Hematite (Fe2O3) photoelectrode is a promising candidate for hydrogen production via water splitting because of its favorable band gap, low cost, and abundance in nature. However, its photoactivity is limited by the poor absorptivity and carrier mobility, slow water oxidation kinetics, and short hole diffusion length. Metallic nanoparticles, such as Au, Cu and Ag, exhibit localized surface plasmon resonances (LSPR) and are well-suitable to improve the optoelectronic properties of hematite, in particular for thin films. Several mechanisms have been proposed to explain the observed LSPR mediated photoelectrochemical performance enhancement. The synergistic effect of the metallic nanoparticle-modified thin hematite photoelectrode combination is an important step to understand how the donor density is increased. However, one of the main problems found it was the comprehension of each mechanisms in interface of metallic nanoparticle-modified hematite/electrolyte for oxygen evolution reaction. In order to clarify the transport properties, the proposal for this internship is to evaluate the photogenerated charges dynamics by transient absorption spectroscopy (TAS), observing the transport mechanism for bare and modified hematite photoelectrodes and the implications at their interfaces. The results achieved will directly applicable to other semiconductors with similar properties to hematite and are expected to be helpful in future design of optimized photoanodes, where, for instance, metal nanoparticle functionalization will be combined with doping and introduction of nanostructured materials.
News published in Agência FAPESP Newsletter about the scholarship: