20
2 Water Splitting Reactions and Nanotechnology
2.5 Nanosheets and Water Splitting Reactions
Nanosheets are also proven to be very effective in water splitting reactions. In a
study conducted by Zhou. et al. SiC ultrathin nanosheets covered with GO have been
reported. The sheets were prepared by vapor–solid mechanism. These nanosheets
have shown promising photocatalytic activities as assessed by HER from pure water
and water containing Na2S.SiC/GO nanosheets showed 10 times better photocatalytic activity in H 2 generation as compared to the SiC nanocrystals. The improved
photocatalytic of the nanosheets is related to the two-dimensional structure of
nanosheet, large surface area, improved visible light absorption, and fast SiC-tographene interfacial charge transfer. For the fabrication of these sheets, graphene
sheets were mixed with Si powder and were placed inside the tube furnace and
heated up to 1320 °C in Ar atmosphere. In the end, the excess Si was removed by
treating them with the mixture of HNO 3 and HF and dried at 100 °C. The nanosheets
were characterized by XRD, UV–Vis spectroscopy, Raman spectroscopy, TEM, etc.
[23].
Semiconductors of tantalate are promising photocatalysts for liberation of
hydrogen by photocatalytic splitting of water, as their conduction band involves
5d orbital, which has greater negative as compared to the H + /H 2 half reaction.
Bi 3 TaO 7 is a stable tantalate, having appropriate bandgap for visible light illumination under acidic or alkaline conditions. Nanosheets made of Bi 3 TaO 7 are found to
be significant for hydrogen generation from splitting of water. They are prepared by
mixing the ethanol suspensions of Bi (NO 3 ) 3 ·5H 2 O and TaCl 5 . Afterward, the pH of
the solution was adjusted aqueous solution of KOH. Later on, the mixture was placed
in Teflon-lined stainless-steel autoclave for a day at 180 °C. In the end, the Bi 3 TaO 7
nanoparticles were obtained, they were cooled at room temperature and washed with
water. Bi 3 TaO 7 nanosheet was generated by the liquid exfoliation process. For this
purpose, suspension of Bi(NO 3 ) 3 · 5H 2 O nanoparticles was made in distilled water
having sodium dodecyl sulfate (SDS) as the surfactant. The non-polar hydrocarbon
tail of the SDS combined with the surface of the nanosheet and the polar head of
SDS combined with the water lead to the formation of steric repulsion-resistant
nanosheets. Later on, the sheets were sonicated and centrifuged. These nanosheets
were characterized with XRD, Raman spectroscopy, SEM, and EDS. Nanoparticles
of Bi 3 TaO 7 depicted no hydrogen liberation; however, Bi 3 TaO 7 nanosheets showed
∼2.1 μ mol/h liberation of hydrogen in water splitting reaction [24].
In a study, nanosheets of Ni and rGO were prepared for photothermal effectdriven water splitting reaction. The hydrogen and oxygen liberation from the water
was studied simultaneously by the use of Ni/rGO nanosheets. Over the nanosheets
of Ni/rGO, under the illumination of visible light, both hydrogen and oxygen liberations were increased promisingly as the overpotential reduced to 49 and 50 mV
at 10 mA cm
−2 , respectively. The rGO absorbed incident irradiation for improving
the conductivity of electrocatalyst and heating the supported active entity (i.e Ni).
The hot active entity can enable the thermodynamics and kinetics of electrocatalytic
2 Water Splitting Reactions and Nanotechnology
2.5 Nanosheets and Water Splitting Reactions
Nanosheets are also proven to be very effective in water splitting reactions. In a
study conducted by Zhou. et al. SiC ultrathin nanosheets covered with GO have been
reported. The sheets were prepared by vapor–solid mechanism. These nanosheets
have shown promising photocatalytic activities as assessed by HER from pure water
and water containing Na2S.SiC/GO nanosheets showed 10 times better photocatalytic activity in H 2 generation as compared to the SiC nanocrystals. The improved
photocatalytic of the nanosheets is related to the two-dimensional structure of
nanosheet, large surface area, improved visible light absorption, and fast SiC-tographene interfacial charge transfer. For the fabrication of these sheets, graphene
sheets were mixed with Si powder and were placed inside the tube furnace and
heated up to 1320 °C in Ar atmosphere. In the end, the excess Si was removed by
treating them with the mixture of HNO 3 and HF and dried at 100 °C. The nanosheets
were characterized by XRD, UV–Vis spectroscopy, Raman spectroscopy, TEM, etc.
[23].
Semiconductors of tantalate are promising photocatalysts for liberation of
hydrogen by photocatalytic splitting of water, as their conduction band involves
5d orbital, which has greater negative as compared to the H + /H 2 half reaction.
Bi 3 TaO 7 is a stable tantalate, having appropriate bandgap for visible light illumination under acidic or alkaline conditions. Nanosheets made of Bi 3 TaO 7 are found to
be significant for hydrogen generation from splitting of water. They are prepared by
mixing the ethanol suspensions of Bi (NO 3 ) 3 ·5H 2 O and TaCl 5 . Afterward, the pH of
the solution was adjusted aqueous solution of KOH. Later on, the mixture was placed
in Teflon-lined stainless-steel autoclave for a day at 180 °C. In the end, the Bi 3 TaO 7
nanoparticles were obtained, they were cooled at room temperature and washed with
water. Bi 3 TaO 7 nanosheet was generated by the liquid exfoliation process. For this
purpose, suspension of Bi(NO 3 ) 3 · 5H 2 O nanoparticles was made in distilled water
having sodium dodecyl sulfate (SDS) as the surfactant. The non-polar hydrocarbon
tail of the SDS combined with the surface of the nanosheet and the polar head of
SDS combined with the water lead to the formation of steric repulsion-resistant
nanosheets. Later on, the sheets were sonicated and centrifuged. These nanosheets
were characterized with XRD, Raman spectroscopy, SEM, and EDS. Nanoparticles
of Bi 3 TaO 7 depicted no hydrogen liberation; however, Bi 3 TaO 7 nanosheets showed
∼2.1 μ mol/h liberation of hydrogen in water splitting reaction [24].
In a study, nanosheets of Ni and rGO were prepared for photothermal effectdriven water splitting reaction. The hydrogen and oxygen liberation from the water
was studied simultaneously by the use of Ni/rGO nanosheets. Over the nanosheets
of Ni/rGO, under the illumination of visible light, both hydrogen and oxygen liberations were increased promisingly as the overpotential reduced to 49 and 50 mV
at 10 mA cm
−2 , respectively. The rGO absorbed incident irradiation for improving
the conductivity of electrocatalyst and heating the supported active entity (i.e Ni).
The hot active entity can enable the thermodynamics and kinetics of electrocatalytic