Highly efficient photocatalytic TiO2- and SrTiO3-based films synthesised by liquid phase deposition

The development of efficient photocatalytic materials requires thin oxide films that ensure high stability and effective charge separation. Although TiO 2 and SrTiO 3 are widely used photocatalysts, their performance is limited by rapid electron-hole recombination. Constructing TiO 2 /SrTiO 3 heterojunctions using a scalable, low-temperature Liquid Phase Deposition (LPD) method offers a promising strategy to overcome this limitation. In this work, single-layer and sandwich-like TiO 2 -SrTiO 3 coatings were prepared on FTO using LPD and characterised by XRD, FIB-SEM cross-section analysis, ToF-SIMS depth profiling, impedance spectroscopy, and photoelectrochemical measurements. The LPD process enabled the production of uniform, composition-controlled films with well-defined interfaces. The multilayer heterostructures exhibited photocatalytic activity in terephthalic acid hydroxylation and nitroaromatic reduction. Additionally, a favourable effect of the sandwich-like structure on photocatalytic activity was observed for the hydrogen evolution reaction (exceeding the H 2 generation rate almost three times compared to the plain films), which is attributed to improved charge separation and directional carrier transport at the engineered oxide interfaces. These results show that LPD is a versatile approach for producing homogeneous, stable, and photoactive TiO 2 /SrTiO 3 heterostructures. The enhanced performance of the sandwich-like films highlights the crucial role of interface design in optimising materials for specific photocatalytic applications. This work presents the synthesis of efficient photocatalytic films based on anatase and strontium titanate using the liquid phase deposition method. The photocatalytic activity of the layers was tested using three different reactions: terephthalic acid hydroxylation, reduction of nitroaromatic compounds, and hydrogen evolution.