Title Electrodeposition and characterization of photo-/electrocatalytic MoS2 and WO3 films for water splitting catalysis /
Translation of Title Foto-/elektrokatalizinių MoS2 ir WO3 plonų sluoksnių elektrocheminis nusodinimas ir pritaikymas vandens skaidymo katalizei.
Authors Levinas, Ramūnas
DOI 10.15388/vu.thesis.204
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Pages 168
Keywords [eng] electrochemistry ; anodization ; photocatalysis ; hydrogen evolution reaction
Abstract [eng] Photo-/electrocatalytic water splitting is a simple way to produce green hydrogen without the emission of any undesirable by-products. Upon application of a sufficient electrical potential, a water molecule is split into oxygen and hydrogen. The energy required to drive this process can be reduced by heterogeneous catalysis. The work presented in this thesis was aimed at the electrochemical synthesis and application of molybdenum sulfide (MoS2) for hydrogen evolution reaction (HER) catalysis, and tungsten oxide (WO3) for oxygen evolution photocatalysis. Thin MoS2 films were electrochemically deposited on flat (wire) and 3D (metallic foam) substrates. A combination of steady-state and alternating current experiments was used to characterize the catalytic activity of these films. It was found by electrochemical impedance spectroscopy that one parameter – hydrogen adsorption resistance – is directly correlated to HER activity in acidic media. WO3 films were synthesized by anodization; a tunable thickness and morphology was achieved. Plain WO3 films were modified by cathodic H+ intercalation, whereas a composite WO3+MoSx film was prepared by co-deposition. The three materials were tested for their photocatalytic activity under 365 nm illumination. The enhanced photocatalytic activity of modified films was tied to increased photoconductivity, which itself is a result of improved charge carrier photogeneration and/or separation.
Dissertation Institution Vilniaus universitetas.
Type Doctoral thesis
Language English
Publication date 2021