Metal Oxide Nanosurfaces and Hetero-Interfaces for Solar Harvesting Applications

Metal oxide nanostructures with hetero-contacts and phase boundaries offer unique platform for designing materials architectures for solar harvesting applications. Besides the size and surface effects, the modulation of electronic behavior due to junction properties leads to modify surface states that promote higher efficiency. The growing possibilities of engineering nanostructures in various compositions (pure, doped, composites, heterostructures) and forms (particles, tubes, wires, films) has intensified the research on the integration of different functional material units in a single architecture to obtain new materials for solar energy harvesting application.

In this work we present the deposition and modification of semiconducting metal oxides and their multilayers (TiO₂, Fe₂O₃ and TiO₂/Fe₂O₃) for photoelectrochemical (PEC) hydrogen production. The deposition parameters for thin film creation were optimized with respect to the PEC performance of the resulting materials in both alkali solution and simulated seawater. The long-term performances of the metal oxide photoanodes were determined in alkali and seawater electrolyte, as well. The results presented that the multilayered TiO₂/Fe₂O₃ photonanode yielded higher photocurrent density (ca 2mA at 1.23 V) with very stable conditions even after 1-week measurement.