BACKGROUND The construction of heterojunction between two-phase semiconductors is a crucial tactic to enhance photocatalytic activity due to its efficient charge separation. RESULT In this work, a novel TiO2/high-crystalline g-C3N4(HCCN) heterojunction photocatalyst was synthesized successfully via a simply hydrothermal method, which was composed of TiO(2)nanoparticles distributed on the surface of the HCCN nanosheets. The microstructure and morphology of TiO2/HCCN heterojunction were investigated by various characteristic techniques (such as X-ray diffraction, transmission electron microscopy and Fourier transform infrared). The photocatalytic performance of as-prepared photocatalysts was tested though the degradation of tetracycline (10 mg L-1) under visible light irradiation (lambda > 420 nm). Significantly, the 50% TiO2/HCCN composite photocatalyst (mass fraction of TiO(2)is 50%) exhibited the optimum photocatalytic activity (90%, 120 min), and the corresponding reaction rate constant was around 12 times and 54 times higher than those of pristine HCCN and TiO2, respectively. CONCLUSION The excellent photocatalytic performance was attributed mainly to the synergistic effect of the TiO2/HCCN heterojunction as follows: (i) enhanced light absorption capacity; (ii) improved separation and migration of electron-hole pairs; (iii) extended lifetime of photogenerated carriers. This current study extends our knowledge towards constructing other HCCN-based nanocomposites with extraordinary photocatalytic performance for addressing environmental problems. (c) 2020 Society of Chemical Industry