Construction of 2D/2D TiO2/g-C3N4 nanosheet heterostructures with improved photocatalytic activity

Constructing two-dimensional (2D) heterostructure is an effective method to obtain highly efficient photocatalysts. In this work, 2D/2D TiO2/g-C3N4 heterostructures were constructed via in-situ growth of TiO2 nanosheets on the surface of g-C3N4 nanosheets by a facile hydrothermal co-assembly technique. The increased dispersion is favorable to expose more vacancies, which is beneficial to the enhancement of visible light absorption. This unique 2D/2D heterostructure exhibits ultrathin thickness and larger interfacial contact area, which results in shorter migration distance of photo-generated carriers to the surface and faster participation in photocatalytic water splitting. As expected, the optimized TiO2/g-C3N4 nanocomposites showed a higher photocatalytic hydrogen evolution performance under visible light irradiation than that of pristine g-C3N4 and TiO2 nanosheets. The improved performance can be attributed to the ultrathin nanosheet structure, the intimate interfacial contact and the presence of surface oxygen vacancies. More appealingly, this environment-friendly 2D/2D TiO2/g-C3N4 nanohybrid would attract more attention in water splitting.