6,7Īmong their methods, heterogeneous photocatalysts were regarded as an effective way to improve photocatalytic activity, since heterojunctions can promote charge migration across both the semiconductor/electrolyte and the semiconductor/photoelectrode interface effectively separating photogenerated electrons and holes.
4,5 And metal modification of TiO 2 to increase photocatalytic properties of nanoparticles were reported also. Metal/nonmetal element doping or decoration was developed to increase its photoactivity, for example, TiO 2 modification with carbon nanolayers used as a photocatalyst led to an enhanced efficiency due to the increased substrate adsorption in the vicinity of the photocatalytic sites and high migration efficiency of photoinduced electrons at the carbon/TiO 2 interface. 2,3 However, the energy unitization efficiency of TiO 2 is limited because of its wide band gap and the rapid recombination of photogenerated electron–hole pairs.
1 For example, oriented, single-crystalline rutile TiO 2 nanorod films on transparent conductive fluorine-doped tin oxide (FTO) substrates or carbon fiber were used as dye-sensitized solar cells (DSSCs) and exhibited an improved cell performance due to a direct connection of the point of photogeneration with the collection electrode.
Introduction TiO 2, as one of the widest band gap semiconductors (∼3.0 eV), is widely used in photocatalysts and photoelectrodes due to its strong optical absorption, favorable band edge positions, and abundant availability. The detector has reproducible and flexible properties, as well as an enhanced photosensitive performance. Furthermore, the mechanism behind this was discussed. The evolution of hydrogen according to the photo-catalytic water-splitting process showed that Sn 3O 4/TiO 2 heterostructures have a good photocatalytic hydrogen evolution activity with the rate of 5.23 μmol h −1, which is significantly larger than that of Sn 3O 4 nanoflakes (0.40 μmol h −1) and TiO 2 nanorods (1.13 μmol h −1). TiO 3O 4 heterostructures exhibit a stable photocurrent of 180 μA, which is a 4-fold increase with respect to that of the Sn 3O 4 nanoflakes on carbon paper, and a two-order increase with respect to that of the TiO 2 NRs arrays. To better utilize solar energy, TiO 3O 4 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. Semiconductor heterostructures are regarded as an efficient way to improve the photocurrent in photoelectrochemical cell-type (PEC) photodetectors.
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