The g-C3N4 Quantum Dot Decorated g-C3N4 Sheet/Reduced Graphene Oxide Composite as Efficient Metal-Free Electrocatalyst for Oxygen Reduction Reaction

Abstract

To develop feasible oxygen reduction reaction (ORR) for fuel cell technology and metal-air battery, it is crucial to find suitable replacement for platinum-based noble metal catalysts. N-doped carbon materials specially for graphene have been intensively investigated and proved to be efficient for ORR. In this work, to enhance performance of graphene-based electrocatalyst, we develop a facile method to prepare g-C3N4 quantum dot (QD) decorated g-C3N4 sheet/reduced graphene oxide (rGO) composite for efficient ORR. At first, a hydrothermal reaction gives a 3D g-C3N4 sheet/rGO matrix. Then, the g-C3N4 QDs are attached to the 3D g-C3N4 sheet/rGO matrix by simple stirring. The obtained product has high nitrogen content and provides sufficient active sites for ORR, showing excellent catalytic performance compared with Pt/C, which is attributed to as follows: the 3D honeycomb structure provides larger specific surface area for ORR; the addition of g-C3N4 QDs provides sufficient active sites to increase the reaction efficiency; high nitrogen content plays an important role in the progress for the oxygen reduction reaction. Present work provides possibility for the commercial application of non-metallic catalysts for ORR.