| Popis: |
Hydrogen stands as a good energy vector to replace fossil fuels due to its high energy density and green production. Moreover, hydrogen can be used to complement other green energy sources. One of the most craved methods to harvest H2 is photocatalysis: semiconductor catalysts when irradiated by the solar light produces charge carriers that can intervene and enhance the rate of REDOX reactions. The parallelism with photovoltaics is obvious, we need energetically and spatially separated charge carriers such that recombination is avoided and they can intervene in the desired processes. Therefore this work aims to use one of the most recent change of paradigm in photovoltaic cells to enhance efficiency: Selective contacts. With this approach cells are understood as an absorber and two filters that let one charge carrier out and blocks the other. Consequently, we will consider photocatalyst as such. To do so, P90 T iO2 based catalysts where used to optimize the experimental set-up while the P90 T iO2/Au production was increased by 15% with a simple heat treatment. Bismuth vanadate absorbers have been used to verify the filtering behavior of several metal co-catalyst, even thought the overall production was low. Hence, a quick Z-scheme structure was synthesised to combine bismuth vanadate with titanium dioxide leading to poor results but opening the door for another interesting research path. In addition, silicon supported titania sol-gel thin films where used to selectively deposited new selective charge carrier filters resembling the patterned contacts of Interdigitated Back-Contacted photovoltaic cells. Amorphous silicon and magnesium electron transport layers were paired with gold nanoparticles as hole transport layer. From that, a highly interdigitated magnesium pattern was able to double the production of the sol-gel titania and gold nanoparticles reference sample. Furthermore, the increase in efficiency due to pattern optimisation and selective contact use, accurately fitted the Langmuir–Hinshelwood Kinetic Model for heterogeneous catalysis. |
