Hybridized Nanowires and Cubes: A Novel Architecture of a Heterojunctioned TiO₂/SrTiO₃ Thin Film for Efficient Water Splitting

Abstract

A unique morphology of SrTiO3 nanocubes precipitated on TiO2 nanowires is successfully synthesized in the form of a thin‐film heterojunctioned TiO2/SrTiO3 photocatalyst using facile hydrothermal techniques. The formation mechanisms of the synthesized photocatalysts are meticulously studied and described. Growth of SrTiO3 single crystal nanocubes (≈50 nm in width) on anatase polycrystalline nanowires follows an in situ dissolution‐precipitation pathway. This is consonant with the classic LaMer model. By analyzing the results of field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), X‐ray diffraction (XRD), energy dispersive X‐ray (EDX) spectroscopy, X‐ray photoelectron spectroscopy (XPS), and UV‐vis spectrophotometry, a comprehensive structural and morphological characterization of the photocatalysts is established. FESEM images reveal that the anatase film comprises mainly of nanowires bristles while the tausonite film is primarily made up of nanocube aggregations. In comparison to the respective pristine semiconductor photocatalysts, the heterostructured photocatalyst demonstrates the highest efficiency in photocatalytic splitting of water to produce H2, 4.9 times that of TiO2 and 2.1 times that of SrTiO3. The enhanced photocatalytic efficiency is largely attributed to the efficient separation of photogenerated charges at heterojunctions of the two dissimilar semiconductors, as well as a negative redox potential shift in the Fermi level.

Hydrogenated TiO2/SrTiO3 porous microspheres with tunable band structure for solar-light photocatalytic H2 and O2 evolution

“…This indicates that the water-splitting reaction over the samples is associated with the DRS absorption spectra [44]. Compared with other typical TiO2/SrTiO3 nanostructures with different morphologies [26,[30][31][32][33][34], the H-TiO2/SrTiO3 heterostructured porous microspheres present much higher photocatalytic activity. This can be attributed to the synergistic effect of the unique porous sphere structure, heterostructure, and appropriate oxygen-vacancy and Ti 3+ contents, which serve as trapping sites, preventing the rapid recombination of charge carriers and improving the interfacial electron-transfer rate and the migration efficiency of photoinduced electrons.…”

“…For most of these kinds of composites, homogeneous component distribution is difficult to achieve, which hinders their catalytic application. Moreover, low visible-light utilization limits their efficiency under sunlight [32][33][34]. Thus, there is an urgent need to prepare TiO2/SrTiO3 composites with homogeneous component distribution and multichannel synergistic effects in order to provide photocatalysts with enhanced visible-light absorption and photocatalytic performance.…”

Photoassisted fabrication of zinc indium oxide/oxysulfide composite for enhanced photocatalytic H2evolution under visible-light irradiation

“…Appropriate composites can promote the separation of photoinduced electrons and holes and accordingly enhance the photocatalytic activity of H 2 evolution, because rapid recombination of photogenerated electron-hole pairs is one of the most disadvantageous factors for photocatalytic water splitting [17]. Many reports reveal that semiconductor composites can effectively suppress the recombination of photogenerated electron-hole pairs [17][18][19][20].…”

“…Many reports reveal that semiconductor composites can effectively suppress the recombination of photogenerated electron-hole pairs [17][18][19][20]. The valence bands (VBs) and conduction bands (CBs) of the semiconductors in a composite have different energies, and the resulting potential difference assists the separation of photoinduced electrons and holes [18].…”

Investigating the synergistic effects in tourmaline/TiO2-based heterogeneous photocatalysis: Underlying mechanism insights

“…The PL spectrum for all samples comprise broad luminescence bands (Fig. 5a), which would be ascribed to the radiative recombination of self-trapped excitons [28]. Peak shifts are often resulted from the electron trapping before recombination [29].…”