Flexible self-supporting metal-free N-doped graphene membrane as an electrocatalyst for oxygen evolution reaction

The exploration of highly active and low-cost non-noble metal or even metal-free electrocatalysts for oxygen evolution reaction (OER) prove much vital for the development of advanced energy storage and conversion systems. Metal-free carbon-based electrocatalysts attract much attention due to their rich resource and low expenditure, but their practical application still remains as a huge challenge. In this work, flexible self-supporting metal-free N-doped graphene (NG) membrane is prepared by a blade coating assisted hydrothermal method. The morphology, structure and other physicochemical properties of this NG membrane are systematically characterized and analyzed. The results reveal that the resultant NG membrane shows unique flexible self-supporting architecture and achieves successful N doping, which guarantees excellent flexibility and tensile strength, and strengthens the intrinsic catalytic activity, electrical conductivity and hydrophilicity of NG membrane. As a consequence, when directly used as the OER electrocatalyst, the obtained NG membrane displays much promoted catalytic activity and stability, which is comparable or even superior to those previously reported metal-free electrocatalysts for OER. Obviously, this work provides a good guidance on developing low-cost and high-performance metal-free electrocatalysts for energy-related electrocatalytic reactions.