The pulsed laser ablation synthesis of colloidal iron oxide nanoparticles for the enhancement of TiO2 nanotubes photo-activity

The rapid, only a few minutes long synthesis of FeO, Fe3O4, and Fe2O3 nanoparticles mixture utilizing the pulsed laser ablation using simply pure iron target and water was demonstrated. The size and crystal phase of Fe-based NPs were characterized using DLS and HR-TEM techniques, respectively. The metastable suspension of FeO, Fe3O4, and Fe2O3 nanoparticles was used to the decoration of anodized TiO2 nanotubes (TiO2-NTs) by means of the ultrasonic bath. SEM inspection confirms preservation of the ordered morphology even upon 60 min long exposition to the ultrasounds whereas TOF SIMS indicated penetration of iron species down to the TiO2-NTs base. Finally, the electrochemical investigation of decorated and bare TiO2-NTs has shown a response typical for Fe2+/Fe3+ iron species and the boosted activity towards oxygen evolution reaction in the anodic regime. As of high importance, for the 30 min long ultrasound-assisted modification, the photocurrent was enhanced almost 2.5 times comparing to the pristine material exposed to the solar light, although differences in optical properties were negligible. Taking into account outstanding activity namely response upon irradiation and effectiveness of water splitting, the proposed approach can be regarded as a facile one generating much less waste in comparison to typical wet-chemistry methods.