2.4 Nanotubes and Water Splitting Reactions
19
at room temperature with continued stirring for a day. Later on, 2-mercaptoethanol
was added to the mixture and was stirred for half a day. The carbonization of this
mixture in N 2 atmosphere resulted in the formation of N, S-CNT [19].
A study has determined that p-type Zn-doped α-Fe 2 O 3 nanotube formed on a
transparent conductive has excellent photoelectrochemical abilities and assists the
overall water splitting reaction. For developing these nanotubes, ZnO nanorod arrays
on FTO-coated glass sacrificial templates and Zn sources were used, and FeCl 2
aqueous solution was employed as the electrolyte. Afterward, anodic potential of 1 V
was applied on the ZnO nanorods for so as to assist the oxidation of ferrous to ferric
subsequently leading to the precipitation of the Fe
3+ as amorphous γ-FeOOH on ZnO
nanorod surface. Some of the dissolved Zn ions were deposited on γ-FeOOH and
were later on annealed for 120 min in N 2 atmosphere in order to convert γ -FeOOH
into α-Fe 2 O 3 nanotubes [20].
In an investigation, 1D-1D metal-free multiwalled carbon nanotubes
(MWCNT)/SiC nanowires were fabricated via an in situ chemical mechanism
between silicon powder and MWCNTs. These nanoheterostructures were grown via
vapor–liquid–solid (VLS) mechanism. The (MWCNT)/SiC nanotubes were characterized for their structure, composition, and morphology by XRD, TEM, thermal
gravimetric analysis (TGA), and UV–Vis analysis. In the study, the photoactivities of
the prepared nanostructures were also determined for the evolution of H 2 . The results
depicted better activity of metal-free MWCNTs/SiC 1D-1D nanoheterostructures as
compared to the simple SiC nanowires in visible light irradiation. The high-efficiency
MWCNTs/SiC in liberation of H 2 from water splitting is attributed to its promising
separation of photogenerated electron–hole pair, improved visible light absorption,
enhanced crystallinity, and distinctive 1D-1D nanoheterostructures [21].
A study reported camphor sulfonic acid doped polyaniline-WO 3 (CSPA-WO 3 )
nanocomposites modified with reduced graphene oxide (rGO). The CSPA-WO 3 was
able to reduce GO to rGO photoelectrochemically due to its semi-conductive nature.
The morphology, chemical composition, and structure of CSPA-WO 3 -rGO were
characterized by X-ray photoelectron spectroscopy (XPS), XRD, Fourier transform
infrared (FTIR) spectroscopy, Raman spectroscopy, field-emission scanning electron
microscopy (FESEM), and TEM. The influence of rGO addition on the solar. CSPAWO 3 depicted remarkable photoelectrochemical current density and photoconversion efficiency visible light illumination. For the fabrication of these nanostructures,
a suspension of WO 3 nanoparticles and camphor sulfonic acid was made in distilled
water. Afterward, distilled aniline was added at 4 °C with continuous stirring. Later
on, an oxidizing agent (ammonium persulfate) was slowly added and the prepared
CSPA-WO 3 was filtered and washed with water. GO was prepared with modified
Hummer’s method. For the preparation of CSPA-WO 3 -rGO, CSPA-WO 3 and rGO
were sonicated separately in water afterward both suspensions were stirred together
in a homogenized mixture and were later irradiated by a 300 W Xenon for 60 min
while stirring slowly. The material thus obtained was washed and dried at 60 °C [22].
19
at room temperature with continued stirring for a day. Later on, 2-mercaptoethanol
was added to the mixture and was stirred for half a day. The carbonization of this
mixture in N 2 atmosphere resulted in the formation of N, S-CNT [19].
A study has determined that p-type Zn-doped α-Fe 2 O 3 nanotube formed on a
transparent conductive has excellent photoelectrochemical abilities and assists the
overall water splitting reaction. For developing these nanotubes, ZnO nanorod arrays
on FTO-coated glass sacrificial templates and Zn sources were used, and FeCl 2
aqueous solution was employed as the electrolyte. Afterward, anodic potential of 1 V
was applied on the ZnO nanorods for so as to assist the oxidation of ferrous to ferric
subsequently leading to the precipitation of the Fe
3+ as amorphous γ-FeOOH on ZnO
nanorod surface. Some of the dissolved Zn ions were deposited on γ-FeOOH and
were later on annealed for 120 min in N 2 atmosphere in order to convert γ -FeOOH
into α-Fe 2 O 3 nanotubes [20].
In an investigation, 1D-1D metal-free multiwalled carbon nanotubes
(MWCNT)/SiC nanowires were fabricated via an in situ chemical mechanism
between silicon powder and MWCNTs. These nanoheterostructures were grown via
vapor–liquid–solid (VLS) mechanism. The (MWCNT)/SiC nanotubes were characterized for their structure, composition, and morphology by XRD, TEM, thermal
gravimetric analysis (TGA), and UV–Vis analysis. In the study, the photoactivities of
the prepared nanostructures were also determined for the evolution of H 2 . The results
depicted better activity of metal-free MWCNTs/SiC 1D-1D nanoheterostructures as
compared to the simple SiC nanowires in visible light irradiation. The high-efficiency
MWCNTs/SiC in liberation of H 2 from water splitting is attributed to its promising
separation of photogenerated electron–hole pair, improved visible light absorption,
enhanced crystallinity, and distinctive 1D-1D nanoheterostructures [21].
A study reported camphor sulfonic acid doped polyaniline-WO 3 (CSPA-WO 3 )
nanocomposites modified with reduced graphene oxide (rGO). The CSPA-WO 3 was
able to reduce GO to rGO photoelectrochemically due to its semi-conductive nature.
The morphology, chemical composition, and structure of CSPA-WO 3 -rGO were
characterized by X-ray photoelectron spectroscopy (XPS), XRD, Fourier transform
infrared (FTIR) spectroscopy, Raman spectroscopy, field-emission scanning electron
microscopy (FESEM), and TEM. The influence of rGO addition on the solar. CSPAWO 3 depicted remarkable photoelectrochemical current density and photoconversion efficiency visible light illumination. For the fabrication of these nanostructures,
a suspension of WO 3 nanoparticles and camphor sulfonic acid was made in distilled
water. Afterward, distilled aniline was added at 4 °C with continuous stirring. Later
on, an oxidizing agent (ammonium persulfate) was slowly added and the prepared
CSPA-WO 3 was filtered and washed with water. GO was prepared with modified
Hummer’s method. For the preparation of CSPA-WO 3 -rGO, CSPA-WO 3 and rGO
were sonicated separately in water afterward both suspensions were stirred together
in a homogenized mixture and were later irradiated by a 300 W Xenon for 60 min
while stirring slowly. The material thus obtained was washed and dried at 60 °C [22].