In situ construction of cyano-modified g-C3N4 nanolayer-coated SrTiO3 nanotubes by gas-solid reaction for efficient photocatalytic solar fuel production

For the transformation of the global energy structure, photocatalyst-based artificial photosynthesis for solar-to-chemical energy conversion has been regarded as promising. Herein, we report the homogenous construction of cyano-modified g-C3N4 ultrathin nanolayers onto SrTiO3 nanotubes using a simple one-step gas–solid reaction, as well as their application to photocatalytic H2 evolution and CO2 reduction. The creation of one-dimensional core–shell nanostructures and type II heterojunctions broaden visible light absorption range and shorten charge transfer path. The electron-absorbing cyano introduced in situ without any auxiliary salts can not only provide an appropriate driving force for electron transport and extend the active site of photocatalytic reaction, but also alter the band gap to accomplish energy band alignment. Moreover, in-situ irradiation X-ray photoelectron spectroscopy (ISI-XPS) was used to confirm the dual active site system consisting of cyano and SrTiO3. This work aims to promote the development of the surface modification of core-shell nanostructured photocatalysts.