Journal of Indian Association of Pediatric Surgeons, 2003
ABSTRACT: We have reviewed 130 patients of posterior urethral valves in a single center in Kolkat... more ABSTRACT: We have reviewed 130 patients of posterior urethral valves in a single center in Kolkata over the last 4 years. Primary endoscopic valve ablation was performed in 104 patients(80 percent). Diversion was required in 19 (14.6 percent) patients who were not fit for primary valve ablation. Four did not improve after valve ablation and required diversion. Three more cases were referred to us after vesicostomy done elsewhere. One neonate expired due to septicemia. In comparison to our earlier report, the rate of diversion in our center is steadily declining and more and more neonates are being treated by primary valve ablation.
The present work demonstrates the C–S cross-coupling reaction between aryl halides and thiols usi... more The present work demonstrates the C–S cross-coupling reaction between aryl halides and thiols using nickel nanoparticles (Ni NPs) supported on reduced graphene oxide (Ni/RGO) as a heterogeneous catalyst. It is observed that the uniformly dispersed Ni NPs supported on RGO could exhibit excellent catalytic activity in C–S cross-coupling reactions and the catalytic application is generalized with diverse coupling partners. Although the electron-rich planar RGO surface helps in stabilizing the agglomeration-free Ni NPs, the catalytic process is found to occur involving Ni(II) species and the recovered catalyst containing both Ni(0)/Ni(II) species is equally efficient in recycle runs. A correlation of loading of Ni species, size of NPs and the intermediate Ni-related heterostructures formed during the catalytic process has been established for the first time, and found to be best in the C–S cross-coupling reaction for Ni(0) and Ni(II) NPs of the average sizes 11–12 nm and 4 nm, respectiv...
Inherent properties of graphene can be experienced by integrating it with different nanomaterials... more Inherent properties of graphene can be experienced by integrating it with different nanomaterials to form unique composite materials. Decorating the surface of graphene sheets with nanoparticles (NPs) is one of the recent approaches taken up by scientists all over the world. This article describes a simple synthesis route to preparing stable Ni NP-reduced graphene oxide (Ni-RGO) composite material. The otherwise unstable bare Ni NPs are stabilized when embedded in the RGO sheets. This synthesized composite material has a potential application in the formic acid-induced reduction of highly toxic aqueous Cr(VI) at room temperature (25 °C). The reduction of dichromate using formic acid as a reducing agent is a well-known redox reaction. However, the rate of the reaction is very slow at room temperature, which can be enhanced very significantly in the presence of Ni-RGO by introducing an intermediate redox step with formic acid. The Ni-RGO composite material is an easy to prepare, cheap, stable, reusable material that has the potential to replace costly Pd NPs used in this context. Ni-RGO is also found to be very active in enhancing the rate of reduction of other metal ions in the presence of formic acid at room temperature.
The synthesis of a mesoporous gamma-Al2O3 nanorod/reduced graphene oxide (gamma-Al2O3NR/RGO) comp... more The synthesis of a mesoporous gamma-Al2O3 nanorod/reduced graphene oxide (gamma-Al2O3NR/RGO) composite with a higher surface area and thermal conductivity than unmodified gamma-Al2O3 has been accomplished, and these materials were characterized in detail. The composite was used successfully as a support for poly(ethylenimine) (PEI) to capture CO2 at high temperature. The PEI-modified composite (gamma-Al2O3NR/ RGO/PEI) showed an excellent CO2 adsorption from simulated flue gas at 75 degrees C and complete desorption at 100 degrees C with recyclability. The maximum CO2 adsorption capacity of this material was 200.6 mgg(PEI)(-1) (1.14 mmol CO(2)g(adsorbent)(-1)) with an amine efficiency of 0.22, which is higher than that of bare gamma-Al2O3/PEI. As a result of its high thermal conductivity, the overheating of the adsorbent during exothermic CO2 adsorption by PEI was restricted and as a result the thermal degradation of PEI was prevented. Accordingly, the adsorption capacity of gamma-Al...
The synthesis of a mesoporous g-Al2O3 nanorod/reduced graphene
oxide (g-Al2O3NR/RGO) composite wi... more The synthesis of a mesoporous g-Al2O3 nanorod/reduced graphene oxide (g-Al2O3NR/RGO) composite with a higher surface area and thermal conductivity than unmodified g-Al2O3 has been accomplished, and these materials were characterized in detail. The composite was used successfully as a support for poly(ethylenimine) (PEI) to capture CO2 at high temperature. The PEI-modified composite (g-Al2O3NR/ RGO/PEI) showed an excellent CO2 adsorption from simulated flue gas at 75 8C and complete desorption at 100 8C with recyclability. The maximum CO2 adsorption capacity of this material was 200.6 mggPEI 1 (1.14 mmol CO2gadsorbent 1) with an amine efficiency of 0.22, which is higher than that of bare g-Al2O3/PEI. As a result of its high thermal conductivity, the overheating of the adsorbent during exothermic CO2 adsorption by PEI was restricted and as a result the thermal degradation of PEI was prevented. Accordingly, the adsorption capacity of g-Al2O3NR/RGO/PEI does not deteriorate like that of bare g-Al2O3/PEI during repeated CO2 adsorption– desorption cycles.
Controlled carbonisation of P123 block-co-polymer in ethanol yielded micelle-protected carbon nan... more Controlled carbonisation of P123 block-co-polymer in ethanol yielded micelle-protected carbon nanodots (CNDs) at room temperature. A purified and concentrated CND solution (quantum yield 10%) was incorporated into the organically-modified SiO2 (ORMOSIL) sol for the fabrication of transparent fluorescent coatings of thickness [similar]3 μm on glass. These films are scratch resistant with a surface hardness value of 8H. The sol can also be useful as a fluorescent ink/paint. The films retained the pristine photophysical properties of CNDs.
Langmuir : the ACS journal of surfaces and colloids, Jan 22, 2015
Synthesis of Cu2O-amine functionalized graphite nanosheet (AFGNS) composite has been accomplished... more Synthesis of Cu2O-amine functionalized graphite nanosheet (AFGNS) composite has been accomplished at room temperature. In the first step, AFGNS is synthesized by wet chemical functionalization where the -NH2 groups formed on nanosheet surface helps to anchor the Cu2+ ions homogeneously through co‒ordinate bonds. Reduction of Cu2+ (3.4 x 10-2 mmol) in presence of NaBH4 (1.8 mmol) can be restricted to Cu+1 on AFGNS surface at room temperature. This leads to the formation of uniform Cu2O nanoparticles (NP) on AFGNS. The role played by the -NH2 groups in anchoring Cu2+ ions and followed by stabilizing the Cu2O NP on AFGNS was understood by controlled reactions in absence of -NH2 groups and without any graphitic support, respectively. The prepared Cu2O-AFGNS composite shows excellent catalytic activity towards degradation of an azo dye, methyl orange which is an environmental pollutant. The dye degradation proceeds with high rate constant value and the composite shows high stability and ...
Reduced graphene oxide (RGO) has emerged as an excellent 2D catalyst support. A high concentratio... more Reduced graphene oxide (RGO) has emerged as an excellent 2D catalyst support. A high concentration of air stable Ni(0) nanoparticles ($40 wt%) of average size 11 nm can be loaded on reduced graphene oxide. In this article Kumada–Corriu cross-coupling reactions have been studied extensively using RGO supported 40 wt% Ni nanoparticles (Ni/RGO-40) as a heterogeneous catalyst. The reaction conditions were optimized by performing the cross-coupling between 4-iodoanisole and phenylmagnesium chloride in the presence of a catalytic amount of Ni/RGO-40. A detailed study of the catalysis was performed by varying the haloarenes and Grignard reagents under the optimized conditions with yields of 91–72%. The products were characterized by 1 H and 13 C NMR spectroscopy. The catalyst was found to be significantly reusable. Finally the recovered Ni/RGO-40 was characterized by X-ray diffraction (XRD) and Raman spectroscopy and found to be unaffected. Considering the catalytic performance, reusability and economic reasons, Ni/RGO-40 can be of technological importance.
The fabrication of black and electrically conducting films on glass substrate derived from covale... more The fabrication of black and electrically conducting films on glass substrate derived from covalently functionalized reduced graphene oxide (FRGO) has been reported in this work. Graphene oxide (GO) was first prepared following the Hummers method and then functionalized using an organically modified silicon alkoxide, 3-glycidoxypropyltrimethoxysilane (GLYMO) in an ordered fashion. Catalyst (aluminium acetylacetonate) induced selective polymerization of the epoxy groups of GO and GLYMO was found to occur via the formation of ethereal (–C–O–C–) linkages. The formation of such linkages was confirmed by IR, Raman, TGA, X-Ray diffraction and TEM studies. Finally the functionalized graphene oxide (FGO) films were subjected to thermal reduction in an inert (N2) atmosphere to obtain FRGO films. These hard FRGO films are electrically conducting and appeared as black coatings on glass. By varying the loading (20–30 wt%) of GO with the covalently bonded organically modified silica, the sheet resistance values can be tuned in a linear way from 0.8 106 to 1.4 103 U ,1. The uniform current–voltage (I–V) characteristics of the films can be nicely correlated with the sheet resistance values.
Inherent properties of graphene can be experienced
by integrating it with different nanomaterial... more Inherent properties of graphene can be experienced
by integrating it with different nanomaterials to form unique
composite materials. Decorating the surface of graphene sheets with nanoparticles (NPs) is one of the recent approaches taken up by scientists all over the world. This article describes a simple synthesis route to preparing stable Ni NP−reduced graphene oxide (Ni−RGO) composite material. The otherwise unstable bare Ni NPs are stabilized when embedded in the RGO sheets. This synthesized composite material has a potential application in the formic acid-induced reduction of highly toxic aqueous Cr(VI) at room temperature (25 °C). The reduction of dichromate using formic acid as a reducing agent is a well-known redox reaction. However, the rate of the reaction is very slow at room temperature, which can be enhanced very significantly in the presence of Ni−RGO by introducing an intermediate redox step with formic acid. The Ni−RGO composite material is an easy to prepare, cheap, stable, reusable material that has the potential to replace costly Pd NPs used in this context. Ni−RGO is also found to be very active in enhancing the rate of reduction of other metal ions in the presence of formic acid at room temperature.
Journal of Indian Association of Pediatric Surgeons, 2003
ABSTRACT: We have reviewed 130 patients of posterior urethral valves in a single center in Kolkat... more ABSTRACT: We have reviewed 130 patients of posterior urethral valves in a single center in Kolkata over the last 4 years. Primary endoscopic valve ablation was performed in 104 patients(80 percent). Diversion was required in 19 (14.6 percent) patients who were not fit for primary valve ablation. Four did not improve after valve ablation and required diversion. Three more cases were referred to us after vesicostomy done elsewhere. One neonate expired due to septicemia. In comparison to our earlier report, the rate of diversion in our center is steadily declining and more and more neonates are being treated by primary valve ablation.
The present work demonstrates the C–S cross-coupling reaction between aryl halides and thiols usi... more The present work demonstrates the C–S cross-coupling reaction between aryl halides and thiols using nickel nanoparticles (Ni NPs) supported on reduced graphene oxide (Ni/RGO) as a heterogeneous catalyst. It is observed that the uniformly dispersed Ni NPs supported on RGO could exhibit excellent catalytic activity in C–S cross-coupling reactions and the catalytic application is generalized with diverse coupling partners. Although the electron-rich planar RGO surface helps in stabilizing the agglomeration-free Ni NPs, the catalytic process is found to occur involving Ni(II) species and the recovered catalyst containing both Ni(0)/Ni(II) species is equally efficient in recycle runs. A correlation of loading of Ni species, size of NPs and the intermediate Ni-related heterostructures formed during the catalytic process has been established for the first time, and found to be best in the C–S cross-coupling reaction for Ni(0) and Ni(II) NPs of the average sizes 11–12 nm and 4 nm, respectiv...
Inherent properties of graphene can be experienced by integrating it with different nanomaterials... more Inherent properties of graphene can be experienced by integrating it with different nanomaterials to form unique composite materials. Decorating the surface of graphene sheets with nanoparticles (NPs) is one of the recent approaches taken up by scientists all over the world. This article describes a simple synthesis route to preparing stable Ni NP-reduced graphene oxide (Ni-RGO) composite material. The otherwise unstable bare Ni NPs are stabilized when embedded in the RGO sheets. This synthesized composite material has a potential application in the formic acid-induced reduction of highly toxic aqueous Cr(VI) at room temperature (25 °C). The reduction of dichromate using formic acid as a reducing agent is a well-known redox reaction. However, the rate of the reaction is very slow at room temperature, which can be enhanced very significantly in the presence of Ni-RGO by introducing an intermediate redox step with formic acid. The Ni-RGO composite material is an easy to prepare, cheap, stable, reusable material that has the potential to replace costly Pd NPs used in this context. Ni-RGO is also found to be very active in enhancing the rate of reduction of other metal ions in the presence of formic acid at room temperature.
The synthesis of a mesoporous gamma-Al2O3 nanorod/reduced graphene oxide (gamma-Al2O3NR/RGO) comp... more The synthesis of a mesoporous gamma-Al2O3 nanorod/reduced graphene oxide (gamma-Al2O3NR/RGO) composite with a higher surface area and thermal conductivity than unmodified gamma-Al2O3 has been accomplished, and these materials were characterized in detail. The composite was used successfully as a support for poly(ethylenimine) (PEI) to capture CO2 at high temperature. The PEI-modified composite (gamma-Al2O3NR/ RGO/PEI) showed an excellent CO2 adsorption from simulated flue gas at 75 degrees C and complete desorption at 100 degrees C with recyclability. The maximum CO2 adsorption capacity of this material was 200.6 mgg(PEI)(-1) (1.14 mmol CO(2)g(adsorbent)(-1)) with an amine efficiency of 0.22, which is higher than that of bare gamma-Al2O3/PEI. As a result of its high thermal conductivity, the overheating of the adsorbent during exothermic CO2 adsorption by PEI was restricted and as a result the thermal degradation of PEI was prevented. Accordingly, the adsorption capacity of gamma-Al...
The synthesis of a mesoporous g-Al2O3 nanorod/reduced graphene
oxide (g-Al2O3NR/RGO) composite wi... more The synthesis of a mesoporous g-Al2O3 nanorod/reduced graphene oxide (g-Al2O3NR/RGO) composite with a higher surface area and thermal conductivity than unmodified g-Al2O3 has been accomplished, and these materials were characterized in detail. The composite was used successfully as a support for poly(ethylenimine) (PEI) to capture CO2 at high temperature. The PEI-modified composite (g-Al2O3NR/ RGO/PEI) showed an excellent CO2 adsorption from simulated flue gas at 75 8C and complete desorption at 100 8C with recyclability. The maximum CO2 adsorption capacity of this material was 200.6 mggPEI 1 (1.14 mmol CO2gadsorbent 1) with an amine efficiency of 0.22, which is higher than that of bare g-Al2O3/PEI. As a result of its high thermal conductivity, the overheating of the adsorbent during exothermic CO2 adsorption by PEI was restricted and as a result the thermal degradation of PEI was prevented. Accordingly, the adsorption capacity of g-Al2O3NR/RGO/PEI does not deteriorate like that of bare g-Al2O3/PEI during repeated CO2 adsorption– desorption cycles.
Controlled carbonisation of P123 block-co-polymer in ethanol yielded micelle-protected carbon nan... more Controlled carbonisation of P123 block-co-polymer in ethanol yielded micelle-protected carbon nanodots (CNDs) at room temperature. A purified and concentrated CND solution (quantum yield 10%) was incorporated into the organically-modified SiO2 (ORMOSIL) sol for the fabrication of transparent fluorescent coatings of thickness [similar]3 μm on glass. These films are scratch resistant with a surface hardness value of 8H. The sol can also be useful as a fluorescent ink/paint. The films retained the pristine photophysical properties of CNDs.
Langmuir : the ACS journal of surfaces and colloids, Jan 22, 2015
Synthesis of Cu2O-amine functionalized graphite nanosheet (AFGNS) composite has been accomplished... more Synthesis of Cu2O-amine functionalized graphite nanosheet (AFGNS) composite has been accomplished at room temperature. In the first step, AFGNS is synthesized by wet chemical functionalization where the -NH2 groups formed on nanosheet surface helps to anchor the Cu2+ ions homogeneously through co‒ordinate bonds. Reduction of Cu2+ (3.4 x 10-2 mmol) in presence of NaBH4 (1.8 mmol) can be restricted to Cu+1 on AFGNS surface at room temperature. This leads to the formation of uniform Cu2O nanoparticles (NP) on AFGNS. The role played by the -NH2 groups in anchoring Cu2+ ions and followed by stabilizing the Cu2O NP on AFGNS was understood by controlled reactions in absence of -NH2 groups and without any graphitic support, respectively. The prepared Cu2O-AFGNS composite shows excellent catalytic activity towards degradation of an azo dye, methyl orange which is an environmental pollutant. The dye degradation proceeds with high rate constant value and the composite shows high stability and ...
Reduced graphene oxide (RGO) has emerged as an excellent 2D catalyst support. A high concentratio... more Reduced graphene oxide (RGO) has emerged as an excellent 2D catalyst support. A high concentration of air stable Ni(0) nanoparticles ($40 wt%) of average size 11 nm can be loaded on reduced graphene oxide. In this article Kumada–Corriu cross-coupling reactions have been studied extensively using RGO supported 40 wt% Ni nanoparticles (Ni/RGO-40) as a heterogeneous catalyst. The reaction conditions were optimized by performing the cross-coupling between 4-iodoanisole and phenylmagnesium chloride in the presence of a catalytic amount of Ni/RGO-40. A detailed study of the catalysis was performed by varying the haloarenes and Grignard reagents under the optimized conditions with yields of 91–72%. The products were characterized by 1 H and 13 C NMR spectroscopy. The catalyst was found to be significantly reusable. Finally the recovered Ni/RGO-40 was characterized by X-ray diffraction (XRD) and Raman spectroscopy and found to be unaffected. Considering the catalytic performance, reusability and economic reasons, Ni/RGO-40 can be of technological importance.
The fabrication of black and electrically conducting films on glass substrate derived from covale... more The fabrication of black and electrically conducting films on glass substrate derived from covalently functionalized reduced graphene oxide (FRGO) has been reported in this work. Graphene oxide (GO) was first prepared following the Hummers method and then functionalized using an organically modified silicon alkoxide, 3-glycidoxypropyltrimethoxysilane (GLYMO) in an ordered fashion. Catalyst (aluminium acetylacetonate) induced selective polymerization of the epoxy groups of GO and GLYMO was found to occur via the formation of ethereal (–C–O–C–) linkages. The formation of such linkages was confirmed by IR, Raman, TGA, X-Ray diffraction and TEM studies. Finally the functionalized graphene oxide (FGO) films were subjected to thermal reduction in an inert (N2) atmosphere to obtain FRGO films. These hard FRGO films are electrically conducting and appeared as black coatings on glass. By varying the loading (20–30 wt%) of GO with the covalently bonded organically modified silica, the sheet resistance values can be tuned in a linear way from 0.8 106 to 1.4 103 U ,1. The uniform current–voltage (I–V) characteristics of the films can be nicely correlated with the sheet resistance values.
Inherent properties of graphene can be experienced
by integrating it with different nanomaterial... more Inherent properties of graphene can be experienced
by integrating it with different nanomaterials to form unique
composite materials. Decorating the surface of graphene sheets with nanoparticles (NPs) is one of the recent approaches taken up by scientists all over the world. This article describes a simple synthesis route to preparing stable Ni NP−reduced graphene oxide (Ni−RGO) composite material. The otherwise unstable bare Ni NPs are stabilized when embedded in the RGO sheets. This synthesized composite material has a potential application in the formic acid-induced reduction of highly toxic aqueous Cr(VI) at room temperature (25 °C). The reduction of dichromate using formic acid as a reducing agent is a well-known redox reaction. However, the rate of the reaction is very slow at room temperature, which can be enhanced very significantly in the presence of Ni−RGO by introducing an intermediate redox step with formic acid. The Ni−RGO composite material is an easy to prepare, cheap, stable, reusable material that has the potential to replace costly Pd NPs used in this context. Ni−RGO is also found to be very active in enhancing the rate of reduction of other metal ions in the presence of formic acid at room temperature.
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oxide (g-Al2O3NR/RGO) composite with a higher surface
area and thermal conductivity than unmodified g-Al2O3
has been accomplished, and these materials were characterized
in detail. The composite was used successfully as a support
for poly(ethylenimine) (PEI) to capture CO2 at high
temperature. The PEI-modified composite (g-Al2O3NR/
RGO/PEI) showed an excellent CO2 adsorption from simulated
flue gas at 75 8C and complete desorption at 100 8C
with recyclability. The maximum CO2 adsorption capacity of
this material was 200.6 mggPEI
1 (1.14 mmol CO2gadsorbent
1)
with an amine efficiency of 0.22, which is higher than that of
bare g-Al2O3/PEI. As a result of its high thermal conductivity,
the overheating of the adsorbent during exothermic CO2
adsorption by PEI was restricted and as a result the thermal
degradation of PEI was prevented. Accordingly, the adsorption
capacity of g-Al2O3NR/RGO/PEI does not deteriorate
like that of bare g-Al2O3/PEI during repeated CO2 adsorption–
desorption cycles.
functionalized reduced graphene oxide (FRGO) has been reported in this work. Graphene oxide (GO)
was first prepared following the Hummers method and then functionalized using an organically
modified silicon alkoxide, 3-glycidoxypropyltrimethoxysilane (GLYMO) in an ordered fashion.
Catalyst (aluminium acetylacetonate) induced selective polymerization of the epoxy groups of GO and
GLYMO was found to occur via the formation of ethereal (–C–O–C–) linkages. The formation of such
linkages was confirmed by IR, Raman, TGA, X-Ray diffraction and TEM studies. Finally the
functionalized graphene oxide (FGO) films were subjected to thermal reduction in an inert (N2)
atmosphere to obtain FRGO films. These hard FRGO films are electrically conducting and appeared as
black coatings on glass. By varying the loading (20–30 wt%) of GO with the covalently bonded
organically modified silica, the sheet resistance values can be tuned in a linear way from 0.8 106 to
1.4 103 U ,1. The uniform current–voltage (I–V) characteristics of the films can be nicely
correlated with the sheet resistance values.
by integrating it with different nanomaterials to form unique
composite materials. Decorating the surface of graphene sheets with nanoparticles (NPs) is one of the recent approaches taken up by scientists all over the world. This article describes a simple synthesis route to preparing stable Ni NP−reduced graphene oxide (Ni−RGO) composite material. The otherwise unstable bare Ni NPs are stabilized when embedded in the RGO sheets. This synthesized composite material has a potential application in the formic acid-induced reduction of highly toxic aqueous Cr(VI) at room temperature (25 °C). The reduction of dichromate using formic acid as a reducing agent is a well-known redox reaction. However, the rate of the reaction is very slow at room temperature, which can be enhanced very significantly in the presence of Ni−RGO by introducing an intermediate redox step with formic acid. The Ni−RGO composite material is an easy to prepare, cheap, stable, reusable material that has the potential to replace costly Pd NPs used in this context. Ni−RGO is also found to be very active in enhancing the rate of reduction of other metal ions in the presence of formic acid at room temperature.
oxide (g-Al2O3NR/RGO) composite with a higher surface
area and thermal conductivity than unmodified g-Al2O3
has been accomplished, and these materials were characterized
in detail. The composite was used successfully as a support
for poly(ethylenimine) (PEI) to capture CO2 at high
temperature. The PEI-modified composite (g-Al2O3NR/
RGO/PEI) showed an excellent CO2 adsorption from simulated
flue gas at 75 8C and complete desorption at 100 8C
with recyclability. The maximum CO2 adsorption capacity of
this material was 200.6 mggPEI
1 (1.14 mmol CO2gadsorbent
1)
with an amine efficiency of 0.22, which is higher than that of
bare g-Al2O3/PEI. As a result of its high thermal conductivity,
the overheating of the adsorbent during exothermic CO2
adsorption by PEI was restricted and as a result the thermal
degradation of PEI was prevented. Accordingly, the adsorption
capacity of g-Al2O3NR/RGO/PEI does not deteriorate
like that of bare g-Al2O3/PEI during repeated CO2 adsorption–
desorption cycles.
functionalized reduced graphene oxide (FRGO) has been reported in this work. Graphene oxide (GO)
was first prepared following the Hummers method and then functionalized using an organically
modified silicon alkoxide, 3-glycidoxypropyltrimethoxysilane (GLYMO) in an ordered fashion.
Catalyst (aluminium acetylacetonate) induced selective polymerization of the epoxy groups of GO and
GLYMO was found to occur via the formation of ethereal (–C–O–C–) linkages. The formation of such
linkages was confirmed by IR, Raman, TGA, X-Ray diffraction and TEM studies. Finally the
functionalized graphene oxide (FGO) films were subjected to thermal reduction in an inert (N2)
atmosphere to obtain FRGO films. These hard FRGO films are electrically conducting and appeared as
black coatings on glass. By varying the loading (20–30 wt%) of GO with the covalently bonded
organically modified silica, the sheet resistance values can be tuned in a linear way from 0.8 106 to
1.4 103 U ,1. The uniform current–voltage (I–V) characteristics of the films can be nicely
correlated with the sheet resistance values.
by integrating it with different nanomaterials to form unique
composite materials. Decorating the surface of graphene sheets with nanoparticles (NPs) is one of the recent approaches taken up by scientists all over the world. This article describes a simple synthesis route to preparing stable Ni NP−reduced graphene oxide (Ni−RGO) composite material. The otherwise unstable bare Ni NPs are stabilized when embedded in the RGO sheets. This synthesized composite material has a potential application in the formic acid-induced reduction of highly toxic aqueous Cr(VI) at room temperature (25 °C). The reduction of dichromate using formic acid as a reducing agent is a well-known redox reaction. However, the rate of the reaction is very slow at room temperature, which can be enhanced very significantly in the presence of Ni−RGO by introducing an intermediate redox step with formic acid. The Ni−RGO composite material is an easy to prepare, cheap, stable, reusable material that has the potential to replace costly Pd NPs used in this context. Ni−RGO is also found to be very active in enhancing the rate of reduction of other metal ions in the presence of formic acid at room temperature.