Boosting the Photocatalytic Hydrogen Evolution Performance of Mg- and Cl-Doped Graphitic Carbon Nitride Microtubes

To tune its band structure by doping element and to increase the specific surface area by forming micro/nanoscale structures remain the effective means to further improve the photocatalytic performance of graphitic carbon nitride (CN). Herein, Mg- and Cl-codoped CN microtubes (MgCl2-CN) were successfully prepared by a hydrothermal reaction of melamine and magnesium chloride. The specific surface area of 1MgCl2-CN is 148.0 m2/g, about 8.3 times that of CN (17.8 m2/g). Meanwhile, Mg and Cl doping narrows the band gap of CN. Under visible light (λ > 420 nm) irradiation, the photocatalytic hydrogen evolution rate of 1MgCl2-CN reaches 8.4 μmol/h, which is 8.8 times that of CN. The synergistic effect of microtube forming and Mg/Cl doping not only increases the specific surface area, the visible light capture, but also enhances the separation and transfer of photogenerated carriers, thus improving the photocatalytic performance.