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Silas Mathuku, 2023
ABSTRACT Today’s society is mainly dependent on fossil energy sources despite being not sustainab... more ABSTRACT
Today’s society is mainly dependent on fossil energy sources despite being not sustainable, not
renewable, and not environmentally friendly, as they generate a lot of carbon dioxide. Hydrogen
is a promising substitute for fossil fuels. It is a clean fuel with water as the only oxidation
product, thus less production of CO2. Cadmium telluride (CdTe) is a promising semiconductor
material that could facilitate the use of solar energy in producing hydrogen gas. CdTe can be a ptype photoelectrode that can perform electron transfer processes with an electrolyte. As a
cathode, it reduces hydrogen ions in water to form hydrogen gas. Spray pyrolysis method, which
is simple and easy to use, cheap compared to vacuum deposition methods, can produce uniform
films over large surfaces within a short time, many small substrates at the same time, and whose
concentration of precursor solution remains constant with time, was used in this project. CdTe
films for this project were fabricated on stainless steel 304 substrates at different substrate
temperatures and spray times. The precursor solution was based on a mixture of CdCl2, TeO2,
hydrazine, and EDTA. Characterization of the fabricated films was done using X-ray
diffraction, scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS),
stylus profilometry, cyclic voltammetry, and linear sweep voltammetry. The fabricated CdTe
films had a uniform and highly crystalline surface morphology, that was Te-rich (p-type) and
exhibited photoactivity with the evolution of hydrogen gas. The best photoelectrode was
fabricated by spraying a mixture of equal volumes of 0.02 M solutions of Cd and Te salts onto a
SS 304 substrate held at 330 oC for 3 min, which produced a 10 µm-thick film and a
photocurrent of 5800 µA/cm2
observed at -0.5 V. When a dispersion of Pt catalyst was reduced
onto it, a photocurrent of 7700 µA/cm2 was observed at -0.5 V, which compares well with other
fabrication methods.
Silas Mathuku, 2023
ABSTRACT Today’s society is mainly dependent on fossil energy sources despite being not sustainab... more ABSTRACT
Today’s society is mainly dependent on fossil energy sources despite being not sustainable, not
renewable, and not environmentally friendly, as they generate a lot of carbon dioxide. Hydrogen
is a promising substitute for fossil fuels. It is a clean fuel with water as the only oxidation
product, thus less production of CO2. Cadmium telluride (CdTe) is a promising semiconductor
material that could facilitate the use of solar energy in producing hydrogen gas. CdTe can be a ptype photoelectrode that can perform electron transfer processes with an electrolyte. As a
cathode, it reduces hydrogen ions in water to form hydrogen gas. Spray pyrolysis method, which
is simple and easy to use, cheap compared to vacuum deposition methods, can produce uniform
films over large surfaces within a short time, many small substrates at the same time, and whose
concentration of precursor solution remains constant with time, was used in this project. CdTe
films for this project were fabricated on stainless steel 304 substrates at different substrate
temperatures and spray times. The precursor solution was based on a mixture of CdCl2, TeO2,
hydrazine, and EDTA. Characterization of the fabricated films was done using X-ray
diffraction, scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS),
stylus profilometry, cyclic voltammetry, and linear sweep voltammetry. The fabricated CdTe
films had a uniform and highly crystalline surface morphology, that was Te-rich (p-type) and
exhibited photoactivity with the evolution of hydrogen gas. The best photoelectrode was
fabricated by spraying a mixture of equal volumes of 0.02 M solutions of Cd and Te salts onto a
SS 304 substrate held at 330 oC for 3 min, which produced a 10 µm-thick film and a
photocurrent of 5800 µA/cm2
observed at -0.5 V. When a dispersion of Pt catalyst was reduced
onto it, a photocurrent of 7700 µA/cm2 was observed at -0.5 V, which compares well with other
fabrication methods.