Incorporating a novel metal-free interlayer into g-C3N4 framework for efficiency enhanced photocatalytic H2 evolution activity

Graphitic carbon nitride (g-C3N4) has become a research hotspot recently owing to its unique advantage and wide application in the field of photocatalysis. However, the photocatalytic activity of the traditional two-dimensional g-C3N4 material is unsatisfactory owing to the relatively narrow visible light responsive region and high recombination probability of photogenerated charge carriers. Here, the novel nonmetal interlayer incorporated into the g-C3N4 framework is successfully fabricated by thermal polymerization of the beta-cyclodextrin (beta-CD) and melamine as precursors, which significantly enhances the photocatalytic performance for H-2 evolution than that from g-C3N4. The corresponding characterization methods demonstrate that the interlayer is composed of oxygen-contained graphitized carbon as well as the enhanced photocatalytic activity originates from the narrowed band gap, negative-shifted conduction band position and efficient charge transfer caused by this metal-free interlayer incorporation. It not only results in the form of the C-O-C bonding between the interlayer and g-C3N4 but also can bridge the interlayer and extend the pi-conjugated system, which facilitate the charge-carrier migration and separation. The current work could provide new insights for constructing other high performance, low-cost and metal-free photocatalyst for H-2 evolution. (C) 2016 Elsevier B.V. All rights reserved.