Preparation of SrTiO₃ nanocubes by CO₂ laser vaporization (LAVA) and hydrothermal maturation

SrTiO₃ is of particular interest for numerous applications such as photocatalytic water splitting, as an electrode material for thermoelectrics or as piezoceramics for sensors. Here we report on an advanced CO₂ laser vaporization (LAVA) method for the production of faceted, single-phase SrTiO₃ nanoparticles with an average particle size of 35 nm. Starting from a coarse SrTiO₃ raw powder, spherical SrTiO₃ nanoparticles were obtained by a laser-induced gas-phase condensation process. The composition of the nanoparticles corresponds to that of the starting powder, as XRD and FT-IR measurements show. Further hydrothermal treatment at 275 °C for 4 hours leads to the formation of faceted nanocubes with increasing crystallite size, as demonstrated by TEM, HR-TEM and XRD measurements. During a final washing step in 0.1 M HCl, SrCO₃ impurities were dissolved and thus single-phase SrTiO₃ nanocubes were successfully obtained, as shown by FT-IR, XRD and TEM analyses. The presented process facilitates the production of single-phase, highly crystalline SrTiO₃ nanopowders in sufficient quantities for subsequent use in a variety of applications, in particular for hydrogen production by photocatalytic water splitting.