-Cost Metal-Free Oxygen Reduction Reaction Electrocatalyst Based on Nitrogen-Doped Pseudo-Graphite

Abstract

There have been many advancements in the search for an oxygen reduction reaction (ORR) catalyst that exhibits strong performance and exceptional durability using low-cost materials. Although recent advancements have focused on matching or surpassing the ORR performance of Pt/C, exploring ways to improve the durability of electrocatalysts on longer time scales has not been adequately addressed. In this work, a high-performance and stable ORR electrocatalyst was produced using a simple nitrogen-doping protocol on GUITAR (pseudo-Graphite from the University of Idaho Thermolyzed Asphalt Reaction)-coated Ketjen black (N′-GUITAR/KB). X-ray photoelectron spectroscopy indicates selective doping of pyridinic and pyrrolic moieties (total N abundance of 0.9%). Voltammetric experiments in O2-saturated 0.1 M KOH indicate that the electrocatalyst is exceptionally stable and one of the highest performers regarding overvoltage and current density. The system maintained its electrocatalytic performance throughout the Department of Energy stress protocol, which consists of 30,000 convective cyclic voltammetry cycles in O2-saturated 0.1 M KOH. This remarkable stability, along with the low-cost synthesis, represents an important milestone in overcoming the challenges that prevent wide-scale adoption of fuel cell technology.