Porous and low-defect graphitic carbon nitride (g-C3N4) nanotubes were fabricated through heating precursors synthesized by recrystallization from H2SO4/methanol. The textural and chemical structures of the as-prepared samples were well studied. Recrystallization and subsequent heating result in g-C3N4 nanotubes with developed porosity and high specific surface area. Unexpectedly, the nanotubes exhibit much ordered tri-s-triazine conjugated network and fewer defects. Compared to bulk g-C3N4 prepared by direct heating melamine, the nanotubes demonstrate enhanced photocatalytic activity for hydrogen evolution under visible light irradiation. Besides the improved textural and chemical structures, the optimized optical and electronic properties are contributed to the enhanced photocatalytic performance.
