Integration of the synthesis strategies to improve the charge carriers transport a...
| Grant number: | 14/22388-3 |
| Support type: | Scholarships abroad - Research Internship - Post-doctor |
| Effective date (Start): | February 01, 2015 |
| Effective date (End): | January 31, 2016 |
| Field of knowledge: | Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry |
| Principal Investigator: | Ana Flávia Nogueira |
| Grantee: | Mauricio Alves de Melo Junior |
| Supervisor abroad: | Frank E. Osterloh |
| Home Institution: | Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil |
| Local de pesquisa : | University of California, Davis (UC Davis), United States |
| Associated to the scholarship: | 13/05654-9 - TiO2-PILLARED layered solids doped with nanoparticles for carbon dioxide photoreduction and water splitting, BP.PD |
Abstract The development of porous titanium and niobium-based semiconductors, obtained from the pillaring of lamellar K2Ti4O9 and K4Nb6O17 solids, and their decoration with different co-catalysts nanoparticles, to be applied as photocatalysts for the production of H2 from water splitting is proposed in this research project. The expansible features of the lamellar structures of K2Ti4O9 and K4Nb6O17 will be explored for the introduction of titanium dioxide (TiO2) pillars into their interlamellar spaces through the pillaring process, creating new photoactive sites as well as increasing the surface area and stabilities of the materials. Unfortunately, such configuration makes these pillared semiconductors only able to absorb ultraviolet radiation, which corresponds to less than 6 % of the solar spectrum, because of the relative high band gap values of niobate, titanate and TiO2 semiconductors, which are higher than 3.0 eV. Thus, in the aim of overcoming this restriction, the pillared solids will be decorated with the co-catalysts Au, Ag, and NiO nanoparticles, to promote a wider absorption of the solar spectrum and/or favor the suppression of the fast electron-hole recombination. The synthesized materials will be characterized by largely applied techniques such as X-ray diffraction, scanning and transmission electron microscopy, thermogravimetry, diffuse reflectance spectroscopy, elemental analysis, infrared spectroscopy, and transient absorption spectroscopy. More specifically, the photochemical charge separation on the nanoscale, responsible for the water splitting phenomenon, will be analyzed through surface photovoltage spectroscopy (SPS), which probes contact potential difference changes on the materials upon excitation with sunlight. This technique will be useful to elucidate the mechanism of photovoltage origin in each case, and the results will be correlated with the amount of hydrogen generated through water splitting under solar light. (AU) | |