4.2 Cadmium-Based Nanomaterials and Hydrogen Sulfide Decomposition
41
the product is allowed to grow on the pieces of blank glass at 425 °C–475 °C for
8 h. The increase in temperature caused the increase in the size of quantum dots of
CdS0.5Se0.5/CdSe as the growth is dependent on temperature because of nucleation
and growth mechanisms. XRD and Raman spectroscopic analysis of the sample
revealed that the CdS 0.5 Se 0.5 and CdSe are monodispersed in quantum dot-glass
nanosystem and have hexagonal structure. CdSe quantum dots have size in the range
of 2–12 nm. TEM and UV–Vis spectroscopy were used to determine the quantum
confinement of CdS 0.5 Se 0.5 and CdSe. The control of CdS 0.5 Se 0.5 quantum dot size
allowed the adjustment of bandgap from 3.6 eV to 1.8 eV. This improved the absorption of visible light, which resulted in the enhanced catalytic activity. 21 and 26%
apparent quantum yields of hydrogen liberation were achieved by using CdSe and
CdS 0.5 Se 0.5 quantum dot–glass nanosystems, respectively, for the decomposition of
H 2 S [20].
4.3 Titanium-Based Nanomaterials and Hydrogen Sulfide
Decomposition
Titanium-based photocatalyst is frequently used in the decomposition of H 2 S for
the generation of H 2 . In a study, a nanocomposite was fabricated with bulk CdS
and nanocrystalline TiO 2 as the photocatalyst for the generation of hydrogen from
aqueous solution of H 2 S under visible light of the solar spectrum. For the preparation
of the CdS, aqueous solution of Na 2 S was mixed with Cd (NO 3 ) 2 and further dissolved
in isopropyl alcohol. A precipitated product was obtained which was calcined at
800 °C for 1 h. The calcination was performed in helium atmosphere so as to enhance
the crystallinity of CdS. For the synthesis of CdS/TiO 2 bulk-nanocomposite photocatalyst, the prepared CdS was added to isopropyl alcohol and titanium isopropoxide,
water was added slowly afterward, and the mixture was stirred. The composite formed
was calcined at 800 °C for 2 h in the flow of air for enhancing the TiO 2 crystallinity.
The prepared composite was characterized with XRD, TEM, and UV–Vis diffuse
reflectance spectrometer. The study suggested that the use of the prepared catalysts is helpful in hydrodesulfurization plants and Claus plant gas steams for the
simultaneous production of H 2 and removal of H 2 S [21, 22].
In an investigation, a titanium dioxide film-coated reactor was made via heat treatment and sol–gel process as the potential candidate for the photocatalytic degradation
of H 2 S. The prepared compound depicted excellent H 2 S degradation capability for
the generation of H 2. Tetrabutyl titanate was used as the precursor for the synthesis
the TiO 2 . Solution of tetrabutyl titanate was made in absolute ethanol followed by the
addition of a mixture containing distilled water, glacial acetic, and absolute ethanol.
This resulted in the formation of semi-transparent sol, which was allowed to age
for 7 days. A quartz pipe (cleaned with sulfuric acid, distilled water, and ultrasonication) was used as the base for the deposition of TiO 2 film. The prepared sol was
discharged into the quartz pipe (the pipe was wrapped with plastic from outside),
41
the product is allowed to grow on the pieces of blank glass at 425 °C–475 °C for
8 h. The increase in temperature caused the increase in the size of quantum dots of
CdS0.5Se0.5/CdSe as the growth is dependent on temperature because of nucleation
and growth mechanisms. XRD and Raman spectroscopic analysis of the sample
revealed that the CdS 0.5 Se 0.5 and CdSe are monodispersed in quantum dot-glass
nanosystem and have hexagonal structure. CdSe quantum dots have size in the range
of 2–12 nm. TEM and UV–Vis spectroscopy were used to determine the quantum
confinement of CdS 0.5 Se 0.5 and CdSe. The control of CdS 0.5 Se 0.5 quantum dot size
allowed the adjustment of bandgap from 3.6 eV to 1.8 eV. This improved the absorption of visible light, which resulted in the enhanced catalytic activity. 21 and 26%
apparent quantum yields of hydrogen liberation were achieved by using CdSe and
CdS 0.5 Se 0.5 quantum dot–glass nanosystems, respectively, for the decomposition of
H 2 S [20].
4.3 Titanium-Based Nanomaterials and Hydrogen Sulfide
Decomposition
Titanium-based photocatalyst is frequently used in the decomposition of H 2 S for
the generation of H 2 . In a study, a nanocomposite was fabricated with bulk CdS
and nanocrystalline TiO 2 as the photocatalyst for the generation of hydrogen from
aqueous solution of H 2 S under visible light of the solar spectrum. For the preparation
of the CdS, aqueous solution of Na 2 S was mixed with Cd (NO 3 ) 2 and further dissolved
in isopropyl alcohol. A precipitated product was obtained which was calcined at
800 °C for 1 h. The calcination was performed in helium atmosphere so as to enhance
the crystallinity of CdS. For the synthesis of CdS/TiO 2 bulk-nanocomposite photocatalyst, the prepared CdS was added to isopropyl alcohol and titanium isopropoxide,
water was added slowly afterward, and the mixture was stirred. The composite formed
was calcined at 800 °C for 2 h in the flow of air for enhancing the TiO 2 crystallinity.
The prepared composite was characterized with XRD, TEM, and UV–Vis diffuse
reflectance spectrometer. The study suggested that the use of the prepared catalysts is helpful in hydrodesulfurization plants and Claus plant gas steams for the
simultaneous production of H 2 and removal of H 2 S [21, 22].
In an investigation, a titanium dioxide film-coated reactor was made via heat treatment and sol–gel process as the potential candidate for the photocatalytic degradation
of H 2 S. The prepared compound depicted excellent H 2 S degradation capability for
the generation of H 2. Tetrabutyl titanate was used as the precursor for the synthesis
the TiO 2 . Solution of tetrabutyl titanate was made in absolute ethanol followed by the
addition of a mixture containing distilled water, glacial acetic, and absolute ethanol.
This resulted in the formation of semi-transparent sol, which was allowed to age
for 7 days. A quartz pipe (cleaned with sulfuric acid, distilled water, and ultrasonication) was used as the base for the deposition of TiO 2 film. The prepared sol was
discharged into the quartz pipe (the pipe was wrapped with plastic from outside),