Carbon nitride nanotubes with in situ grafted hydroxyl groups for highly efficient spontaneous H2O2 production

An active and inexpensive photocatalyst for H2O2 production is desirable for industrial applications. However, obtaining high photocatalytic activity from metal-free catalysts without the use of sacrificial electron donors is difficult. Herein, g-C3N4 (CN) nanotubes functionalized with surface > OH groups that are grafted in situ were successfully synthesized via a novel alkalinization process. The nanotube structures provide a large surface area and improved mass transfer properties. In situ grafted > OH groups can capture photogenerated holes to promote separation of photogenerated charge, enabling the ready availability of electrons and hydrogen ions for H2O2 production. Further, the surface > OH groups help to suppress H2O2 self-decomposition. Consequently, a high rate of 240.36 mu mol h(-1) g(-1) of H2O2 production can be achieved without sacrificial agents, which is the highest H2O2 production in a spontaneous system for metal-free photocatalysts. This work provides a new strategy for an efficient and spontaneous H2O2 production method using a metal-free CN photocatalyst.