Synthesis, properties and electrocatalytic application of g-C3N4 for oxygen electrodes of fuel cells

Abstract

A new type of metal-free oxygen electrode has been proposed. Its distinguishing feature is applying as an active layer nanodispersed graphitic carbon nitride with electrocatalytic properties controlled by synthesis conditions. Optimal conditions of thermochemical synthesis of g-C3N4 by a heat treatment of a solid mixture of melamine precursor and nitrogen-rich urea additive have been defined. The obtained layered g-C3N4 has been characterized by XRD, selected area electron diffraction, TEM and FTIR. An investigation of the electrocatalytic characteristics of oxygen electrodes has been carried out in a fuel half-cell with alkaline electrolyte. The electrochemical characteristics of the obtained g-C3N4 material with melamine-to-urea ratio 1:2 have been shown to be close to those of platinum electrodes. Electrochemical studies have shown that the obtained carbon nitride is a promising material as metal-free catalyst for oxygen electrodes of fuel cells The long-term testing of produced materials confirmed that they were stable over six months.