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The recent increase in the use of graphene and its derivatives is due to their exceptional physicochemical, electrical, mechanical, and thermal properties as the industrial materials developed by involving graphene structures can fulfill future needs. In that view, the potential use of these graphene-containing nanomaterials in electronics applications has encouraged in-depth exploration of the electronic, conducting, and other functional properties. The protecting undifferentiated form of graphene has similarly been proposed for various applications, for example, as supercapacitors, photovoltaic and transparent conductors, touch screen points, optical limiters, optical frequency converters, and terahertz devices. The hybrid composite nanomaterials that undergo stimulus-induced optical and electrical changes are important for many new technologies based on switchable devices. As a two-dimensional smart electronic material, graphene has received widespread attention, and with that view, we aim to cover the various types of graphene oxide (GO)-based composites, linking their optical and electrical properties with their structural and morphological ones. We believe that the topics covered in this review can shed light on the development of high-yield GO-containing electronic materials, which can be fabricated as the field moves forward and makes more significant advances in smart optoelectronic devices.

The current effort aims at the morphological displays of TiO2 materials grown on Ti foil substrates using aerosol assisted chemical vapour deposition. Optimization of temperature, surfactant concentrations and substrate orientation has been found to play a vital role in the smart designing of micro/nanostructures, ranging from microspheres, nanopetals, nanospikes to the nanorods. Interestingly, when tested as LIB anode these various morphologies showed a much distinct performance and stability during charge/discharge cycles. The nanorod structures with smooth carbon covering have shown excellent reversibility followed by the nano-petals that showed an impressively stable capacity.

The hydrothermal method has been used to prepare Ni(OH)2 photocathode. The photoelectrochemical (PEC) reduction of CO2 over Ni(OH)2 has been conducted in 0.2 M LiClO4 in aqueous and N,N-dimethylformamide (DMF) medium under visible light irradiation. The thin film was characterized by XRD, UV–Vis, FTIR, FESEM-EDX, BET analysis, and electrochemical method for the determination of phases, bandgap energy, chemical bonding, surface morphology, elemental compositions, surface area, and electrochemical properties, respectively. Based on UV–Vis spectroscopy, the bandgap energy of Ni(OH)2 was 1.8 eV which enabled efficient visible light absorption for the photoreaction. The photocurrent density in aqueous and DMF solution at 0.2 V (vs. Ag/AgCl) was 24 mA cm−2 and 5 mA cm−2, respectively. Acetaldehyde and methanol are the products in aqueous solution, while formic acid and methanol are the products in DMF, after 6 h of photoelectrolysis. The product formations from the photoelectrochemical reduction of dissolved CO2 were 612 and 854 ppm in aqueous and DMF, respectively, where the Faradaic efficiency in aqueous and DMF is 24 and 33%, respectively. Furthermore, throughout the PEC study, the transformation of Ni(OH)2 to NiO plays a significant role in the formation of organic oxygenates from the reduction reaction of CO2.

Herein we report on various surface morphological characteristics of the synthesized cobalt oxide (Co3O4) nanostructures obtained by means of facile one-step hydrothermal method for oxygen reduction reaction (ORR). The synthesized nanostructures of Co3O4 were adequately characterized by field emission scanning electron microscopy (FESEM) fitted with Energy-dispersive X-ray spectroscopy (EDX) elemental mapping, X-ray diffraction (XRD) and Raman techniques. The electrochemical studies were carried out to analyse the performance of as-synthesized catalysts for ORR by cyclic voltammetry (CV), and chronoamperometric (CA) techniques. A higher electrocatalytic response was observed for Co3O4 nanocubes compared with all the other controlled electrodes by CV with a current density of 0.69 mA/cm2 at a potential value of −0.46 V. The as-synthesized material showed adequate tolerance against methanol observed by CV in the presence of 0.5 M methanol, and good stability when compared with commercial Pt/C catalyst using the CA technique.

Silver/titania (Ag/TiO2) nanocomposites, synthesized through a simple one-step chemical reduction method, are used for electrochemical sensing of hydrogen peroxide (H2O2). The images of transmission electron microscopic (TEM) demonstrate a well dispersion of Ag nanoparticles (NPs) with a particle size range of approximately 3 nm on the TiO2 surface, which makes the sensor based on Ag/TiO2 exhibit an excellent performance toward H2O2. The AgNPs presented in the nanocomposite exhibit electrocatalytic reduction of H2O2 and the limit of detection (LOD) is found to be 1.23 µM. Density functional theory (DFT) calculation studies reveal that H2O2 could be easily adsorbed onto Ag rather than TiO2 surface of Ag/TiO2 via a partial electron transfer from Ag to H2O2. The nanocomposite-modified electrode has also excellent selectivity toward the detection of H2O2 over the interferents even when the interferents have a 100 times higher concentration than H2O2.

We demonstrate the preparation of nanostructures cobalt oxide/reduced graphene oxide (Co3O4/rGO) nanocomposites by a simple one-step cost-effective hydrothermal technique for possible electrode materials in supercapacitor application. The X-ray diffraction patterns were employed to confirm the nanocomposite crystal system of Co3O4/rGO by demonstrating the existence of normal cubic spinel structure of Co3O4 in the matrix of Co3O4/rGO nanocomposite. FTIR and FT-Raman studies manifested the structural behaviour and quality of prepared Co3O4/rGO nanocomposite. The optical properties of the nanocomposite Co3O4/rGO have been investigated by UV absorption spectra. The SEM/TEM images showed that the Co3O4 nanoparticles in the Co3O4/rGO nanocomposites were covered over the surface of the rGO sheets. The electrical properties were analyzed in terms of real and imaginary permittivity, dielectric loss and AC conductivity. The electrocatalytic activities of synthesized Co3O4/rGO nanocomposites were determined by cyclic voltammetry and charge-discharge cycle to evaluate the supercapacitive performance. The specific capacitance of 754 Fg-1 was recorded for Co3O4/rGO nanocomposite based electrode in three electrode cell system. The electrode material exhibited an acceptable capability and excellent long-term cyclic stability by maintaining 96% after 1000 continuous cycles. These results showed that the prepared sample could be an ideal candidate for high-energy application as electrode materials. The synthesized Co3O4/rGO nanocomposite is a versatile material and can be used in various application such as fuel cells, electrochemical sensors, gas sensors, solar cells, and photocatalysis.

Titanium oxide (TiO2) is one of the most scrutinized material because of its in-built fundamental properties and has been developed as an outstanding photo-catalytic material intended for many different industrial applications. In order to further explore the properties of TiO2, we prepared Copper-loaded TiO2 (Cu-TiO2) nanoparticles (NPs) for inhibiting the growth of bacterial cells and also to serve as a chemical sensor. The physico-chemical characteristics of the synthesized Cu-TiO2 NPs were characterized by many different techniques for the crystallinity, bonding and functionality, morphology, elemental composition, and absorption characteristics. From the results, we confirm for the formation of anatase phase of TiO2 having a tetragonal crystal system, while the morphology studies indicated that the Cu dope TiO2 has spherical morphology. The elemental analysis confirmed for the inclusion of Cu into TiO2 crystal lattice and the absorption spectroscopic analysis helped for the bandgap calculation and visible light absorption property of Cu-TiO2 NPs. The metal nanoclusters of Cu are observed to be deposited on different phases and sites of TiO2 resulting in the inter-band transitions. Further, the sensitivity of Cu-TiO2 as a chemical sensor is determined by fabricating the electrode at the FTO glass substrate where the ethanol sensitivity was found to be little increased/enhanced with Cu loading. Finally, the antibacterial activity of Cu-TiO2 NPs was confirmed by its activity against various bacterial cultures and are found to be efficient.

Cobalt oxide nanocubes incorporated with reduced graphene oxide (rGO-Co3O4) was prepared by using simple one-step hydrothermal route. Crystallinity and structural characteristics of the nanocomposite were analyzed and confirmed using X-ray diffraction (XRD) and Raman analysis, respectively. The cubical shape of the Co3O4 nanostructures and the distribution of Co3O4 nanocubes on the surface of rGO sheets were identified through field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) mapping analysis, respectively. Raman spectra depicted the presence of D and G bands for GO and rGO with different ID/IG values and thus confirmed the reduction of GO into rGO. The electrochemical study reflects that the rGO-Co3O4 nanocomposite shows good electrocatalytic activity in oxidation of depression biomarker serotonin (5-HT) in phosphate buffer (pH 7.2). The detection of 5-HT was carried out by using rGO-Co3O4 nanocomposite modified glassy carbon electrode under dynamic condition using amperometry technique with a linear range of 1–10 μM. The limit of detection and limit of quantification were calculated and found to be 1.128 and 3.760 μM, respectively with a sensitivity value of 0.133 μΑ·μM−1. The sensor showed selectivity in the presence of different interferent species such as ascorbic acid, dopamine and uric acid.

The current study demonstrates the simplistic approach for the synthesis of SrTiO3 nanocubes incorporated polyaniline flakes (PANI-SrTiO3) by facile in-situ oxidative polymerisation route. The synthesised nanocomposites were characterised by various spectroscopic and surface analysis techniques viz. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and Brunauer-Emmett-Teller analysis (BET). The electrochemical performance of the prepared nanocomposites for energy storage application was evaluated by electrochemical impedance spectroscopy (EIS), galvanostatic charge-discharge (GCD) and cyclic voltammetry (CV) in 1 M of KOH as an electrolyte. The electrochemical investigations demonstrate that the performance of the PANI-SrTiO3 nanocomposite in terms of rate capability was significantly higher as compared to the polyaniline flakes and SrTiO3 nanocubes. Supercapattery was fabricated by combining activated carbon and PANI-SrTiO3-250 as negative and positive electrodes respectively in order to evaluate complete device performance. It is found that fabricated supercapattery gave an energy density of 13.2 W h/kg at a power density of 299 W/kg. Additionally, the fabricated supercapattery also offered excellent stability cycle with 114% capacity retention after 4000 cycles. Moreover, the performance of PANI-SrTiO3-250 was found to be better than the other compositions.

Ilmenite-structured Ni3Mn3Ti6O18 solid solution thin films have been deposited on FTO glass substrates by aerosol-assisted chemical vapor deposition (AACVD) using a 1 : 1 : 2 homogenous mixture of nickel(II) acetate monohydrate (Ni(CH3COO)2·H2O), anhydrous manganese(II) acetate (Mn(CH3COO)2) and titanium(IV) butoxide (Ti(O(CH2)3CH3)4) in the presence of trifluoroacetic acid (TFA) using tetrahydrofuran (THF) as a solvent. Thin films prepared at 575, 600 and 625 °C were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), FT-Raman and X-ray photoelectron spectroscopy (XPS), which demonstrated the development of single phase hexagonal microspherical objects of Ni3Mn3Ti6O18 clusters with precise stoichiometry. A direct optical band gap energy of 2.42, 2.06, and 1.70 eV for thin films fabricated at 575, 600, and 625 °C, respectively, was estimated by UV-vis spectrophotometry. The Ni3Mn3Ti6O18 photoanode deposited at 625 °C for 45 minutes yielded a photocurrent density of 2.05 mA cm−2 at +0.7 V vs. Ag/AgCl/3 M KCl using a 0.5 M NaOH electrolyte under AM 1.5 G illumination (100 mW cm−2) as compared to the films grown at 575 and 600 °C and studied under similar conditions. The charge transfer dynamics of the thin films were also explored using the electrochemical impedance spectroscopy (EIS) technique. The Mullikan charge population calculated through density functional theory (DFT) studies carried out at the B3LYP 6-31G(d,p) level for the [Ti2O6]4− unit of ilmenite determined the highest negative charge on the O atom. The frontier molecular orbital energies (EHOMO and ELUMO) and natural bond orbital (NBO) analysis gave a band gap value of 2.03 eV, complementing the experimental results. Band structure analysis of the [Ti2O6]4− slab showed that the valence band and conduction band are comprised of O 2s, O 2p and Ti 3d orbitals. The results of the present investigation point towards the possibility of an ilmenite form of transition metal oxides as a potential broad spectrum visible light absorbing photocatalyst for solar driven water splitting.

Reduced graphene oxide-cobalt oxide nanocube@gold (rGO-Co 3 O 4 @Au) nanocomposite was prepared using a one-pot hydrothermal synthesis. The nanocomposite was characterized using the UV-Vis absorption spectroscopy, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) mapping, X-ray diffraction (XRD) and Raman analyses. The EDX mapping analysis showed the uniform distribution of Au nanoparticles on the Co 3 O 4 surface that made the surface more roughness. The higher degree of reduction of GO was confirmed from the increased intensity ratio of the D and G bands (I D /I G ) of the Raman spectrum during the hydrothermal synthesis. The rGO-Co 3 O 4 @Au nanocomposite exhibited good electrocatalytic activity towards the oxidation of hydrazine in phosphate buffer (pH 7.2). The detection of hydrazine was carried out using amperometry technique and the current response was linear in the range of 10–620 μM. The limit of detection was found to be 0.443 μM. The selectivity of the nanocomposite for the sensing of hydrazine was studied with the interferents such as NO 3 − , SO 4 2− , Cl − , Ag + , Na + , K + , ethanol, 4-nitrophenol, ascorbic acid and glucose. The sensing of different concentration of hydrazine present in the real water samples was analysed and an appreciable recovery was found.

Nitrogen-doped reduced graphene oxide (NrGO) sheets decorated with Co(OH)2 nanoflakes were prepared by a single-step hydrothermal process. The morphological and structural characterizations of as synthesized NrGO@Co(OH)2 nanoflakes were performed by field emission scanning electron microscopy (FESEM), EDX-mapping and X-ray diffraction (XRD). NrGO@Co(OH)2 nanoflakes modified glassy carbon electrode (GCE) was used for electrochemical sensing of dopamine in neutral medium. The nanocomposite modified electrode showed enhanced electrochemical sensing ability for the detection of dopamine and the limit of detection (LoD) was found to be 0.201 μM with a sensitivity value of 0.0286 ± 0.002 mA mMâ1. Interference studies revealed that NrGO@Co(OH)2âGCE endow excellent selectivity for DA detection even in the presence of higher concentration of common co-existing physiological interfering analytes. Additionally, proposed sensor demonstrated excellent performance in urine samples with promising reproducibility and stability. Keywords: Nitrogen doped graphene, Dopamine, Electrochemical sensor, Amperometric detection

The authors show that the electrocatalytic performance toward the detection of nitric oxide (NO) can be enhanced by making use of gold nanoparticles (AuNP) in a matrix consisting of reduced graphene oxide and Nafion (rGO-Nf). The rGO-Nf@Au nanohybrid was synthesized via a hydrothermal method. The spherical AuNP have diameters in the range from 50 to 200 nm as proven by field emission scanning electron microscopy (FESEM). A glassy carbon electrode (GCE) modified with the nanohybrid displays excellent electrocatalytic activity towards NO oxidation compared to other kinds of modified electrodes. Best operated at a voltage of +0.8 V (vs. SCE), the amperometric response was linear in the 1 μM to 0.16 mM nitrite concentration range, with 0.5 μM detection limit (at an S/N ratio of 3). The high surface area of the AuNP along with the synergistic effect of AuNP and rGO-Nf film on the signal current is believed to cause the enhanced electrocatalytic activity of the nanohybrid. The sensor is not interfered by dopamine (DA), ascorbic acid (AA), uric acid (UA), glucose, urea, and NaCl even in 5-fold higher concentrations. In our perception, the rGO-Nf@Au modified electrode is a promising tool for highly sensitive and selective amperometric sensing of NO.

Composites containing cobalt oxide (Co3O4) 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 Co3O4 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, Co3O4 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 μM.

Cobalt oxide (Co 3 O 4 ) nanocubes were incorporated into reduced graphene oxide (RGO) using a simple single-step hydrothermal reaction for an electrocatalytic oxygen reduction reaction (ORR). The obtained nanohybrid structure of RGO@Co 3 O 4 was adequately characterized using field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Raman spectroscopy, UV-visible spectroscopy, and Fourier transform infrared (FT-IR) spectroscopy. The RGO@Co 3 O 4 nanohybrid with 4 wt% of graphene oxide modified glassy carbon (GC) electrode exhibited better electrocatalytic activity in terms of the current density, overpotential and stability, compared to the other controlled modified electrodes and commercial Pt/C catalyst for the ORR in an alkaline medium. The RGO@Co 3 O 4 nanohybrid showed good methanol tolerance for the ORR in the presence of 0.5 M methanol.

A sensitive and selective detection of dopamine (DA) by a sensor based on cobalt oxide (Co 3 O 4 ) nanograin-decorated reduced graphene oxide (rGO) composite modified glassy carbon electrode (GCE) is reported. The rGO-Co 3 O 4 nanograin composites are synthesized by a facile hydrothermal route and optimized by varying the contents of rGO (5.7, 7.4, 9.1 and 10.7 wt%, denoted as C1, C2, C3 and C4 respectively). The crystallinity of the composite is examined by X-ray diffraction (XRD). Raman spectrum revealed the successful reduction of graphene oxide (GO) into rGO. The surface morphology through field emission scanning electron microscopy (FESEM) revealed that the granular-shaped Co 3 O 4 are decorated on rGO matrix with an average particle size of ∼35 nm. For electrochemical oxidation of DA, glassy carbon electrode (GCE) is modified with nanocomposites. Cyclic voltammetric results show that C3 modified GCE exhibit enhanced electrocatalytic performance in terms of oxidation potential and peak current in comparison to those of bare GCE, Co 3 O 4 nanograins, C1, C2 and C4 modified GCE. The choronoamperometric studies indicate that C3 modified GCE exhibit a low detection limit of (S/N = 3) 0.277 μM in the linear range of 1–30 μM. In addition, C3 demonstrates good selectivity towards the detection of DA in the presence of a 100-fold higher concentration of ascorbic acid, glucose and uric acid as the interfering species. The electrochemical sensing studies suggest that 3D rGO-Co 3 O 4 nanograins endow excellent catalytic activity, high selectivity and sensitivity towards DA.

The present work deals with the improved antimicrobial and photocatalytic efficacy of gold (Au) decorated onto titanium dioxide (TiO2) nanoparticles (NPs). For the synthesis, the TiO2 NPs were first prepared by the hydrothermal method, followed by the introduction of AuNPs via seed growth method to generate Au@TiO2 NPs. The various physical characterization techniques like powder XRD, UV–vis, FTIR, DLS, zeta potential, and HRTEM analysis were applied for the typical understanding of crystal, optical, functional, surface, and morphological properties of Au@TiO2 nanohybrids. Besides, the antimicrobial susceptibility testing of Au@TiO2 nanohybrids against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Candida albicans (C. albicans) bring out the containment efficacy as compared to that of TiO2 and AuNPs. Further studies on the photocatalytic effect of Au@TiO2 nanohybrids towards the degradation of methylene blue (MB) dye attributed significantly enhanced catalytic activity. The enhanced activity of core-shell Au@TiO2 NPs may be due to the improved light-harvesting efficiency based on the resonance of Au ameliorating improved catalytic activity to TiO2. This doping process with the transition metals might enhance the photocatalytic efficacy which finds its implications in the biomedical as well as for the bioremediation processes.

An iron oxide-silicon dioxide coated titanium dioxide (TiO2-Fe2O3@SiO2) incorporated reduced graphene oxide (rGO) nanohybrid was prepared by a simple hydrothermal method using titanium tetraisopropoxide (TTIP) and graphite flakes as the precursors. Tetraethoxysilane (TEOS) was used to form a SiO2 coating on Fe2O3 nanoparticle surface (Fe2O3@SiO2). The presence of SiO2 layer would facilitate the formation of Fe2O3 on the TiO2 surface by an electrostatic attraction that led to the formation of TiO2-Fe2O3@SiO2. The transmission electron microscopy (TEM) results revealed the successful attachment of Fe2O3@SiO2 particles to the TiO2 surface and a uniform distribution of TiO2-Fe2O3@SiO2 composites on the rGO sheet. Furthermore, the rGO/TiO2-Fe2O3@SiO2 nanohybrid modified platinum (Pt) electrode was used for the electrocatalytic oxidation of methanol in alkaline medium. The rGO/TiO2-Fe2O3@SiO2 nanohybrid with weight ratio of 1:3:1 (rGO:TiO2:Fe2O3) showed a higher electrocatalytic activity toward methanol oxidation with an anodic peak current density of 2.45 mA/cm2. Moreover, the nanohybrid displayed a higher stability with 91.58% retention of the initial current density after 5000 s in long term current-time curve. This newly prepared rGO/TiO2-Fe2O3@SiO2 nanohybrid could be a promising anodic catalyst for the direct methanol fuel cells (DMFCs) application.

Folates are essential micronutrients for human health. To determine the total folate content, the extraction and quantification of seven monoglutamate folate derivatives in cereals (maize, rice, and wheat) were optimised and validated in this study. Di-enzyme treatment with α-amylase and rat conjugase was proved ideal for folate extraction from the cereal grains. The quantification method by liquid chromatography-tandem mass spectrometry was validated based on its matrix effect, linearity, sensitivity, recovery, inter-day and intra-day precision. The limits of detection and quantification of folate derivatives ranged from 0.03–0.88 and 0.1–1.0 μg/100 g among the three cereal samples. The absolute recoveries of most folate derivatives were 72–96 % for these cereal samples, with the exception of dihydrofolate, tetrahydrofolate, and folic acid (44–65 %). The inter-day and intra-day precisions were

The present work reports the facile and green synthesis of silver nanoparticles from Catharanthus Roseus (C. Roseus) dried barks extract doped with graphene oxide (AgNPs/GO). The deposition of silver nanoparticles onto graphene oxide sheets were confirmed by UV–vis spectrometer and X-ray diffraction analysis. The synthesized AgNPs/GO displayed high crystallinity with absorption peak at about 400 nm. TEM analysis showed that biosynthesized AgNPs are mostly in a spherical form with particles size ranging from 1 to 26 nm. The existence of functional groups such as hydroxyl, epoxy and carboxylic in GO are believed to be the reason for the anionic character of the synthesised nanocomposite. Whilst, AgNPs functions as spacers assisting the segregation of stacked GO sheets thus promoting larger surface area. The evaluation of its adsorption capacity was carried out against methylene blue (MB) dye. The addition of biosynthesized AgNPs on GO sheets synergistically envisages the best adsorption capacity at 100 mM of AgNPs with almost a complete removal of MB in less than 5 min. Based on the pseudo second-order kinetic approach, the highest adsorption rate constant of 1.4563 g mg−1 min-1 was obtained. The overall adsorption capacity was enhanced due to the presence porous nanocomposite with highly disperse AgNPs anchored onto the surface of GO sheets.

In this work, we emphasize the green synthesis of cuprous oxide (Cu2O) nanoparticles (NPs) by Fehling's route using banana (Musa acuminate) fruits where the formation of products by the involvement of natural ingredients is considered to be the solvent-free route. The as-synthesized Cu2O samples were thoroughly characterized by various analytical techniques in order to fully understand the surface bonding and functional groups, optical properties, surface charges, phase purity and crystallinity, surface morphological features, and elemental analysis. On testing of the photocatalytic activity, the material is investigated to be p-type Cu2O and exhibited highly efficient photocatalytic behavior due to the interfacial structure that tends to reduce the recombination rate of a photogenerated electron (e−) - hole (h+) pairs. Further, we have explored this property for the degradation of organic contaminants, methylene blue and found that the material is very effective towards the photochemical degradation of pollutants.

The article describes a glassy carbon electrode (GCE) modified with a nanocomposite consisting of graphene oxide and silver nanoparticles, and its application to amperometric determination of hydrogen peroxide (H2O2). Cyclic voltammetry with this modified electrode reveals efficient electrocatalytic reduction of H2O2. The response to H2O2 at a working potential of −0.3 V (vs. Ag/AgCl) is linear in the 100 μM to 11 mM concentration range at pH 7.2. The limit of detection is 28.3 μM (at an S/N ratio of 3). Good selectivity is observed over physiological interferents such as dopamine, ascorbic acid, uric acid and glucose.

This work demonstrates the high performance graphene oxide (GO)/PEDOT:PSS doubled decked hole transport layer (HTL) in the PCDTBT:PC71BM based bulk heterojunction organic photovoltaic device. The devices were tested on merits of their power conversion efficiency (PCE), reproducibility, stability and further compared with the devices with individual GO or PEDOT:PSS HTLs. Solar cells employing GO/PEDOT:PSS HTL yielded a PCE of 4.28% as compared to either of individual GO or PEDOT:PSS HTLs where they demonstrated PCEs of 2.77 and 3.57%, respectively. In case of single GO HTL, an inhomogeneous coating of ITO caused the poor performance whereas PEDOT:PSS is known to be hygroscopic and acidic which upon direct contact with ITO reduced the device performance. The improvement in the photovoltaic performance is mainly ascribed to the increased charge carriers mobility, short circuit current, open circuit voltage, fill factor, and decreased series resistance. The well matched work function of GO and PEDOT:PSS is likely to facilitate the charge transportation and an overall reduction in the series resistance. Moreover, GO could effectively block the electrons due to its large band-gap of ~3.6 eV, leading to an increased shunt resistance. In addition, we also observed the improvement in the reproducibility and stability.