Title: The versatility of Fe2TiO5 as a water splitting photocatalyst

Abstract

Very recently, pseudobrookite Fe2TiO5 has been surfaced as a promising photocatalyst for the oxidation half-reaction of overall water splitting. This semiconductor is inexpensive, non-toxic, possesses a relatively small band gap, and presents adequate structural and photochemical features. In this seminar, I will talk about the performance of Fe2TiO5 nanoparticles as a suspended water splitting photocatalyst, both in the pristine form and after specific modifications, such as doping and loading of cocatalysts onto the surface of the nanoparticles. The pristine nanoparticles were synthesized through a facile solvothermal method, also used for the doping processes, whereas sputtering deposition was employed for the cocatalyst loadings. All these approaches were efficient to prolong the charge carrier’s diffusion length, reduce charge recombination, and accelerate the kinetics of the redox reactions at the solid/liquid interface, under visible light illumination. The procedure generated single-phase pristine, Sn- and Nb doped Fe2TiO5 nanoparticles with dimensions close to 30 nm and optical band gap values of 2.1 eV. When aqueous suspensions of pristine Fe2TiO5, 1.0 at% Sn-doped Fe2TiO5 and 1.5 at% Nb-doped Fe2TiO5 were irradiated by simulated sunlight for 5h, evolutions of 59.2, 297.6 and 344.0 mol h-1 g-1 of O2 were observed, respectively. These results reflect the substantial improvement that doping Fe2TiO5 with Sn and Nb confers to its photocatalytic water splitting activity. On the other hand, the deposition of nanostructured NiO, Co3O4, NiFeOx and CoFeOx cocatalysts resulted in O2 productions of 204.0, 470.4, 504.0, and 448.0 mol h-1 g-1 within 5h. Electrochemical and photoelectrochemical measurements indicated that reductions in the charge carrier transfer resistance at the solid/ liquid interface plays an important role for the performance improvements of the modified nanomaterials. Overall, this work illustrates how structural alterations of a potential photocatalyst can improve photochemical energy conversion.