Nitrogen and sulfur codoped graphite foam as a self-supported metal-free electrocatalytic electrode for water oxidation

The oxidation of water to produce oxygen gas is related to a variety of energy storage systems. Thus, the development of efficient, cheap, durable, and scalable electrocatalysts for oxygen evolution reaction (OER) is of great importance. Here, a high-performance OER catalyst, nitrogen and sulfur codoped graphite foam (NSGF) is reported. This NSGF is prepared from commercial graphite foil and directly applied as an electrocatalytic electrode without using a current collector and a polymeric binder. It exhibits an extremely low overpotential of 0.380 V to reach a current density of 10 mA cm^-2 and shows fast kinetics with a small Tafel slope of 96 mV dec^-1 in 0.1 m KOH. This electrocatalytic performance is superior or comparable to those of previously reported metal-free OER catalysts. Nitrogen and sulfur codoped graphite foam (NSGF), prepared by oxidizing and doping a commercial graphite foil can be applied as a self-supported electrode without a current collector and polymeric binder for oxygen evolution reaction (OER). Its electrocatalytic performance is superior or comparable to those of reported metal-free OER catalysts.