Ti/TiO_2/Cu_2O Electrodes for Photocatalytic Applications: Synthesis and Characterization

摘要

Energy from renewables (solar, photovoltaic, geothermal), is a major challenge for researchers' efforts in reason of the intermittent nature of these energy sources. Systems like photoelectrochemical (PEC) cells are promising devices that allow the direct conversion of solar energy into electric power and/or chemical fuels. The direct conversion of solar energy in fuels can be achieved using photocatalysts, based on semiconductors like TiO_2. In this work TiO_2 nanotubes were achieved through "one-step" anodization of titanium, a low cost and accurate method which allowed to control dimensions and morphology of the nano structured Ti/TiO_2 electrodes. Central limit for TiO_2 photoconversion efficiency is its wide bandgap (i.e. ~3.2eV), which limits light absorption to the ultraviolet region (3-5% of the solar radiation). Composite Cu_2O/TiO_2 systems have attracted much attention: Cu_2O is a promising semiconductor material (bandgap 2.0-2.6eV), suitable to absorb visible light. Traditionally, Cu_2O deposition techniques include the impregnation of TiO_2 with a copper salt and subsequent calcination, but offers little control on sizes, shape and deposit's composition. In this work we developed an electrodeposition method in order to control Cu_2O morphology and sizes in the composed Ti/TiO_2/Cu_2O electrodes.