Morphology effect on the enhanced photocatalytic activity of potassium doped graphitic carbon nitride microtubes

Graphitic carbon nitride (CN) microtubes doped with potassium were prepared by a hydrothermal reaction of melamine and potassium hydroxide and subsequent calcination at elevated temperature. Both potassium doping and microtube forming increase the specific surface area of 0.20MK-CN to 147.06 m(2)/g, compared with 28.57 m(2)/g of CN. The photocurrent and EIS measurements show that K doping promoted the charge separation and migration of 0.20MK-CN photocatalysts. The photocatalytic hydrogen evolution rate for 0.20MK-CN reaches to 11.4 mu mol/h, which is 10.8 times that of pure phase CN. The enhanced photocatalytic hydrogen evolution can be ascribed to the enhanced separation and transfer of photoinduced electron/hole pairs for the intraplane heterojunction of CN/K-CN domain.