Hierarchical assembly of TiO₂-SrTiO₃ heterostructures on conductive SnO₂ backbone nanobelts for enhanced photoelectrochemical and photocatalytic performance

Heterostructures can play a role in enhanced photoinduced electrochemical and catalytic reactions due to the advantageous combination of two compounds. Herein, we demonstrate the fabrication of Sb:SnO₂@TiO₂-SrTiO₃ 3D heterostructures via a simple hydrothermal method using a conductive Sb:SnO₂@TiO₂ nanobelt electrode as a template. XRD, FESEM, and TEM analyses confirm that a well-dispersed and crystalized SrTiO₃ layer is formed on the surface of TiO₂ nanorods. The photoelectrochemical (PEC) performance of the heterostructure is optimized by controlling the reaction time. Details about the effect of the hydrothermal reaction time on the PEC performance are discussed. The optimized Sb:SnO₂@TiO₂-SrTiO₃ heterostructure exhibited a higher onset potential and a saturated photocurrent in comparison to the Sb:SnO₂@TiO₂ nanostructure. The result is attributed to a Fermi level shift and a blocking layer effect caused by the SrTiO₃. Furthermore, the photocatalytic degradation of methylene blue was significantly enhanced on the optimized Sb:SnO₂@TiO₂-SrTiO₃. This work demonstrates that a synergetic effect between three-dimensional nanoarchitecturing and a heterojunction structure is responsible for enhanced PEC as well as improved photocatalytic performance levels, both of which can be extended to other metal-oxide and/or ternary compounds.