Currently,photocatalytic water splitting is regarded as promising technology in renewable energy gen-eration.However,the conversion efficiency suffers great restriction due to the rapid recombination of charge carriers.Rational designed the structure and doping elements become important alternative routes to improve the performance of photocatalyst.In this work,we rational designed oxygen-doped graphitic carbon nitride(OCN)nanotubes derived from supermolecular intermediates for photocatalytic water splitting.The as prepared OCN nanotubes exhibit an outstanding hydrogen evolution rate of 73.84 μmol h-1,outperforming the most of reported one dimensional(1D)g-C3N4 previously.Due to the rational oxygen doping,the band structure of g-C3N4 is meliorated,which can narrow the band gap and reduce the recombination rate of photogenerated carriers.Furthermore,the hollow nanotube structure of OCN also provide multiple diffuse reflection during photocatalytic reaction,which can signif-icantly promote the utilization capacity of visible light and enhance the photocatalytic water splitting performance.It is believed that our work not only rationally controls the nanostructure,but also intro-duces useful heteroatom into the matrix of photocatalyst,which provides an effective way to design high-efficiency g-C3N4 photocatalyst.