94
5 Synthesis of Three-Dimensional Nanomaterials
rGO electrodes revealed an impressively high energy and power output. It is anticipated that the simple and facile method for fabricating 3D flower-like architecture
of NiMn LDH/rGO microspheres composite may shed light on the design of novel
hierarchical structure electrode materials for high-performance supercapacitors. In
Fig. 5.7b, a simple solvothermal method was used by Ngo et al. to hybridize Nickelmanganese spinel oxide (NiMn 2 O 4 ) and reduced graphene oxide hydrogel (rGOH),
and a highly porous 3D structure was fabricated (Ngo et al. 2017). NiMn 2 O 4 /rGOH
was fabricated using a facile one-step solvothermal method. Typically, 0.250 g of
Ni(OCOCH 3 ) 2 · 4H 2 O, 0.490 g of (CH 3 COO) 2 Mn · 4H 2 O, and 1.267 g of C 6 H 8 O 7
· H 2 O were dissolved in 10 mL of ethanol (C 2 H 5 OH) with vigorous stirring for
30 min. The resulting mixture was then added to 5 mL of an aqueous GO slurry with
a 5 mg mL
−1 solid content that was synthesized by Hummer’s method. Transferring
the mixture to a Teflon-lined stainless steel autoclave and holding at 160 °C for 12 h
to fabricate a porous 3D networked structure of NiMn 2 O 4 /rGOH.
An activated pyrene decorated graphene nanocomposite, applied as an electrode
material in supercapacitor, was synthesized via solvothermal followed by heating
method (reported by Li et al. 2018). A series of nanostructured pyrene/graphene
composites (PGCs) were prepared by controlling the mass of two kinds of materials
in the composite process. The reduced graphene oxide (rGO) was synthesized using
pervious literature report (Wu et al. 2015). Pyrene decorated graphene composites
were synthesized by solvothermal process and followed by activated process. As a
typical procedure, 25 mg of pyrene and 75 mg of GO were dropped into 75 mL
of ethanol and then sonication treatment for 30 min. When the mixed solution was
uniformly dispersed, the mixture was poured into a Teflon-lined stainless steel autoclave (50 mL in volume) for solvothermal reaction at 160 °C for 16 h. The suspension
was washed with ethanol by repeated centrifugation, and then dried in a vacuum oven
at 70 °C for 12 h to obtain the powders of pyrene/rGO (PGO 1/3 ). The PGO 1/3 was
then heated at 95 °C under argon flow for 2 h to activate pyrene-based composites.
The final product of pyrene/graphene composites was denoted as PGC 1/3 . This study
provides a new method and a way to learn from it for the study of graphene/organic
electrode materials.
Via a solvothermal route, mesoporous NiCo 2 S 4 nanoparticles were synthesized
as remarkable supercapacitor electrode materials by Zhu et al. (Li et al. 2018). In the
preparation of NiCo 2 S 4 , 0.195 mmol of Ni(AC) 2 · 4H 2 O and 0.39 mmol of Co(AC) 2
· 4H 2 O were dissolved in 40 mL of ethylene glycol and stirred for 30 min. Then,
1.17 mmol of thiourea was introduced into the mixed solution under stirring. After
stirring for another 30 min, the solution was transferred to a Teflon-lined stainless
steel autoclave and heated in an oven at 180 °C for 24 h. The black precipitate was
collected by centrifugation after being cooled to room temperature, then washed with
distilled water and ethanol several times, followed by drying at 60 °C for 24 h to
obtain the products.
5 Synthesis of Three-Dimensional Nanomaterials
rGO electrodes revealed an impressively high energy and power output. It is anticipated that the simple and facile method for fabricating 3D flower-like architecture
of NiMn LDH/rGO microspheres composite may shed light on the design of novel
hierarchical structure electrode materials for high-performance supercapacitors. In
Fig. 5.7b, a simple solvothermal method was used by Ngo et al. to hybridize Nickelmanganese spinel oxide (NiMn 2 O 4 ) and reduced graphene oxide hydrogel (rGOH),
and a highly porous 3D structure was fabricated (Ngo et al. 2017). NiMn 2 O 4 /rGOH
was fabricated using a facile one-step solvothermal method. Typically, 0.250 g of
Ni(OCOCH 3 ) 2 · 4H 2 O, 0.490 g of (CH 3 COO) 2 Mn · 4H 2 O, and 1.267 g of C 6 H 8 O 7
· H 2 O were dissolved in 10 mL of ethanol (C 2 H 5 OH) with vigorous stirring for
30 min. The resulting mixture was then added to 5 mL of an aqueous GO slurry with
a 5 mg mL
−1 solid content that was synthesized by Hummer’s method. Transferring
the mixture to a Teflon-lined stainless steel autoclave and holding at 160 °C for 12 h
to fabricate a porous 3D networked structure of NiMn 2 O 4 /rGOH.
An activated pyrene decorated graphene nanocomposite, applied as an electrode
material in supercapacitor, was synthesized via solvothermal followed by heating
method (reported by Li et al. 2018). A series of nanostructured pyrene/graphene
composites (PGCs) were prepared by controlling the mass of two kinds of materials
in the composite process. The reduced graphene oxide (rGO) was synthesized using
pervious literature report (Wu et al. 2015). Pyrene decorated graphene composites
were synthesized by solvothermal process and followed by activated process. As a
typical procedure, 25 mg of pyrene and 75 mg of GO were dropped into 75 mL
of ethanol and then sonication treatment for 30 min. When the mixed solution was
uniformly dispersed, the mixture was poured into a Teflon-lined stainless steel autoclave (50 mL in volume) for solvothermal reaction at 160 °C for 16 h. The suspension
was washed with ethanol by repeated centrifugation, and then dried in a vacuum oven
at 70 °C for 12 h to obtain the powders of pyrene/rGO (PGO 1/3 ). The PGO 1/3 was
then heated at 95 °C under argon flow for 2 h to activate pyrene-based composites.
The final product of pyrene/graphene composites was denoted as PGC 1/3 . This study
provides a new method and a way to learn from it for the study of graphene/organic
electrode materials.
Via a solvothermal route, mesoporous NiCo 2 S 4 nanoparticles were synthesized
as remarkable supercapacitor electrode materials by Zhu et al. (Li et al. 2018). In the
preparation of NiCo 2 S 4 , 0.195 mmol of Ni(AC) 2 · 4H 2 O and 0.39 mmol of Co(AC) 2
· 4H 2 O were dissolved in 40 mL of ethylene glycol and stirred for 30 min. Then,
1.17 mmol of thiourea was introduced into the mixed solution under stirring. After
stirring for another 30 min, the solution was transferred to a Teflon-lined stainless
steel autoclave and heated in an oven at 180 °C for 24 h. The black precipitate was
collected by centrifugation after being cooled to room temperature, then washed with
distilled water and ethanol several times, followed by drying at 60 °C for 24 h to
obtain the products.