An alkali treating strategy for the colloidization of graphitic carbon nitride and its excellent photocatalytic performance.

The colloid of graphitic carbon nitride (g-C3N4) was of great importance for practical application. Herein we introduced an alkali treatment route to efficiently colloidize g-C3N4 under mild conditions by destroying the hydrogen bonds between linearly polymeric melon chains and hydrolyzing partial C−NH−C bonds linked two tri-s-triazine units. The obtained colloidal suspension was extremely stable due to its negative charges on surface, and the particle size of several hundred nanometers and the nanobelt-like morphology were revealed by electron microscopy and dynamic light scattering technologies. The structural, optical and functional group analysis demonstrated that the structure of CN heterocycles was preserved after the alkali treatment, and the produced colloidal g-C3N4 can be re-assembled by an electrostatic interaction. Moreover, contributing to the reduced electron-hole recombination, the photocatalytic performance of restacked carbon nitride colloids had more enhanced photocatalytic performance than bulk g-C3N4.

The amphoteric properties of g-C3N4 nanosheets and fabrication of their relevant heterostructure photocatalysts by an electrostatic re-assembly route.

A stable colloid of g-C3N4 nanosheets was prepared on a large scale via a H2SO4 exfoliation route. The amphoteric nature due to the simultaneous presence of carboxyl and amino groups provided a strategy to fabricate heterostructures by an electrostatic re-assembly between g-C3N4 nanosheets and various charged guests in different pH systems.