Graphitic carbon nitride (g-C3N4) has emerged as a visible-light responsive photocatalyst for solar energy utilization but still suffers from the deficiency of small surface area and low efficiency of charge separation. Herein, for the first time, a solvent-free vapor-solid deposition-transition strategy was developed to fabricate radially oriented nanosheets assembled hollow and tubular g-C3N4 hierarchical structures using the low-cost and non-toxic melamine precursor. This straightforward and effective strategy involves simultaneous evaporation, vapor-solid deposition and transition of melamine on the silica surface. The proper interaction between melamine and the silica surface plays a crucial role in enhancing the capture of melamine, facilitating the surface enrichment of melamine, promoting the polymerization and therefore avoiding uncontrolled polymerization. Compared with the traditional pre-casting method, the new strategy is superior because of its simplicity in operation, capability in morphological control and sustainability with melamine precursor. The as-prepared hollow and tubular g-C3N4 present significant enhancement in visible-light photoactivity due to the enlarged surface area and electron-hole separation efficiency, with dramatic increase in the rate constants up to 14 and 24 times for hollow and tubular g-C3N4 over the bulk one, respectively. The present work not only provides a versatile method for morphological control for g-C3N4, but as also a new approach for enhancing the light trapping and charge separation for photocatalysts.

Controllable hierarchical assembly of hollow tubular g-C3N4 with radially oriented nanosheets by solvent-free vapor-solid deposition-transition strategy

255th National Meeting (2018)

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