Nanoconfined fusion of g-C3N4 within edge-rich vertically oriented graphene hierarchical networks for high-performance photocatalytic hydrogen evolution utilizing superhydrophillic and superaerophobic responses in seawater

Two-dimensional photocatalysts often suffer severe aggregation due to the inevitable van der Waals forces between nanosheets, which limits their photocatalytic water-splitting efficiency. Herein, a rational design of confined synthesis of g-C3N4 nanomeshes (GCN) on N-doped vertically-oriented graphene (NVG) arrays for enhanced hydrogen evolution is reported. The aggregation of 2D g-C3N4 nanosheets is effectively avoided via physical separation by electrically conductive NVG networks. Well-defined hierarchical architecture of the GCN/NVG photocatalyst endows with superaerophobicity and simultaneously enhanced light absorption. Experimental and ab initio simulation results suggest that the protruding graphene edges induce charge redistribution, thus enhancing interfacial charge separation. The GCN/NVG samples demonstrate a high areal hydrogen evolution rate of 41.7 mu mol h(-1) cm(-2) (225L m(-2) in 24h, STP) in water and 45.8 mu mol h(-1) cm(-2) (246.2 L m(-2) in 24 h, STP) in simulated seawater. This work creates further opportunities for the development of earth-abundant photocatalysts.

Automated summary

In this study, a rational design of confined synthesis of g-C3N4 nanomeshes on N-doped vertically-oriented graphene arrays was reported for enhanced hydrogen evolution. The well-defined hierarchical architecture of the GCN/NVG photocatalyst not only effectively avoided aggregation of 2D g-C3N4 nanosheets, but also demonstrated superaerophobicity and enhanced light absorption. Experimental and simulation results suggest that the protruding graphene edges induce charge redistribution, leading to enhanced interfacial charge separation and high hydrogen evolution rates in water and simulated seawater.