Counter electrode (CE) is one of the major component which determine the energy conversion efficiency of the dye-sensitized solar cells (DSSCs). Here in, five types of CEs using two different ...materials were fabricated. Three types are zinc oxide (ZnO) based while other two are multi-walled carbon nanotubes based CEs. The thickness and resistance per cm2 of each CE were measured. The gel polymer electrolyte based on polyacrylonitrile polymer, sodium iodide salt, 1-Hexyl-3-methyl-imidazolium iodide ionic liquid was also prepared. The conductivity studies revealed that the highest ionic conductivity of gel polymer electrolyte was 6.72 mS cm−1 upon incorporation of 100 wt% 1-Hexyl-3-methyl-imidazolium iodide ionic liquid. This gel polymer electrolyte was sandwiched between commercial TiO2 photo-anode and different types of CE to fabricate the DSSCs. The J-V characteristic curves of the DSSCs were obtained and the DSSC characterization parameters were determined. The efficiencies achieved using ZnO and MWCNT-based CEs were ranging from 0.46% to 7.07%. The results demonstrate that ZnO and multi-walled carbon nanotubes are good candidates of CEs for DSSC application.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•A bifunctional electrode material, MWCNTs-ZrO2-Co3O4 is synthesized and characterized.•Using MWCNTs-ZrO2-Co3O4, an asymmetric supercapacitor is fabricated (MWCNTs-ZrO2-Co3O4//AC).•This device ...exhibits long-term cyclic stability and high specific energy.•Electrocatalytic reduction of CO2 selectively to HCOOH is achieved using MWCNTs-ZrO2-Co3O4.
In the field of renewable energy research, the development of materials for use as highly efficient supercapacitors and designing electrocatalytic materials for the reduction of CO2 to produce useful chemicals are envisaged as two important sustainable routes. However, developing stable, selective, and efficient materials for these purposes is a highly challenging task requiring numerous design attempts. In this work, cobalt oxide decorated zirconium oxide immobilized multiwalled carbon nanotubes (MWCNTs-ZrO2-Co3O4) is reported as a catalyst and battery electrode material for the electrochemical reduction of CO2 and supercapacitor applications, respectively. The MWCNTs-ZrO2-Co3O4 electrode assembled for the supercapacitor shows a specific capacity of 258.9 C/g at a current density of 1.0 A/g. The MWCNTs-ZrO2-Co3O4 and activated carbon (AC) based asymmetric supercapacitor (MWCNTs-ZrO2-Co3O4//AC) displays specific energy in the range of 8.9 Wh/kg (at 837.2 W/kg) to 6.23 Wh/kg (at 1674.4 W/kg). The device, MWCNTs-ZrO2-Co3O4//AC displays high cycling stability with 97% capacity retention after 7000 cycles at a current density of 1.0 A/g. In the electrocatalytic reduction of CO2, the MWCNTs-ZrO2-Co3O4 scaffold produces selectively formic acid during the electrolysis at -1.1 V (vs. Ag/AgCl) in 0.1 M aqueous KCl solution. These results indicate that MWCNTs-ZrO2-Co3O4 can serve as a bifunctional material.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The performance of dye-sensitized solar cells (DSSCs) depends on the ionic conductivity and flexibility of electrolyte. Gel polymer electrolytes (GPEs) consisting poly(propylene) carbonate (PPC) ...incorporated with double salts (i.e. calcium iodide (CaI
2
) and tetrabutylammonium iodide (TBAI)) were prepared. X-ray diffraction (XRD) authenticated that the crystallinity of PPC is mitigated after incorporation of different concentrations of CaI
2
and TBAI, which is favourable for ion transportation. Fourier-transform infrared spectroscopy (FTIR) unveils the occurrence of complexation between PPC and the double salts. GPE containing 10% of CaI
2
and 30% of TBAI exhibits the highest ionic conductivity (1.838 mS cm
−1
) with the activation energy of 0.156 eV. The fabricated DSSC employing the optimized GPE exhibits the energy conversion efficiency (η) of 5.49%, short circuit current density (
J
sc
) of 16.6 mA cm
−2
, open circuit voltage (
V
oc
) of 0.568 V and fill factor (FF) of 54%.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Neutron irradiation is one of the methods to improve the transport properties of superconductors by creating defects for flux pinning centers. In this work, the effects of fast neutron irradiation on ...(Bi
1.6
Pb
0.4
)Sr
2
Ca
2
Cu
3
O
10
(Bi-2223) superconductor were studied. The samples were prepared using the co-precipitation technique and were exposed to fast neutron irradiation via pneumatic transfer system (PTS) with a neutron flux of 2.5 × 10
12
n cm
−2
s
−1
from 60 to 660 s which are equivalent to neutron fluences of 1.55 × 10
14
to 1.70 × 10
15
n cm
−2
. The non-irradiated sample was dominantly Bi-2223 phase (85%) as shown by X-ray diffraction patterns. However, after irradiation, the volume fraction of the Bi-2223 was reduced and the (Bi
1.6
Pb
0.4
)Sr
2
CaCu
2
O
8
(Bi-2212) phase increased, resulting in an almost 50:50 ratio of Bi-2223:Bi-2212. Energy-dispersive X-ray analysis indicated the presence of Zn and Po in some irradiated samples due to neutron activation. The onset transition temperature (
T
c-onset
) and zero transition temperature (
T
c-zero
) for the non-irradiated sample was 118 K and 105 K, respectively. The irradiated samples showed lower
T
c-onset
(112 to 115 K) and
T
c-zero
(100 to 104 K). AC susceptibility showed a transition temperature (
T
c
χ
′
) around 108 to 109 K. The imaginary part of the susceptibility showed intergranular loss peak temperature (
T
p
) from 89 to 96 K. Intermediate fluence of fast neutron irradiation did not affect the intergrain coupling and pinning strength of (Bi
1.6
Pb
0.4
)Sr
2
Ca
2
Cu
3
O
10
. However, higher fluence severely damaged the microstructure and degraded the flux pinning strength of (Bi
1.6
Pb
0.4
)Sr
2
Ca
2
Cu
3
O
10
.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Composites containing cobalt oxide (Co.sub.3O.sub.4) nanocubes integrated with multiwall carbon nanotubes (MWCNT) were synthesized by a hydrothermal route. The fractions of MWCNTs in the composite ...were varied from 4, 8, 12, 16 and 20 wt.%, and the resulting materials are denoted as C1, C2, C3, C4 and C5, respectively. The formation of products with high structural crystallinity was confirmed by X-ray photoelectron spectroscopy, Raman spectroscopy and X-ray diffraction. A morphological study by field emission scanning electron microscopy and high resolution transmission electron microscopy showed the successful integration of Co.sub.3O.sub.4 nanocubes to the MWCNTs with an average particle size of ~32 nm. The surface of a glassy carbon electrode (GCE) was modified with the nanocomposites in order to evaluate the electrochemical performance of the nanocomposites. Cyclic voltammetry showed that the C4-modified GCE displays best performance in terms of oxidation potential and peak current in comparison to that of a bare GCE, Co.sub.3O.sub.4 nanocubes, or GCEs modified with C1, C2, C3 or C5. The detection limit (at an S/N ratio of 3) is 0.176 nM by using chronoamperometry, and the linear range is between 1 and 20 muM.
HCl-doped polyaniline (PANI) and polymeric composites of polyaniline–cobalt chloride (PANI–CoCl
2
) were synthesized in the laboratory via an in situ oxidative polymerization technique. Their ...chemical, structural and morphological properties were examined through FESEM, XRD, EDX and FTIR spectroscopic techniques. The electrochemical performance of the as-prepared composites was examined through cyclic voltammogram, electrochemical impedance spectroscopy and galvanostatic charge/discharge measurement techniques. The thermal properties of the as-prepared composites were examined through thermal gravimetric analysis technique. The results obtained were found satisfactory and well suitable for its use as hybrid electrode materials for supercapacitor application.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Gel polymer electrolytes (GPEs) are more preferable than liquid electrolyte for dye-sensitized solar cells (DSSCs) due to several advantages. However, GPEs have poor ionic conductivity which renders ...the low efficiency of DSSCs. GPE systems based on poly(ethylene oxide) (PEO) as host polymer, sodium iodide (NaI) salt, and various amount of zinc oxide (ZnO) (1, 3, 5, and 7 wt%) were prepared and optimized. The highest ionic conductivity obtained for these systems was 7.05 × 10
−3
S cm
−1
for the GPE at 5 wt% of ZnO. The formation of structural features and complexes of the materials have been confirmed by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). Under the illumination of AM 1.5 (100 mW cm
−2
), the fabricated DSSCs (with an arrangement of FTO glass/TiO
2
/N719dye/electrolyte/Pt/FTO glass) achieved the maximum power conversion efficiency of 6.94%, with a maximum short-circuit current density (
J
SC
) of 18.75 mA cm
−2
, open-circuit voltage (
V
OC
) of 0.666 mV, and fill factor (FF) of 55.6%.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Gel polymer electrolytes (GPEs) are prepared by mixing poly (propylene) carbonate (PPC) with various weight percentages of 1-butyl-3-methylimidazolium iodide (BmimI) ionic liquid. The GPEs consist of ...PPC host polymer, NaI iodide salt, ethylene carbonate (EC), propylene carbonate (PC), BmimI ionic liquid, and iodine (I
2
). The optimum BmimI ionic liquid content was found to be 60 wt% with respect to the wt% of PPC polymer with the highest ionic conductivity of 4.79 × 10
−3
S cm
−1
. Temperature-dependent ionic conductivity studies exhibited that gel polymer electrolytes obey Arrhenius thermal-activated model. X-ray diffraction (XRD) study confirms the complexation between host polymer (PPC polymer), sodium iodide salt, and BmimI ionic liquid. Dye-sensitized solar cells are fabricated and GPEs are sandwiched between the working and counter electrodes and tested under the one Sun illumination. The highest energy conversion efficiency of 6.14% is achieved with the addition of 60 wt% of BmimI.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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