Protonation of Graphitic Carbon Nitride (g-C₃N₄) for an Electrostatically Self-Assembling Carbon@g-C₃N₄ Core–Shell Nanostructure toward High Hydrogen Evolution

Abstract

The development of new, appealing metal-free photocatalysts is of great significance for photocatalytic hydrogen evolution. Herein, an electrostatic self-assembly method to form a unique core–shell architecture of a colloid of carbon spheres with graphitic carbon nitride (g-C 3 N 4 ) has been developed by a one-step chemical solution route. The chemical protonation of g-C 3 N 4 solids with strong oxidizing acids (such as HNO 3 ) is an efficient pathway toward the sol procedure of stable carbon nitride colloids, which can cover the surface of carbon spheres via electrostatic adsorption. On account of the unique polymeric matrix of g-C 3 N 4 and reversible hydrogen bonding, the carbon@g-C 3 N 4 derived from the sol solution showed high mechanical stability with broadened light absorption and enhanced conductivity for charge transport. Thus, the carbon@g-C 3 N 4 core–shell structure exhibited remarkably enhanced photoelectrochemical performance. This polymer system is envisaged to hybridize with desirable functionalities (such as carbon nanorods) to form unique architectures for various applications.