Designed synthesis of a porous ultrathin 2D CN@graphene@CN sandwich structure for superior photocatalytic hydrogen evolution under visible light

Abstract

Graphite carbon nitride (CN) has recently become a promising photocatalyst while challenges still remain due to insufficient visible-light capture and poor electronic property. Herein, a porous ultrathin 2D CN@graphene@CN sandwich structure (5GO-CN) was prepared through in-situ local thermal oxygen erosion strategy. The inner graphene substantially accelerates the migration and separation of photogenerated charge carriers. Moreover, a small amount of oxygen-containing groups in inner graphene layer can effectively fix the thin layer of carbon nitride in the two outer surface layers. With the help of porous structure, spatially separated redox site, excellent visible light capture and fast separation of photoinduced charge carriers, this optimal 5GO-CN composite exhibited 14.3 times higher photocatalytic H2 production rate (5.58 mmol g−1 h−1) than bulk CN. The composition, microstructure and optical property of 5GO-CN sample were thoroughly investigated. This new strategy furnishes an effective way to modify other functional catalysts via using nanostructure design.