Bottom-up fabrication of graphitic carbon nitride nanosheets modified with porphyrin via covalent bonding for photocatalytic H₂ evolution

In order to broaden the absorption range of graphitic carbon nitride, one of the common methods is to couple the well-known photosensitizer porphyrin with graphitic carbon nitride through van der Waals weak interactions. To date, to combine porphyrin with graphitic carbon nitride through covalent interactions has not been settled. In this work, through rational molecular design, we successfully incorporated porphyrin into the matrixes of graphitic carbon nitride by covalent bonding via one-pot thermal copolymerization. The resultant material not only can widen the absorption range but also possess the enlarged specific surface area and construction intramolecular heterojunctions which can contribute to improve electron-holes separation efficiency. The resultant photocatalyst exhibited enhanced H₂ production rate (7.6 mmol·g^-1·h^-1) and with the apparent quantum efficiency (AQE) of 13.3% at 450 nm. At the same time, this method opens a way to fabricate graphitic carbon nitride nanosheets via bottom-up strategy.