|
" Design and Characterization of Active Photocataylysts Based on Transition Metal Chalcogenides "
Tanışık, İrem
Koca, Atıf
| Document Type
|
:
|
Latin Dissertation
|
| Language of Document
|
:
|
English
|
| Record Number
|
:
|
1109873
|
| Doc. No
|
:
|
TLpq2476853493
|
| Main Entry
|
:
|
Koca, Atıf
|
|
|
:
|
Tanışık, İrem
|
| Title & Author
|
:
|
Design and Characterization of Active Photocataylysts Based on Transition Metal Chalcogenides\ Tanışık, İremKoca, Atıf
|
| College
|
:
|
Marmara Universitesi (Turkey)
|
| Date
|
:
|
2019
|
| student score
|
:
|
2019
|
| Degree
|
:
|
Master's
|
| Page No
|
:
|
68
|
| Abstract
|
:
|
The use of fossil fuels causes CO2 emissions. In recent years, the tendency to use alternative energy sources has increased due to increased environmental concerns. Among the alternative energy sources, studies on hydrogen energy have accelerated. Hydrogen as an energy source is obtained both from fossil fuels or electrolysis of water. Up to today, hydrogen production has mostly been derived from fossil sources. However, since these approaches are considered as non-environmentally friendly, and clean; hydrogen energy in the energy sector has not been able to pay attention. In recent years, researches are concentrated on hydrogen production from water studies on the production of hydrogen from water by using solar energy have intensified. In the photocatalytic hydrogen production, the catalysts have an important place. CdxZn(1-x)S is one of the most preferred photocatalysts due to their controllable band cavities and their excellent resistance to corrosion. Therefore, CdxZn(1-x)S and RGO-CdxZn(1-x)S photocatalysts were synthesized using different x values in this thesis study and hydrogen activities were analysed. CdxZn(1-x)S photocatalysts with different compositions were synthesized by the thermal sulphurization technique and the these photocatalysts were decorated with reduced graphene oxide (RGO) to enhance photocatalytic activity. To determine crystal systems, lattice parameters, band spacing and surface morphologies, produced photocatalysts were characterized by X-Ray diffractometer (XRD), Ultraviole-visible (UV-VIS) spectrophotometer, scanning electron microscope (SEM) and Raman spectrophotometer. Subsequently, hydrogen efficiency of CdxZn(1-x)S and RGO-CdxZn(1-x)S composites were analysed. Structures of photocatalysts were characterized by XRD, EDS and Raman spectra. Presence of RGO in RGO-CdxZn(1-x)S has proven by these analysis. As RGO has a high electron conductivity which increases electron transfer rate, adsorption capacity and extended light absorption range, RGO-CdxZn(1-x)S photocatalysts have higher photocatalytic activity. The RGO-Cd0.7Zn0.3S photocatalyst having 2.86 eV band gap was found to be the most suitable photocatalyst for hydrogen production with 141.6 µmolh-1 hydrogen production and 19.4 % quantum efficiency. Since high crystallinity has observed from thermal sulphurization method, Cd0.7Zn0.3S photocatalyst produced by thermal sulphurization method has higher rate of hydrogen production than Cd0.7Zn0.3S photocatalysts produced by different methods.
|
| Subject
|
:
|
Alternative energy
|
|
|
:
|
Chemistry
|
| |