TiO₂@Sn₃O₄ nanorods vertically aligned on carbon fiber papers for enhanced photoelectrochemical performance

Semiconductor heterostructures are regarded as an efficient way to improve the photocurrent in photoelectrochemical cell-type (PEC) photodetectors. To better utilize solar energy, TiO₂@Sn₃O₄ arrays vertically aligned on carbon fiber papers were synthesized via a hydrothermal route with a two-step method and used as photoanodes in a self-powered photoelectrochemical cell-type (PEC) photodetector under visible light. TiO₂@Sn₃O₄ heterostructures exhibit a stable photocurrent of 180 μA, which is a 4-fold increase with respect to that of the Sn₃O₄ nanoflakes on carbon paper, and a two-order increase with respect to that of the TiO₂ NRs arrays. The evolution of hydrogen according to the photo-catalytic water-splitting process showed that Sn₃O₄/TiO₂ heterostructures have a good photocatalytic hydrogen evolution activity with the rate of 5.23 μmol h^-1, which is significantly larger than that of Sn₃O₄ nanoflakes (0.40 μmol h^-1) and TiO₂ nanorods (1.13 μmol h^-1). Furthermore, the mechanism behind this was discussed. The detector has reproducible and flexible properties, as well as an enhanced photosensitive performance.