Nicotinamide Adenine Dinucleotide (NADH) is an important coenzyme in the human body that participates in many metabolic reactions. The impact of abnormal concentrations of NADH significantly causes ...different diseases in human body. Electrochemical detection of NADH using bare electrode is a challenging task especially in the presence of main electroactive interferences such as ascorbic acid (AA), uric acid (UA) and dopamine (DA). Modified electrodes have been widely explored to overcome the problems of poor sensitivity and selectivity occurred from bare electrodes. This review gives an overview on the progress of using conducting polymers, polyelectrolyte and its composites (co-polymer, carbonaceous, metal, metal oxide and clay) based modified electrodes for the sensing of NADH. In addition, developments on the fabrication of numerous conducting polymer composites based modified electrodes are clearly described.
•We review the conducting polymer and its composite materials for NADH sensing.•The detection mechanisms and the advantages of materials are emphasized.•Future perspectives and possible challenges in this area are outlined.
In the present work, synthesis of bimetallic copper zinc tungstate (CuZnWO
4
) nanoparticles with reduced graphene oxide (CuZnWO
4
/rGO) via one-step hydrothermal technique was attempted. The ...synthesized CuZnWO
4
/rGO composite are characterized by Fourier transform infrared spectroscopy (FTIR), Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–Vis diffuse reflectance spectroscopy (UV DRS) and Photoluminescence (PL). The photocatalytic performance is examined by the degradation of methylene blue (MB) dye under visible light irradiation. The MB dye is almost 73% degraded within 80 min. Further, the electrochemical performance of hybrid CuZnWO
4
/rGO composite showed the specific capacity (SC) of 480 F/g at 4 A/g in 6 M KOH electrolyte with excellent cyclability conserving a capacitance retention of 127% after 5000 cycles due to increase diffusion of electrolyte ions to the electrode materials. These results support the hybrid CuZnWO
4
/rGO composite as an appropriate electrode material for high-performance SCs electrode and an auspicious catalyst for the degradation of dye (organic) contaminants in aqueous media.
This article presents the effect of different calcination temperatures on the structural, morphological and capacitance of nickel phosphate (Ni
3
(PO
4
)
2
) as an electrode material for ...supercapacitor applications. Ni
3
(PO
4
)
2
was synthesized
via
a sonochemical method followed by calcination at different temperatures (300, 600 and 900 °C, denoted as N300, N600 and N900, respectively). The phase structure and purity of Ni
3
(PO
4
)
2
were confirmed by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The surface morphologies showed that the particle size increased with increasing the calcination temperatures. The electrochemical performance of N300, N600 and N900 were investigated using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) in a 1 M KOH electrolyte. It was found that N300 exhibited the maximum specific capacity of 620 C g
−1
at 0.4 A g
−1
, which was significantly higher than N600 (46 C g
−1
) and N900 (14 C g
−1
). Here, the enhanced electrochemical performance was obtained due to the amorphous structure and augmentation of the redox active sites of the N300 particles. Additionally, the fabricated N300//activated carbon based asymmetric supercapacitor can be cycled reversibly at a cell voltage of 1.45 V. The device exhibited an energy density of 76 W h kg
−1
and a power density of 599 W kg
−1
with life cycles of 88.5% capacitance retention after 3000 cycles.
This article presents the effect of different calcination temperatures on the structural, morphological and capacitance of nickel phosphate (Ni
3
(PO
4
)
2
) as an electrode material for supercapacitor applications.
We investigated different molar concentrations of cobalt precursor intercalated reduced graphene oxide (rGO) as possible electrode materials for supercapacitors. Cobalt oxide (Co 3 O 4 ) nanocubes ...intercalated reduced graphene oxides (rGO) were synthesized via a facile hydrothermal method. It has been found that the Co 3 O 4 particles with a cubical shape are decorated on rGO matrix with an average size of ∼45 nm. The structural crystallinity of rGO–Co 3 O 4 composites was examined by X-ray diffraction (XRD). Raman spectroscopy confirmed the successful reduction of GO to rGO and effective interaction between Co 3 O 4 and the rGO matrix. The electrochemical performances of rGO–Co 3 O 4 electrodes were examined using cyclic voltammetry and charge–discharge techniques. The maximum specific capacitance (278 F g −1 ) is observed at current density of 200 mA g −1 in the C2 electrode resulting from effective ion transfer and less particle aggregation of Co 3 O 4 on the rGO matrix than in the other electrodes. C2 exhibits good rate capability and excellent long-term cyclic stability of 91.6% for 2000 cycles. The enhanced electrochemical performance may result from uniform intercalation of cobalt oxide over the rGO. These results suggest that the Co 3 O 4 intercalated rGO matrix could play a role in improved energy storage capability.
Exploiting novel, low cost, and efficient photocatalysts for removal of pollutant waste water was significant to resolve the energy crisis and environment remediation. Here, we report the synthesis ...of nickel sulphide (NiS)/reduced graphene oxide (rGO)-based heterojunction photocatalyst using one step hydrothermal method. The intimate contact between NiS and rGO was suggested to quicken the transfer of photogenerated electrons from NiS to rGO, reducing the recombination of charge transporters and hence increasing the photocatalytic activities. The physico-chemical properties of the NiS/rGO heterojunction photocatalysts were scientifically studied with different characterization methods. The most efficient photocatalytic performances under solar light irradiation have been carefully assessed, and the NiS/rGO heterojunction nanocomposites exhibit photocatalytic degradation on methylene blue (MB). The removal percentage for MB can reach maximum at ~ 87% in ~ 100 min under solar light treatment. Moreover, the NiS/rGO heterojunction nanocomposite revealed highly stable for removing MB even after four successive experiments. Therefore, the experimental results demonstrated that the prepared NiS/rGO nanocomposites showed significant photocatalytic performance, thus supporting probable active heterojunction nanocomposite for energy conversion as well as in environmental remediation.
In this present investigation, we have fabricated Polyvinylpyrrolidone nanocomposites (PVP/Y
2
O
3
NCs) by hydrothermal method. Pristine Y
2
O
3
nanoparticles are effectively intercalated with the ...PVP matrix according to the decrease in bandgap energy from 3.62 to 3.36 eV. The FE-SEM and HR-TEM studies confirmed that the spherical structured PVP/Y
2
O
3
nanoparticles with an average size of 30 nm. TGA curves of different PVP/Y
2
O
3
NCs showed that favourable thermal sustainability even after 640 °C without any weight loss. The antibacterial activity of PVP/Y
2
O
3
NCs was studied against various Gram-positive and Gram-negative pathogenic bacteria. The zone of inhibition (ZOI) of Gram-negative bacteria is significantly higher than that of Gram-positive bacteria at 1.5% PVP concentration of PVP/Y
2
O
3
NCs. The results reveal that PVP/Y
2
O
3
NCs more cytotoxic with the IC50 value of 43.34 μg/mL. Moreover, PVP/Y
2
O
3
NCs displayed the enhanced biocompatibility, high stability and anticancer activity.
In this paper, we are reporting the fabrication of memristor device (Ag/TiO2/Cu) using electrohydrodynamic inkjet printing technology. The titanium oxide (TiO2) active layer was deposited using ...electrohydrodynamic atomization technique. The metal electrodes were patterned by using electrohydrodynamic printing technique. The crystalline nature, surface morphology and optical properties of as deposited TiO2 films were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-visible spectroscopic analysis respectively. XRD and SEM studies revealed that the presence of anatase TiO2 with uniform deposition. The optical transmittance of the deposited TiO2 films was observed to be 87% in the visible region. The fabricated memristor device (Ag/TiO2/Cu) exhibits bipolar resistive switching behavior within the low operating voltage (± 0.7V). Our results ensure that the printed technology provides breakthrough solution in the electronic memory device fabrication.
► Electrohydrodynamic inkjet technique was used to fabricate memristor device. ► The active layer TiO2 presence in the form of anatase. ► The optical transmittance of the TiO2 films was 87% in the visible region. ► Uniform deposition of TiO2 thin film was achieved. ► The Ag/TiO2/Cu device exhibited a bipolar resistive switching behavior.
A semi-flexible binder-free graphitic carbon nitride (g-C3N4) intercalated polypyrrole (PPy) nanocomposite thin film was prepared via hybrid electrospray technique. A homogeneous thin film was ...achieved by the controlled spray process. A deposited thin film illustrated the amorphous nature of composite with high surface purity and good chemical composition. The surface analysis confirmed the smoother surface with well-defined distinct phases of g-C3N4 and PPy matrix in the composite thin film. The electrochemical studies exhibited that a maximum areal capacity of the thin film was achieved to be 289.6 mF/cm2 at a current density of 0.4 mA/cm2, which is higher than that of pristine PPy (194.8 mF/cm2). The heterostructure electrode illustrated that the life cycles of 99% could be up to 10,000 cycles with low resistance due to the synergetic effect of g-C3N4 and PPy matrix with strong material adhesion (hybrid spray process) on the surface. A binder-free heterostructure thin film will play a significant role in the energy storage application.
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•Fabrication of binder free heterostructure thin film via hybrid spray process.•A composite film exhibits a specific capacity of 289.6 mF/cm2.•The composite electrode has a maximum stability of 99% upto 10,000 cycles.
A facile and fast approach for the synthesis of a nanostructured nickel hydroxide (Ni(OH)2) via sonochemical technique is reported in the present study. The X-ray diffraction results confirmed that ...the synthesized Ni(OH)2 was oriented in β-phase of hexagonal brucite structure. The nanostructured Ni(OH)2 electrode exhibited the maximum specific capacitance of 1256F/g at a current density of 200mA/g in 1M KOH(aq). Ni(OH)2 electrodes exhibited the pseudocapacitive behavior due to the presence of redox reaction. It also exhibited long-term cyclic stability of 85% after 2000 cycles, suggesting that the nanostructured Ni(OH)2 electrode will play a promising role for high performance supercapacitor application.
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•Nanostructured nickel hydroxide was synthesized via one step process.•The non-aggregated β-phase of hexagonal brucite structure was observed.•It exhibited maximum specific capacitance of 1256F/g at 200mA/g.•It exhibited long-term cyclic stability of 93% after 1000 cycles.
Nickel oxide (NiO) was synthesized via a one-step facile method. X-ray diffraction analysis confirmed the face-centered cubic structure of NiO. The bonding nature and surface purity were confirmed ...via Fourier-transform infrared spectroscopy. NiO revealed partial spherical morphology with less particle aggregation. The optical bandgap of NiO was found to be 3.75 eV. Cyclic voltammetry revealed well-defined oxidation and reduction peaks for NiO. The charge–discharge curve exhibited specific capacitance of 184.6 F/g at current density of 0.3 A/g. NiO electrode exhibited longer cyclic stability of 93 % up to 1500 cycles. In addition, NiO + H
2
O
2
revealed efficient photocatalytic degradation of methylene blue (organic pollutant) under visible-light irradiation with degradation efficiency of ~88 %. These results confirm that nanosized NiO is more suitable for dual application.
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