Quantifying Graphitic Edge Exposure in Graphene-Based Materials and Its Role in Oxygen Reduction Reactions

Abstract

Oxygen electrochemistry is at the core of several emerging energy conversion technologies. The role of carbon nanostructures in the electrocatalysis of the oxygen reduction reaction is not well understood. Herein we report an investigation of the role of graphitic edges in oxygen electrochemistry. A new synthetic method was used to create all-carbon model electrode materials with controlled morphology. Electron microscopy results show that synthesized materials possess a high density of graphitic edges. Electrochemical intercalation experiments however indicate that the density of electroactive edges does not correlate positively with microscopy results. The materials were then characterized as electrodes for the oxygen reduction reaction in alkaline media. Results suggest that electrochemical determinations of edge and defect density more accurately predicts electrocatalytic activity thus suggesting that in situ characterization techniques are needed to understand the carbon/electrolyte interface.

Tailored synthesis of active reduced graphene oxides from waste graphite: Structural defects and pollutant-dependent reactive radicals in aqueous organics decontamination

“…Metal-based catalysts have been proved to be highly reactive in catalytic ozonation, however, the deactivation by metal leaching cannot be fully avoided [10]. To construct a sustainable future, the emerging carbon-based materials, especially nanocarbons, have been developed as the state-of-the-art alternatives to the metal-based materials for environmental catalysis due to their exceptional physico-chemical properties, no heavy metal leaching and environmental friendliness [5,[11][12][13][14][15]. Studies revealed that graphene oxide (GO) and reduced graphene oxide (rGO) materials demonstrated excellent catalytic ozonation activities in destruction of POPs [8,16].…”

Untangling Cooperative Effects of Pyridinic and Graphitic Nitrogen Sites at Metal‐Free N‐Doped Carbon Electrocatalysts for the Oxygen Reduction Reaction

“…The nitrogen-free carbon electrode shows poor activity (see Figure S5), as expected of an undoped carbon, with Eon = 0.65 VRHE comparable to that of undoped carbon electrodes as reported in previous studies. [25,40] The a-C NH3 900 sample also displays the highest current density in the region < 0.5 VRHE associated with mass-transport; the current density |j| at 0.1 VRHE is close to the theoretical Levich current of ca. 4.2 mA cm -2 for a 4e-reduction of O2 at 900 rpm.…”

A Roadmap for Achieving Sustainable Energy Conversion and Storage: Graphene-Based Composites Used Both as an Electrocatalyst for Oxygen Reduction Reactions and an Electrode Material for a Supercapacitor

“…Colavita et al revealed that it is feasible to tune ORR activity and obtain higher onset potentials by modifying the carbon matrix exclusively without heteroatom dopants. Catalytic activity is closely associated with carbon matrix structure that has a possibility to have the effect of chemical doping simulated or screened [53].…”