One-Dimensional Densely Aligned Perovskite-Decorated Semiconductor Heterojunctions with Enhanced Photocatalytic Activity

By using one-dimensional rutile TiO2 nanorod arrays as the structure-directing scaffold as well as the TiO2 source to two consecutive hydrothermal reactions, densely aligned SrTiO3-modified rutile TiO2 heterojunction photocatalysts are crafted for the first time. The first hydrothermal processing yielded nanostructured rutile TiO2 with the hollow openings on the top of nanorods (i.e., partially etched rutile TiO2 nanorod arrays; denoted PE-TNRAs). The subsequent second hydrothermal treatment in the presence of Sr2+ transforms the surface of partially etched rutile TiO2 nanorods into SrTiO3 nanoparticles via the concurrent dissolution of TiO2 and precipitation of SrTiO3 while retaining the cylindrical shape (i.e., forming SrTiO3-decorated rutile TiO2 composite nanorods; denoted STO-TNRAs). The structural and composition characterizations substantiate the success in achieving STO-TNRA nanostructures. In comparison to PE-TNRAs, STO-TNRA photocatalysts exhibit higher photocurrents and larger photocatalytic degradation rates of methylene blue (3.21 times over PE-TNRAs) under UV light illumination as a direct consequence of improved charge carrier mobility and enhanced electron/hole separation. Such 1D perovskite-decorated semiconductor nanoarrays are very attractive for optoelectronic applications in photovoltaics, photocatalytic hydrogen production, among other areas.