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Electrochemical water splitting proved to be one of the most attractive sources of green fuel energy but the easy and time-consuming synthesis of highly active, low-priced, steady and earth-abundant metals electrocatalysts is still a challenge among the researcher. In this work, we have reported the fabrication of Group IV transition metal (M = Ti, Hf, and Zr) based phospho-chalcogenides and their composite with MoTe2 via simple hydrothermal synthesis process. The prepared nanocomposites (MP2S6@MoTe2) were compared with respect to their best performance towards HER over the entire pH range. Among the different kind of prepared nanocomposite, TiP2S6@MoTe2 exhibited special almond like shape with self-layered morphology and henceforth selected as best catalyst on the basis of their low Tafel slope, small onset potential, low charge transfer resistance and small overpotential value over the wide range of pH. It was also found that nanocomposites modified working electrode showed long cycle durability in the acidic pH in controlled potential electrolysis study.

Herein, we report the advanced polymer vesicle [made up of triblock polymer: poly(ethylene oxide)

In this chapter, we will learn about the fundamental synthesis of materials and nanomaterials. Materials like metal, metal semiconductors, ceramics, and polymers are synthesized via different methods such as solid-state synthesis, chemical vapor transport, sol-gel synthesis, and melt growth. In contrast, thin-film materials were synthesized by chemical vapor deposition, laser ablation, sputtering, and molecular beam epitaxy technique. The nanomaterials are classified as metal-containing, dendrimers, carbon-containing, and mixture of materials, which are synthesized by physical, chemical, and biological techniques. The synthetic physical procedures are ball milling process, electron beam lithography, inert gas condensation synthesis method, physical vapor deposition methods, and laser hydrolysis methods. The synthetic chemical procedures are hydrothermal process, sol-gel process, polyol process, microemulsion, microwave-assisted synthesis, and bio-assisted methods.

In this work, a sensitive and selective molecularly imprinted polymer modified electrochemical sensor was developed for the detection of the hepatocellular carcinoma (HCC) biomarker, alpha feto protein (AFP) on the surface of specifically designed Ag/AgCl nanoparticles. Herein, for the first time, the effect of the shape of nanoparticles on the behavior of an imprinted polymer was studied using cube- and spherical-shaped Ag/AgCl nanoparticles. It was found that cube-shaped nanoparticles have high surface to volume ratios and higher electrocatalytic activity, and are, therefore, a suitable platform for the synthesis of imprinted polymers. Herein, we have demonstrated how a change in the morphology of the nanomaterials can affect the electrochemical and adsorption properties of an imprinted polymer towards the target analyte (here, AFP). A cube-shaped nanoparticle@imprinted polymer was used for the fabrication of the electrochemical sensor, the analytical performance of which was shown, by a square wave stripping voltammetric technique, to be good for the detection of AFP. The current response of the electrochemical sensor was linear for AFP concentrations in the range from 0.10 to 700.0 pg mL

The synthesis of iridium oxide decorated erbium pyrosilicate (Er2Si2O7:IrO2) was performed by a simple sol–gel technique. By simple alteration of the reaction parameters, different shapes (i.e., cubes, rods, large spheres, small spheres, and sheets) of Er2Si2O7:IrO2 were obtained and their catalytic activities were tested toward the hydrogen evolution reaction (HER). Among the different morphologies of Er2Si2O7:IrO2, cube-shaped nanoparticles (Er2Si2O7:IrO2–5) with sharp edges provided promising HER activity over a wide pH range from 0 to 14 in acidic, neutral, and basic media. Er2Si2O7:IrO2–5 exhibited an onset potential of −0.076 V with a very high current density of 252 mA cm–2 (at −0.54 V). The overpotential and Tafel slope for the HER using Er2Si2O7:IrO2–5 were found to be 130 mV and 49 mV/dec, 170 mV and 59 mV/dec, and 190 mV and 67 mV/dec in 0.5 M H2SO4, 1.0 M KOH, and 2.0 M PBS, respectively. The low cost, highly active electrocatalyst shows robust durability over acidic medium for nearly 250 min....

Now-a-days, transition metals have been earnestly exposed to energy harvesting field due to their advantages such as low cost, high catalytic activity, high stability in both basic as well as acidic media. Co3O4 based electrocatalysts have grabbed the attention of researchers due to their high catalytic activity towards oxygen evolution reaction (OER). In this work, a facile hydrothermal method was adopted as the fabrication technique of synthesizing Co3O4 and the as-prepared metal oxide nanocomposite was further devised by adding the appropriate amount of transition metal dopants to investigate their effect on the catalytic activity following their electrochemical behaviors. The synthesized transition metal doped metal oxides were systematically characterized by different techniques. The electrochemical studies were carried out and Co3O4 was found to exhibit a high OER activity in alkaline medium. With the further addition of dopants such as chromium, iron and nickel, the catalytic activity of Co3O4 was enhanced, and among them, the Cr-Co3O4 shows the best electrocatalytic activity followed by Ni-Co3O4, Fe-Co3O4 and Pure Co3O4.

The nanocomposite of graphene-iron oxide-polyvinyl alcohol (PIG) was synthesized via simple one-pot hydrothermal method and was used in the modification of pencil graphite electrode for developing an electrochemical sensor. Graphene (G) and iron oxide-graphene (IG) composites were synthesized for providing a comparative study. The structural properties of the prepared PIG were studied through X-Ray diffraction (XRD) technique, whereas the morphological analysis was conducted through field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) study. The chemical states of elements present in the prepared composite were confirmed using X-ray photoelectron spectroscopy (XPS) and the functional groups present in the composite were investigated through Fourier transform infrared (FTIR) spectroscopy. The existence of iron oxide nanoparticles along with PVA polymer in PIG composite enhances the electroactive area (0.073 cm2) and roughness factor (0.186) along with the sensitivity of the material. The square wave voltammetry technique was used for detecting the bio-molecule i.e. vitamin C. At optimized condition, the PIG modified electrode shows a high linear range (40 μM–4100 μM), low limit of detection (0.234 μM) and higher sensitivity (1597.03 μA cm−2 mM−1). The PIG material also provides a good stability towards detection of vitamin C.

With decreasing fossil fuels and rising environmental issues, harvesting energy in a large amount and in a clean way has been a great challenge for the whole world. Developing the efficient electrocatalysts with less expense and achieving the better electrocatalytic behavior for oxygen evolution reaction (OER), oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) is very essential for extensive commercialization of fuel cells, water electrolyzers and metal air batteries. In the same pursuit, herein, we report a bifunctional coral-like NiCo2O4 nanostructure supported on reduced graphene oxide (rGO) sheets, which was prepared by a facile, controlled hydrothermal reaction protocol. The structural, morphological and electrochemical characterizations have been carried out to explore the properties of this nanocomposite. The unique morphology, large electroactive surface area and the synergistic effect of the metal ions on the electrocatalytic activity makes this material a suitable candidate for electrochemical water splitting. The low onset potential, high current density, lower Tafel slope and long-term stability in both HER and OER has been shown by rGO-NiCo2O4 coral like nanostructure, which reveals the high catalytic activity of this material, underlying the finding and importance of current work.

In this work, we report on a dual-behavior electrochemical/optical sensor for sensitive determination of Imidacloprid by fluorescent dye (fluorescein, FL) and imprinted polymer modified europium doped superparamagnetic iron oxide nanoparticles (FL@SPIONs@MIP). The imidacloprid (IMD)-imprinted polymer was directly synthesized on the Eu-SPIONs surface via Activators regenerated by the electron transfer-atom transfer radical polymerization (ARGET-ATRP) technique. Preparation, characterization and application of the prepared FL@SPIONs@MIP were systematically investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), fluorescence spectroscopy and electrochemical techniques. The electrochemical experiments exhibited a remarkable selectivity of the prepared sensor towards IMD. Determination of IMD by the square wave stripping voltammetry method represented a wide linear range of 0.059–0.791 μg L−1 with a detection limit of 0.0125 μg L−1. In addition, the fluorescence method shows a linear range of 0.039–0.942 μg L−1 and LOD of 0.0108 μg L−1. The fluorescence property of prepared FL@SPIONs@MIP was used for rapid, on-spot but selective detection of IMD in real samples. The proposed electrode displayed excellent repeatability and long-term stability and was successfully applied for quantitative and trace level determination of IMD in several real samples.

Shape specific nanoparticles are getting a tremendous research interests due to their change in property with the shape. As far our knowledge, the impact of change in the shape of nanoparticle used as platform during synthesis of molecularly imprinted polymers (MIPs) has not been reported or tried. Herein, we have studied the effect of shape of silver nanoparticles (AgNPs) on the performance of MIPs. For this, different shaped (spherical, hexagon and cube) AgNPs were prepared by green-synthesis approach, modified with vinyl group, embedded into the shell of magnetic carbon nanoparticles and used as one of the functional monomer during tramadol imprinted polymer synthesis. The resulting MIP@Ag/C@Fe 3 O 4 was used for adsorption, removal and detection of tramadol, which is gaining importance due to their recent ban in several countries. The change in behaviour of resulting MIPs, with the change in shape of the incorporated nanoparticles was studied in terms of electrocatalytic activity, surface area, adsorption capacity, and removal efficiency. Among their different shaped colleagues cube shaped AgNPs win the MIP race and exhibited the best performance owing to the presence of more facets in comparison to the others. Furthermore, the cube shaped AgNPs based MIP (MIP@Cube-Ag/C@Fe 3 O 4 ) was successfully applied for the detection of tramadol in human sera and pharmaceutical samples without any cross-reactivity. In addition to the advantages of low cost, high selectivity, sensitivity, good adsorption and removal properties, the resulting MIP format is biodegradable too i.e. the material will not create any environmental hazards after their use and could be very easily disposed off from the medium.

The main motif of this work is to fabricate a highly efficient, economic, nanodisc shaped trifunctional electrocatalyst using a tungsten trioxide modified carbon nanosheet decorated with palladium nanoparticles. The beauty of this work is that a special carbon precursor is used for the synthesis of the electrocatalyst, a waste material, i.e., cow dung. The performance of the cow dung derived nanodisc electrocatalyst (Pd@WO3-NDs) toward oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and hydrogen evolution reaction (HER) is compared with three other electrocatalysts (derived from graphene oxide, chitosan, and graphite carbon sources) also, and it is found that Pd@WO3-NDs show superior performance over that of the other three. The electrocatalyst exhibits the lowest onset potential (1.32 V vs NHEs), highest current density (492 mA cm–2), lowest overpotential (113 mV), and lowest Tafel slope (62.8 mV dec–1) for OER; an onset potential of 1.02 V, overpotential of 195.0 mV, and Tafel slope of...

Single phase Fe x Sn 1−x O 2 nanoparticles of size 2–16 nm were synthesized by simple co-precipitation method. The X-ray diffraction (XRD) pattern shows pure tetragonal rutile phase of SnO 2 without any indication of other impurity phases related to Fe doping. A systematic decrease in the crystallinity (increased peak broadening) was observed with increasing doping percentage owing to the increase in distortion and tensile nature of residual compressive strain. The optical band gap energy of the Fe x Sn 1−x O 2 nanoparticles decreases from 3.68 eV to 2.35 eV with increasing Fe content. The observed tunable optical properties with Fe-doping variations can be attributed to the replacement of Sn 4+ ions by Fe 3+/2+ ions in tetragonal rutile phase of SnO 2 with no evidence of metallic Fe. The room temperature photoluminescence spectra of Fe x Sn 1−x O 2 nanoparticles show broad emissions at about 347 and 437 nm under 270 nm excitations. These emissions correspond to the introduction of Fe-impurity, defect concentration and the possibility that both the hole and the electron can trap in the oxygen vacancy sites at the surface of the SnO 2 nanoparticles which act as recombination center generating the non-radiative emissions. Vibrating sample magnetometer (VSM) measurement suggests that the pure SnO 2 possess diamagnetic behavior while doped nanoparticles exhibit ferromagnetic to superparamagnetic transitions. Initially, these nanoparticles showed strong ferromagnetic behavior at room temperature, however at higher doping percentage of Fe, the ferromagnetic behavior was covered up, and antiferromagnetic nature was dominated. The enhanced antiferromagnetic interaction between adjacent Fe-Fe ions covered up the ferromagnetism at higher doping concentrations of Fe. The value of magnetic moment of the sample increases with Fe concentration and attains maximum value of 0.121178 μB. The co-existing magneto-optical properties make the Fe x Sn 1−x O 2 nanoparticles a promising candidate for various magneto-electronic and spintronics related applications, underlying the findings and importance of current investigations.

In this work, we prepared four different shaped silver nanoparticles (AgNPs) (spherical, rod, hexagonal, and flower shaped) by using the green synthesis approach. The synthesized AgNPs were characterized by UV-vis spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, which showed that AgNPs have a very narrow size distribution with visible and confined geometry and shape. The synthesized AgNPs were modified by 2-bromoisobutyryl bromide, developed as a nanoinitiator, and then used for the synthesis of phenformin-imprinted polymers (MIP@AgNPs). A comparative study was performed between different shaped MIP-modified AgNPs; in addition, the effect of AgNPs on electrocatalytic activity, surface area, adsorption capacity, and electrochemical and photoluminescence sensing of phenformin was also explored. Among the different shaped MIP@AgNPs, the anisotropic AgNPs have multiple facets and planes, i.e., the flower-shaped AgNPs showed the best performance and were successfully applied for trace-level detection of phenformin in an aqueous sample. Furthermore, the MIP@AgNPs were also applied for the detection of phenformin in human serum, plasma, and urine samples without any cross-reactivity effect, suggesting a bright prospect for the use of anisotropic nanomaterials in future clinical trials. (C) 2017 Elsevier B.V. All rights reserved.

The present work is devoted toward the development of a highly efficient, low cost, selective and sensitive technique for the detection, removal and recovery of a popular rare earth element, i.e., gadolinium [Gd]. Herein, the magnetic ordered mesoporous carbon (OMMC) is prepared by a green synthesis approach and used as a core for the preparation of imprinted-OMMC using Gd(III) as a template. The prepared material has been used as a coating sorbent for solid phase microextraction (SPME) fiber as well as filled in a small sized micropipette tip to perform the microsolid phase extraction (μ-SPE) based study. The techniques have been explored for different purposes, i.e., preconcentration and trace level detection of Gd(III) has been done by SPME; however, μ-SPE is used for removal as well as recycling of Gd(III) from wastewater samples. The SPME fiber shows a higher preconcentration factor 1400 for Gd(III) with a limit of detection = 2.34 ng L–1, whereas the μ-SPE cartridge shows a higher adsorption capacit...

Herein, we report the advanced polymer vesicle [made up of triblock polymer: poly(ethylene oxide)-co-poly(Cys-AuNP@FA)-co-poly(3-methoxypropylacrylamide] having encapsulated magnetic nanoparticle capable of targeted methotrexate delivery (having folic acid as tagging agent), photothermal therapy [anisotropic gold nanoparticle (AuNPs)] and stimuli-responsive T1-imaging (as MRI contrast agent). The prepared polymersome, called as magnetopolymersome (MPS), after encapsulation of magnetic nanoparticle (Gd-doped) is not only high yield and simple in synthesis but also possess very high biocompatibility, more than 95% drug encapsulation efficiency and effective near-infrared (NIR) responsive photothermal therapy. The MPS is highly stable under normal physiological environments and other extreme end conditions (like presence of serum or Triton-X 100) and have excellent stimuli-responsive (temperature and NIR) T1-contrast effect in vitro conditions (60.57 mM–1 s–1). To explore the role of shape of AuNPs on the ph...

A pioneering nucleus-targeting dual-functional thermosensitive bubble-generating liposome as drug carrier has been developed with conjugated cell penetrating peptide and photothermal agent (CDs) for multi-color cell imaging and combination (chemo- and photothermal) therapy of cancer, using doxorubicin as drug molecule. The liposome was prepared by ‘in-house’ synthesized precursors molecules, to reduce the cost of production in comparison to the earlier reported liposomes. This drug carrier was proposed to target nucleus of the cancer cells, owing to specific and selective cell-penetrating property of TAT, followed by burst but stable drug release due to decomposition of bubble forming agent present inside the liposome core, by being subjected to near-infrared (NIR) irradiation (i.e. photothermal conversion of radiation to heat). The in-vitro temperature and/or NIR-triggered release study indicated that liposome was sensitive towards heat and able to generate the sufficient temperature of 68 °C in the presence of NIR-laser source. The in vivo experiment was also performed to explore the NIR-responsive hyperthermia in the mice body. The as prepared bubble containing liposome-based drug delivery system exhibits superior stability, no drug leakage and enhanced in vitro and in vivo drug delivery with efficient cancer cell killing via combination therapy. The multicolor fluorescence obtained via CDs improves the accuracy of the cell imaging study as well as works as a key component for photothermal treatment of cancer. The results obtained in the study demonstrated that the designed smart drug carrier have great potential in the field of cancer theragnosis i.e. imaging, targeted drug delivery, and treatment.

In this article, for the first time, we have designed a new reaction mechanism i.e. adjourned-reaction to fabricate shape specific transition metal dichalcogenides based electrocatalyst. Herein, the MoSe 2 /MoO 3 and WSe 2 /WO 3 based different shaped nanohybrids were prepared in a new, economic and creative way by adjourning the complete 24 h hydrothermal reaction for 30 min at an interval of 3 h. By optimizing the temperature and adjourning time different shape of MoSe 2 /MoO 3 and WSe 2 /WO 3 were prepared and from them four specific shapes nanohybrids i.e. MoSe 2 /MoO 3−1 (150 °C) Marigold like flower, MoSe 2 /MoO 3-2 (200 °C) thin rod agglomerated flower, WSe 2 /WO 3-1 (150 °C) rhombic dodecahedron, WSe 2 /WO 3−2 (200 °C) nanorod, were selected to explore their trifunctional electrocatalytic activity towards oxygen reduction, oxygen evolution and hydrogen evolution reactions (OER, ORR, HER). The shape-specific trifunctional electrochemical study was performed over the prepared nanohybrids and it was observed that flower-shaped MoSe 2 /MoO 3-2 nanohybrid having thin and small rod-like petals shows the best performances with smallest OER onset potential=1.1 V, high current density=350 mA cm −2 and small OER Tafel slope of 45 mV/dec. The prepared catalyst also shows very good ORR property with more positive onset potential of 930 mV and Tafel slope of 32 mV/dec. Beside OER and ORR the catalyst shows good HER behavior, due to its small thread like active hydrogen evolution site and exhibit very low onset potential of −0.085 V with low overpotential value of 270 mV and low Tafel slope of 27 mV/dec. The prepared catalyst is free from any methanol cross-over effect and shows good durability and stability, under various extreme conditions. In addition, MoSe 2 /MoO 3-2 based zinc-air battery has also been prepared, which shows an outstanding performance and proves their potential for energy storage and conversion based devices.

Recently, the nanostructured modified molecularly imprinting polymer has created a great attention in research field due to its excellent properties such as high surface to volume ratio, low cost, and easy preparation/handling. Among the nanostructured materials, the carbonaceous material such as 'graphene' has attracted the tremendous attention of researchers owing to their fascinating electrical, thermal and physical properties. In this review article, we have tried to explore as well as compile the role of graphene-based nanomaterials in the fabrication of imprinted polymers. In other words, herein the recent efforts made to introduce selectivity in graphene-based nanomaterials were tried collected together. The major concern of this review article is focused on the sensing devices fabricated via a combination of graphene, graphene@nanoparticles, graphene@carbon nanotubes and molecularly imprinted polymers. Additionally, the combination of graphene and quantum dots was also included to explore the fluorescence properties of zero-band-gap graphene.

A very cost-effective, fast, sensitive and specific imprinted polymer modified electrochemical sensor for the targeted detection, removal and destruction of Escherichia coli bacteria was developed onto the surface of Ag-ZnO bimetallic nanoparticle and graphene oxide nanocomposite. The nanocomposite played a dual role in this work, as a platform for imprinting of bacteria as well as a participated in their laser-light induced photo killing. In terms of sensing, our proposed sensor can detect E. Coli as few as 10CFUmL-1 and capture 98% of bacterial cells from their very high concentrated solution (105CFUmL-1). Similarly to the quantitative detection, we have also investigated the quantitative destruction of E. Coli and found that 16.0cm2 area of polymer modified glass plate is sufficient enough to kill 105CFUmL-1 in the small time span of 5 minutes. The obtained results suggest that our proposed sensor have potential to serve as a promising candidate for specific and quantitative detection, removal as well as the destruction of a variety of bacterial pathogens.

Altering/replacing the rare elements and noble metal like platinum (Pt), iridium (Ir) and ruthenium (Ru) with the earth abundant materials towards the energy devices have extended a lot of attention for the improvement of efficient electrocatalyst. In this chapter, we have focused on the earth abundant electrocatalysts primarily used for overall water splitting, oxygen reduction reaction (ORR) in fuel cells, O2C reduction, N2 reduction and detection of pollutants in water samples. The problem related to the non-noble metals electrocatalysts are their poor electrocatalytic activity, restricted active sites and also small mass transport properties. However, recent studies show that earth abundant materials can be a suitable/efficient candidate for these applications with optimized composition and nano-scale particle size, which will definitely accelerate their catalytic activity. In this chapter, we have focused on all these aspects of earth abundant electrocatalysts (EAEs) and discussed their future perspectives also.

In recent time, nanomaterials have been developed as the most auspicious therapeutic remedy toward the infectious microbes, which cannot be healed through traditional treatments. The ancient age treatments via antibiotic drugs are now failed toward microbes, owing to their heavy and unnecessary high dose consumption by the common people. Now, the microbes have become resistant to these antibiotic medicines, and therefore, the nanomaterials came in light to tackle these rising problems related to microbe infections.

Two-dimensional (2D) materials having fascinating properties, versatility, and a wide range of applications have drawn great interest from researchers. After the discovery of graphene, scientists have discovered various non–graphene-based 2D layered materials, which also have a high surface area, few-atom thickness, and a large number of defect planes and have emerged as the next-generation material. In this chapter, we have comprehensively discussed about the synthesis strategies popularly adopted for the synthesis of 2D nanomaterials. Among the various types of top-down synthesis approaches, chemical exfoliation method is preferred and in the bottom-up synthesis, chemical vapor deposition and wet chemical hydrothermal synthesis have gained interest among the researchers. These methods produce less impurities in the product and give controllable atomic layers in the crystal structure. After discussing about the synthesis practices, we have discussed briefly about the 2D nanomaterials discovered to date and their intriguing physiochemical properties. With their unique properties, they can be used in various applications such as solar cells, sensing, biomedical field, electronic devices, and fuel cells, which are discussed in this chapter. As a concluding remark, the future aspects of 2D nanomaterials are also covered.

This chapter reviews some of the flexible substrate-based sensor, which includes their fabrication method, materials required for their fabrication, outstanding unique properties of them, and their application in health monitoring. The prepared sensors are attached to the human body which detects human biological signals very quickly and precisely for point care diagnosis. The discovery of this type of sensors has led to the early detection of several deadly diseases like cancers, cardiovascular diseases, and respiratory diseases. Flexible substrate-based sensors are extremely lightweight, transparent, deformable, and stretchable. Flexible sensors made the market of portable, sensitive, inexpensive type of sensors to much famous mainly in the field of clinical application that conventional sensors have become very much obsolete and will get worn-out in the near future. Practical application of this flexible substrate-based sensor is further discussed in this chapter which will give an idea of their expansion in the diagnostic field.

Smartphone-based sensors and nanodevices are a popular field for the development of real-time, in-field based diagnoses or applications. Newly launched smartphones have a number of built-in sensor units including accelerometers, wi-fi, high megapixel back and front cameras, Bluetooth, gyroscopes, light sensors, heart rate monitors, fingerprint sensors, touch screens, proximity sensors, pedometers, temperature sensors, microphones, and barometers. These ultra-smartphones are being used for real-time applications in our daily lives. This chapter summarizes the applications of popular smartphone-based nanodevices currently used in various biomedical fields and determination of different metal ions concentration. Smartphone nanodevices are mainly used to determine the presence of metal ions (lead, mercury), anions (chloride), biologically important compounds (cholesterol, albumin), viruses, bacteria, and even single cells. Smartphone detection methods such as colorimetric, fluorescence, electrochemical sensing, luminescence, and even smartphone-based microscopes have been used for the quantitative detection of different analytes. This chapter also discusses the basic working principle of all the aforementioned detection methods, how they are coupled with smartphones, and how they can be applied in biomedical fields.

Nanotechnology associated with particles with nanoscale dimension (typically less than 100 nanometers) exhibit completely different and tempting physicochemical, optical, mechanical, and electromagnetic property from the bulk material from which they are made. Incorporating a large surface area, nanomaterials are prone to be affected by environmental changes, which can decrease their stability as well as their performance. To enlarge the field of application, the functionalization of nanomaterials has been introduced. Surface modification mainly tunes the interaction of the surface entities to overcome major limitations such as inertness, low solubility, and agglomeration in specific solvents. Depending on the application, different functional groups can be introduced on the surface of nanomaterials through covalent or noncovalent bonding to create functionalized nanomaterials with enhanced optical, mechanical, thermophysical, adsorption, and electrical properties in comparison to their parent materials. Thus advanced functionalization techniques of nanomaterials are very beneficial in different industrial applications because of improved production limits, cost reduction, simplification in the procedure, better precision, and sensitivity. A variety of investigations have been carried out on the functionalization of nanomaterials including metal, nonmetal, semiconductor, alloy, and metal oxides for integration into electronics and energy-related products. In this chapter, we discuss recent developments in various electronic, electrical, and energy industries using different types of functionalized nanomaterials. In addition, to review the industrial applications of functionalized nanomaterials we focus on current needs, development status, future scopes, and limitations of this technology through both experimental and theoretical aspects.

Free standing graphene belongs to the pioneering group of carbonaceous nanomaterial and has gained large appreciation in the field storage and conversion of energy. Free standing or self-supported graphene materials are made up of dense graphene sheets arranged in the form of three dimensional structures like foam, films, monoliths, papers, and aerogels with hierarchical porous structure. In last few decades, speedy growth in the binder free graphene based super-capacitors can be credited to their influential properties like flexibility, large surface to volume ratio, high mechanical durability, electrical and thermal conductivity, and light weight. The free standing graphene also delivers us with short and easy diffusion pathway for ions (generated from electrolytes), channels for electron transport and composites with active materials which provide a synergistic effect. This chapter will provide the information about synthesis of free standing graphenes and their recent advancements as the efficient electrode materials for supercapacitors.

Due to depletion of fossil fuels, development of large-scale ground-breaking energy conversion technology like fuel cells, water splitting, air batteries etc. needs pertinent catalyst to ease the process of conversion of chemical energy to electrical energy with greater efficiency in low time consuming. In this chapter, we will discuss the role of self-supported catalyst, which are now trending the era of nanotechnology in electrocatalysis. Self-supported catalyst can be grown on soft substrate, hard substrate or can be free standing. Self-supported electrocatalyst does not needs binder for their attachment on the conductive surface of other electrodes like glassy carbon electrode, platinum electrode, graphite electrode. They have various unique properties like flexible electrode surface, large number of active sites, high electrical conductivity, better catalytic performances, and stability in any pH electrolytic solution. They render much hassle-free electrode synthesis procedure than the powdery electrode material. This chapter mainly focuses on the benefits of using self-supported electrodes in various energy application like water splitting, oxygen reduction reaction (ORR), CO2 reduction reaction, fuel cells. It has been observed that the self-supported electrocatalyst proves to be the superior electrocatalyst in the immense area of electrocatalysis.

Herein, we have developed a photocatalytic, fluorescent bismuth phosphate@graphene oxide (BiPO

In this work, a selective and sensitive non-enzymatic electrochemical glucose sensor was developed using cobalt oxide nanoflowers (NF). Herein, for the first time, shape-specific electrochemical properties of cobalt oxide nanostructures were studied by synthesizing the spherical nanoparticle (NP), porous nanorod (NR) and nanoflower (NF) shapes of cobalt oxide by easy and facile wet-chemical processes. Cobalt oxide nanoflowers showed high surface-to-volume ratio with superior electrocatalytic behavior, and therefore, are more suited for designing a selective and sensitive non-enzymatic glucose sensor. All the as-synthesized samples are characterized using different spectroscopic and microscopic techniques. Prior to sensor fabrication, the nanostructures are further analyzed using voltammetric techniques for the determination of electroactive/real surface area and electrode parameters. The cobalt oxide nanoflowers exhibit maximum electrocatalytic activity owing to the larger exposure area resulting from its unique 3-D hierarchical architecture with interconnected nanosized petals. The influence of supporting electrolyte, electrolyte concentration and applied potential on the electrooxidation of glucose on cobalt oxide nanoflower-modified pencil graphite electrode (NF-PGE) sensor is examined, and the mechanism is explained. The developed amperometric glucose sensor exhibits excellent anti-interfering property and two wide linear ranges of 5 to 60 μM and 0.2 to 3.0 mM, with high sensitivities of 693.02 μA mM−1 cm−2 and 228.03 μA mM−1 cm−2 and detection limits (LOD) as low as 0.04 μM and 0.14 μM, respectively. Furthermore, the practical feasibility of the developed sensor was tested for the quantification of glucose in various commercially available soft drinks, fresh fruit extracts, and human blood samples via standard addition (SA) method.

The present work describes the fabrication of a low-cost, simple, and highly selective analytical method based on the unique combination of fluorescent carbon dots (CDs) and molecularly imprinted polymers (MIPs) for sensitive visual detection of silver ions at trace levels in real samples in both outdoors and at-home. For the first time, fluorescein dye is used as a precursor for the preparation of CDs. The prepared CDs have low toxicity, high stability, good quantum yield, and are free from the common problems (low stability, weak fluorescence intensity, and fast photo-bleaching) of commercially available dyes. The CDs modified MIP (CDs@MIP) has been successfully applied in calligraphy and staining of 3-D crafted papers. In addition, the prepared CDs@MIP has demonstrated the triple-signalling mode trace-level detection of silver ions, in which a simple CDs@MIP solution was sufficient to monitor the presence of silver ions in real and complex matrices with the naked eye, i.e. instrument-free analysis (detection limit = 10.0 μg L−1). The CDs@MIP modified filter-paper strips can be used for the very handy, safe, sensitive, semi-quantitative and rapid detection of silver ions (response time

Like the two sides of a coin, any new invention or discovery also possess their two faces. Similarly, while nanomaterials were identified as a boon in several fields like industrial, medicinal or agriculture; some of them have been also validated as a risk to the environment and living organisms. In this report, we addressed an efficient optical method for the detection of popularly used titanium dioxide nanoparticle (TiO2) by a size-specific imprinted polymer embedded heteroatom-doped carbon nanodots (CNDs) decorated at the surface of the water-soluble magnetic nanoparticle. The CNDs were prepared by an economic and eco-friendly one-step hydrothermal method using a series of Brassicaceae family members (i.e. radish, cabbage, broccoli, and cauliflower). The as prepared CNDs shows very good production (12.8%) and quantum yields (40.7%). The size-specific imprinted polymer is biocompatible and biodegradable in nature and was able to detect the TiO2 nanoparticles with a high selectivity i.e. limit of detection (LOD)=6.88ngL(-1) (S/N=3) and remove the nanoparticle very efficiently. Furthermore, the method was successfully applied for the detection of TiO2 nanoparticles in wastewater, human sera, and cosmetic samples.

The simple, green, cost-effective and environmental friendly technique used by our south-Indian peoples to make their very favourite and world-famous meal i.e. “Idli” was adopted here to prepare the three-dimensional heteroatom-doped graphene foam. The graphene-Idli was first prepared in a domestic microwave oven using heteroatom-doped (boron, nitrogen, sulphur and phosphorous) graphene and rice flour and calcined to produce graphene foam which was used as a metal-free bifunctional catalyst for oxygen evolution (OER) and oxygen reduction (ORR) reactions. The performance of heteroatom-doped foams (nitrogen, sulphur, boron and phosphorous) was studied and it was found that sulphur-doped graphene foam (s-DGF) shows better performance as electrocatalyst, in terms of high BET surface area (499 m2/g), electrochemical surface area (0.271 cm2), high roughness factor (0.690) and high porosity. As a bifunctional electrocatalyst, it possess a lowest onset potential (0.29 V vs Ag/AgCl), highest current density (497 mA cm−2), lowest overpotential (128 mV) and lowest Tafel slope (35.71 mV/dec) for oxygen evolution reaction and an onset potential of (−0.02 V), current density (−125 mA cm−2) and Tafel slope (49.83 mV/dec) for oxygen reduction reaction. The obtained values are best among other reported metal-free electrocatalyst and superior to several metal-based electrocatalysts. The prepared foams were free from any methanol cross-over effect and show a good stability in all the aspect i.e. performance, storage etc. Being a bifunctional catalyst, the S-DGF was successfully implemented for the fabrication of rechargeable zinc-air battery also. This finding offers a straightforward environment-compatible route for synthesizing attractive bifunctional electrocatalyst material as promising candidates for the large-scale commercialization of regenerative fuel cells and rechargeable metal-air batteries. In addition, the proposed metal-free foam based catalyst are able to overcome the multiple disadvantages of the existing electrocatalyst like high cost, poor stability, low selectivity and detrimental environmental effects.

This paper addresses the detailed investigation on the electrochemical activity of TiO2/PVA nanocomposite-modified pencil graphite electrode (TiO2/PVA-PGE) in aqueous KCl medium at room temperature. Herein, we have used ferri/ferrocyanide redox couple as probe molecule and demonstrated the reversibility, surface diffusion ability, stability, and electroactive surface area of TiO2/PVA-PGE. Formation of functional groups, structure, and the morphology of the prepared sample are examined using various characterization techniques. On top of this, the as-modified PGE is used for the first time in the voltammetric detection of potassium ferricyanide in aqueous KCl medium. The developed sensor is sensitive for only ferricyanide molecule and does not show any current response for other interfering compounds such as, ascorbic acid (AA), Uric acid (UA), dopamine (DA), acetaminophen (ACOP), Hydrogen peroxide (H2O2), and 4-nitrophenol (4-NP) within wide linear range of 0.17–33.33 mM with a high order of correlation (0.997) having a detection limit as low as 0.15 μM. Also high sensitivity of 199.34 μA mM−1 cm−2 for oxidation current is obtained. The finding of present paper gives a very clear and concise understanding towards the role of modification on the surface electrochemistry of any bare/unmodified electrode and shows the ample possibility in the application of the prepared TiO2/PVA nanocomposite-modified electrodes for selective electrochemical sensing of cyanometalic compound in the presence of other electroactive molecules.

The continuous elevation in the arsenic levels in groundwater, due to the industrial and human activities has become a threat around the word and more specifically in South Asia. In the areas where the drinking water contains a high level of arsenic, the foremost step is to provide the safe source of drinking water to the common people, at any cost. Herein, a membrane has been fabricated for selective removal of arsenic (III and V) from drinking water with minimum cost. The membrane is synthesized by a unique combination of ‘grafting-from’ and molecular imprinting technologies. The 3D-imprinted membrane is very stable, highly resistant to breakage and biofouling i.e. possess anti-bacterial property in comparison to the conventional membranes. The synthesized membrane exhibits high adsorption capacity with outstanding specific selectivity towards As (III) and As (V). The membrane can be regenerated and reused, several times, without any loss of their binding capacity. The membrane is also applied for removal of arsenic impurities present in the water samples collected from different area of Jharkhand and West Bengal, India and the membrane exhibits 95% removal efficiency.

Herein, we have reported a graphene and multiwalled carbon nanotubes based nanohybrid as an adsorbent for effective and rapid removal of arsenite and arsenate from real water samples. The nanohybrid was prepared by a combination of Eu-doped magnetic graphene oxide and gold nanoparticle functionalized multiwalled carbon nanotube (Eu-MGO/Au@MWCNT). Herein, the dual behavior (i.e. as adsorbent materials and as electro-active sensing materials) of nanohybrid was explored. The resulting nanohybrid shows desirable magnetic property (15000.0 emu g −1 ) with excellent adsorption capacity for As (III) and As (V) i.e. 320.0 mg g −1 and 298.0 mg g −1 , respectively. The proposed nanohybrid also shows very good photocatalytic behavior for oxidation of As (III) to As (V), which can be used as an effective tool for conversion of highly toxic for of arsenic to less toxic one. Additionally, the nanohybrid-modified electrode was applied to detect arsenate and arsenite by cyclic voltammetry and square wave voltammetry technique. The linear concentration range for determination of As (III) and As (V) was found from 0.99 to 100.0 μg L −1 and 2.0 to 85.0 μg L −1 with LOD 0.27 and 0.99 μg L −1 , respectively. The proposed nanohybrid modified electrode was also applied for the determination of arsenic in various water samples collected from differentially populated/industrial areas.

In this work, we have designed an equipment free, single-step, rapid, cost-effective, “in-house”, and “outdoor” kit for visual detection of lead ions (Pb2+) in various real samples viz., soil, water, bacteria, live cells, and solid fruits based on cube-shaped fluorescent carbon dots. The cube-shaped nitrogen-doped carbon dots (CCDs) were prepared using calcein dye as precursor and have potential to be used as better and stable replacement of commercially available dyes. For the visual detection of Pb2+, the color of the CCDs changes from yellowish to brown in solution and a limit of detection (LOD) of 10.0 μg L–1 was obtained for the naked eye. In addition, the same CCD solution was also coated on a filter paper strip to fabricate an easy-to-prepare paper sensor. The paper sensor was used to identify the Pb2+ in real samples which proves their applicability toward in-situ on-site detection. In addition, the prepared strip sensor was successfully implemented for analysis of lead ions inside the solid fruit...

In this paper, we have prepared a stimuli-responsive polymer modified gadolinium doped iron oxide nanoparticle (poly@Gd-MNPs) as cancer theranostic agent. The responsive polymer is composed of the poly(N-isopropyl acrylamide)-co-tyrosine unit, which shows excellent loading for the anti-cancer drug (methotrexate) and stimuli dependent release (change in pH and temperature). The in vitro experiment revealed that the poly@Gd-MNPs exhibited T1-weighted MRI capability (r1=11.314mM(-1)s(-1)) with good in-vitro hyperthermia response. The prepared poly@Gd-MNPs has generated quick heating (45°C in 2min) upon exposure to an alternating magnetic field and able to travel a distance of 35cm in 1min in the presence of an external magnet. The poly@Gd-MNPs shows 86% of drug loading capacity with 70% drug release in first 2h. The cytotoxic assay (MTT) demonstrated that the nanoparticle did not affect the viability of normal human fibroblast and efficiently kill the MCF7 cancer cells in the presence of an external magnetic field. To explore the uptake of poly@Gd-MNPs in the cells, bright field cell imaging study was also performed. This study provides a valuable approach for the design of highly sensitive polymer modified gadolinium doped iron oxide-based T1 contrast agents for cancer theranostics.

In this work, we have reported a new approach on the use of stimuli-responsive molecularly imprinted polymer (MIP) for trace level sensing of alpha-fetoprotein (AFP), which is a well know cancer biomarker. The stimuli-responsive MIP is composed of three components, a thermo-responsive monomer, a pH responsive component (tyrosine derivative) and a highly fluorescent vinyl silane modified carbon dot. The synthesized AFP-imprinted polymer possesses excellent selectivity towards their template molecule and dual-stimuli responsive behavior. Along with this, the imprinted polymer was also explored as `OR' logic gate with two stimuli (pH and temperature) as inputs. However, the non-imprinted polymers did not have such `OR' gate property, which confirms the role of template binding. The imprinted polymer was also used for estimation of AFP in the concentration range of 3.96-80.0 ng mL(-1), with limit of detection (LOD) 0.42 ng mL(-1). The role of proposed sensor was successfully exploited for analysis of AFP in real human blood plasma, serum and urine sample. (C) 2015 Elsevier B.V. All rights reserved.