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By considering the importance of water and its purity, herein, a powerful adsorbent has been developed for the adsorption of two toxic contaminants that commonly exist in water, viz., divalent mercury and hexavalent chromium. The efficient adsorbent, CNTs–PLA–Pd, was prepared by covalent grafting polylactic acid to carbon nanotubes and subsequent deposition of palladium nanoparticles. The CNTs–PLA–Pd could adsorb Hg(II), and Cr(VI) entirely exists in water. The adsorption rate for Hg(II) and Cr(VI) was rapid at initial stage, followed by gradual decrease, and attained the equilibrium. The Hg(II) and Cr(VI) adsorption was perceived within 50 min and 80 min, respectively with CNTs–PLA–Pd,. Further, experimental data for Hg(II) and Cr(VI) adsorption was analyzed, and kinetic parameters were estimated using pseudo–first and second–order models. The adsorption process of Hg(II) and Cr(VI) followed the pseudo–second–order kinetics, and the rate–limiting step in the adsorption was chemisorption. The Weber−Morris intraparticle pore diffusion model revealed that the Hg(II) and Cr(VI) adsorption over CNTs–PLA–Pd occurs through multiple phases. The experimental equilibrium parameters for the Hg(II) and Cr(VI) adsorption were estimated by Langmuir, Freundlich, and Temkin isotherms models. All three models were well suited and demonstrated that Hg(II) and Cr(VI) adsorption over CNTs–PLA–Pd transpires through monolayer molecular covering and chemisorption. [ABSTRACT FROM AUTHOR]

A multimode, dual functional nanomaterial, CNTs-Ag2S, comprised of carbon nanotubes (CNTs) and silver sulfide (Ag2S) nanoparticles, was prepared through the facile hydrothermal process. Before the deposition of Ag2S nanoparticles, hydrophobic CNTs were modified to become hydrophilic through refluxing with a mixture of concentrated nitric and sulfuric acids. The oxidized CNTs were employed to deposit the Ag2S nanoparticles for their efficient immobilization and homogenous distribution. The CNTs-Ag2S could adsorb toxic Cd(II) and completely degrade the hazardous Alizarin yellow R present in water. The adsorption efficiency of CNTs-Ag2S was evaluated by estimating the Cd(II) adsorption at different concentrations and contact times. The CNTs-Ag2S could adsorb Cd(II) entirely within 80 min of the contact time, while CNTs and Ag2S could not pursue it. The Cd(II) adsorption followed the pseudo-second-order, and chemisorption was the rate-determining step in the adsorption process. The Weber−Morris intraparticle pore diffusion model revealed that intraparticle diffusion was not the sole rate-controlling step in the Cd(II) adsorption. Instead, it was contributed by the boundary layer effect. In addition, CNTs-Ag2S could completely degrade alizarin yellow R in water under the illumination of natural sunlight. The Langmuir-Hinshelwood (L-H) model showed that the degradation of alizarin yellow R proceeded with pseudo-first-order kinetics. Overall, CNTs-Ag2S performed as an efficient adsorbent and a competent photocatalyst. [ABSTRACT FROM AUTHOR]

Cancer is a current dreadful disease and the leading cause of death. Next to cardiovascular diseases, cancer is the most severe threat to human life and health. Breast cancer is the most common invasive cancer diagnosed in women. Each year about 2.3 million women are diagnosed with breast cancer. In consideration of the severity of breast cancer, herein we designed the biocompatible nanomaterials, CNTs-HAP and GR-HAP, through grafting of hydroxyapatite (HAP) to carbon nanotubes (CNTs) and graphene (GR) nanosheets. CNTs-HAP and GR-HAP have been tested for their cytotoxicity, growth and motility inhibitory effects, and their effects on the mesenchymal markers. All these demonstrated significant dose-dependent and time-dependent in vitro cytotoxicity against SUM-159 and MCF-7 breast cancer cell lines. The cell viability assay showed that the CNTs-HAP was more effective over SUM-159 cells than MCF-7 cells. It found that the increase in the concentration of GR-HAP has inhibited the clonogenic ability of breast cancer cells. The GR-HAP exhibited a substantial inhibitory effect on the cell motility of SUM-159 cell lines. It was investigated that the expression of vimentin (mesenchymal marker) was majorly reduced in SUM-159 cells by GR-HAP. [ABSTRACT FROM AUTHOR]

An efficient adsorbent, CNTs–PAMAM–Ag, was prepared by grafting fourth-generation aromatic poly(amidoamine) (PAMAM) to carbon nanotubes (CNTs) and successive deposition of Ag nanoparticles. The FT–IR, XRD, TEM and XPS results confirmed the successful grafting of PAMAM onto CNTs and deposition of Ag nanoparticles. The absorption efficiency of CNTs–PAMAM–Ag was evaluated by estimating the adsorption of two toxic contaminants in water, viz., Pb(II) and As(III). Using CNTs–PAMAM–Ag, about 99 and 76% of Pb(II) and As(III) adsorption, respectively, were attained within 15 min. The controlling mechanisms for Pb(II) and As(III) adsorption dynamics were revealed by applying pseudo-first and second-order kinetic models. The pseudo-second-order kinetic model followed the adsorption of Pb(II) and As(III). Therefore, the incidence of chemisorption through sharing or exchanging electrons between Pb(II) or As(III) ions and CNTs–PAMAM–Ag could be the rate-controlling step in the adsorption process. Further, the Weber–Morris intraparticle pore diffusion model was employed to find the reaction pathways and the rate-controlling step in the adsorption. It revealed that intraparticle diffusion was not a rate-controlling step in the adsorption of Pb(II) and As(III); instead, it was controlled by both intraparticle diffusion and the boundary layer effect. The adsorption equilibrium was evaluated using the Langmuir, Freundlich, and Temkin isotherm models. The kinetic data of Pb(II) and As(III) adsorption was adequately fitted to the Langmuir isotherm model compared to the Freundlich and Temkin models. [ABSTRACT FROM AUTHOR]

Herein, we present the rational synthesis of a multimode photothermal agent, NGO–FA–CuS, for the advancement of photothermal therapy of cancer. The hierarchical architecture created in NGO–FA–CuS was attained by the covalent conjugation of folic acid (FA) to nanographene oxide (NGO) through amide bonding, followed by the hydrothermal deposition of CuS nanoflowers. In this approach, instead of mere mixing or deposition, FA was covalently bonded to NGO, which helped in retaining their intrinsic properties after binding and allowed to access them in the resulting hybrid nanostructure. In this specifically designed photothermal agent, NGO–FA–CuS, each component has an explicit task, i.e., NGO, FA and CuS act as the quencher, cancer cell-targeting moiety and photothermal transduction agent, respectively. Prior to the grafting of FA molecules and the deposition of CuS nanoflowers, sulfonic acid groups were introduced into NGO to provide stability under physiological conditions. Under irradiation using a 980 nm laser, NGO–FA–CuS was able to attain a temperature of 63.1 °C within 5 min, which is far beyond the survival temperature for cancer cells. Therefore, the resulting temperature recorded for NGO–FA–CuS was sufficient to induce hyperthermia in cancer cells to cause their death. When coming into contact with cancer cells, NGO–FA–CuS can cause a rapid increase in the temperature of their nucleus, destroy the genetic substances, and ultimately lead to exhaustive apoptosis under illumination using a near-infrared (NIR) laser. An excellent photothermal efficiency of 46.2% under illumination using a 980 nm laser and outstanding cytotoxicity against HeLa, SKOV3 and KB cells were attained with NGO–FA–CuS. Moreover, NGO–FA–CuS displays exceptional persistent photo-stability without photo-corrosiveness. The photothermal effect of NGO–FA–CuS was found to be dependent on its concentration and the power density of the laser source. It was found that its cytotoxicity toward cancer cells was enhanced with an increase in the concentration of NGO–FA–CuS and the incubation period. [ABSTRACT FROM AUTHOR]

The carbon nanotubes (CNTs) have been successfully modified to absorb in near‐infrared (NIR) region by synergetic functionalization with an important biopolymer, polylactic acid (PLA) and subsequent in‐situ deposition of Pd nanoparticles. This process has also extended the absorption ability of Pd nanoparticles towards NIR region apart from its classical absorption in UV and visible regions. Thus fabricated CNTs‐PLA‐Pd demonstrated excellent photothermal effect under exposure to 980 nm laser and significant stability against photo‐bleaching and corrosiveness. A stepwise increment in the photothermal effect of CNTs was attained by covalent grafting of PLA and successive deposition of Pd nanoparticles. The photothermal effect of CNTs‐PLA‐Pd was proportional to its concentration level and photothermal conversion efficiency calculated for CNTs‐PLA‐Pd was 26.5 %. The photothermal effect of CNTs‐PLA‐Pd under illumination to 980 nm laser was higher than that of 808 nm laser. The temperature attained during photothermal effect for CNTs‐PLA‐Pd was beyond 60 °C, which far exceeds the temperature survival level of cancer cells. Overall, the rational integration of CNTs, PLA and Pd nanoparticles in CNTs‐PLA‐Pd by reported strategy could offer a suitable avenue for advancement of cancer therapy. [ABSTRACT FROM AUTHOR]

Naturally available diatomaceous earth (DE) microparticles are ideal candidates for drug delivery due to their excellent features like biocompatibility, non-toxicity, porosity, high surface area and ease of surface modification. On the other hand, they have some limitations, especially in drug delivery applications, such as poor drug loading capacity and a very high initial burst release. In order to address these drawbacks, we have surface modified the diatoms with silica xerogel, which forms a novel hybrid material. The modification process was carried out by a facile sol–gel method, the silica xerogel decorated DE microparticles were extensively characterized by SEM, BET, ATR-IR spectroscopy and XRD in order to confirm the covalent linkage of the new material on the surface of the DE microparticles. The prepared hybrid material DE-XER (xerogel) acts as a pH-sensitive micro drug carrier for diclofenac sodium (DS) drug. The results indicate that surface modification plays a critical role, enhancing the drug loading capacity in comparison with neat DE microparticles, achieving effective controlled release. Furthermore, the obtained drug release data were fitted to the zero order model to understand the drug release mechanism. [ABSTRACT FROM AUTHOR]

A robust, near-infrared (NIR) active photothermal agent, CNTs-PAMAM/G4-CdS, is designed by covalent grafting of fourth generation poly(amidoamine) (PAMAM) to carbon nanotubes (CNTs) and successive deposition of cadmium sulfide (CdS) nanocrystallites. The systematic advancement in photothermal effect of CNTs was achieved by grafting of first, second, third, and fourth generation PAMAM through the repeated process of Michael’s addition. The subsequent deposition of CdS nanocrystallites over fourth generation PAMAM grafted CNTs has further improved the photothermal effect (PTE) of CNTs. The photothermal effect of CNTs-PAMAM/G4-CdS was accessed by illuminating with 980 nm NIR laser. During measurement of PTE, maximum temperature attained by CNTs-PAMAM/G4-CdS was 64.1 °C which far exceeds the survival temperature of cancer cells. The photothermal conversion efficiency estimated for CNTs-PAMAM/G4-CdS was 32%, which is higher than the value reported for popular gold and copper based photothermal agents. Apart from its outstanding photothermal effect, CNTs-PAMAM/G4-CdS possessed excellence in both antiphoto-bleaching and antiphoto-corrosiveness. [ABSTRACT FROM AUTHOR]

Pristine aluminum (Al) has received great deal of attention on fabrication of nanoporous anodized alumina (NAA) with arrays of nanosized uniform pores with controllable pore sizes and lengths by the anodization process. There are many applications of NAA in the field of biosensors due to its numerous key factors such as ease of fabrication, high surface area, chemical stability and detection of biomolecules through bioconjugation of active molecules, its rapidness, and real-time monitoring. Herein, we reviewed the recent trends on the fabrication of NAA for high sensitive biosensor platforms like bare sensors, gold coated sensors, multilayer sensors, and microfluidic device supported sensors for the detection of various biomolecules. In addition, we have discussed the future prospectus about the improvement of NAA based biosensors for the detection of biomolecules. [ABSTRACT FROM AUTHOR]

A single step process for the synthesis of size-controlled silver nanoparticles has been developed using a bifunctional molecule, octadecylamine (ODA). Octadecylamine complexes to Ag + ions electrostatically, reduce them, and subsequently stabilizes the nanoparticles thus formed. Hence, octadecylamine simultaneously functions as both a reducing and a stabilizing agent. The amine-capped nanoparticles can be obtained in the form of dry powder, which is readily redispersible in aqueous and organic solvents. The particle size, and the nucleation and growth kinetics of silver nanoparticles could be tuned by varying the molar ratio of ODA to AgNO 3 . The UV–vis spectra of nanoparticles prepared with different concentrations of ODA displayed the well-defined plasmon band with maximum absorption around 425 nm. The formation of silver metallic nanoparticles was confirmed by their XRD pattern. The binding of ODA molecule on the surface of silver has been studied by FT-IR and NMR spectroscopy. The formation of well-dispersed spherical Ag nanoparticles has been confirmed by TEM analysis. The particle size and distribution are found to be dependent on the molar concentration of the amine molecule. Open aperture z-scans have been performed to measure the nonlinearity of Ag nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract: Herein we report the design of antimicrobial nanohybrids, f-MWCNTs-CdS and f-MWCNTs-Ag2S developed by covalent grafting of cationic hyperbranched dendritic polyamidoamine (PAMAM) onto multiwalled carbon nanotubes (MWCNTs) and successive deposition of CdS and Ag2S quantum dots (QDs). The CdS and Ag2S QDs were in situ deposited on PAMAM grafted MWCNTs instead of anchoring the pre-synthesized QDs. The fourth generation, amine terminated hyperbranched PAMAM was grafted on MWCNTs, which was achieved through repetitive reactions of Michael addition of methylmethacrylate to the surface amino groups and amidation of terminal ester groups with ethylenediamine. The covalent grafting of PAMAM onto MWCNTs and the consecutive conjugation of CdS and Ag2S QDs were characterized using Fourier transform infrared spectroscopy, elemental analysis, powder X-ray diffraction, Raman spectroscopy, transmission electron microscopy and energy dispersive spectroscopy. The antibacterial activity of f-MWCNTs-CdS and f-MWCNTs-Ag2S nanohybrids was evaluated against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus and the results were compared with the activity of carboxylated MWCNTs, PAMAM grafted MWCNTs, PAMAM dendrimer, and CdS and Ag2S QDs. It was found that the germicidal action of MWCNTs was enhanced by grafting of PAMAM, which was further improved with immobilization of CdS and Ag2S QDs. [Copyright &y& Elsevier]

Abstract: Herein a facile hydrothermal approach is used to construct carbon coated TiO2 nanoparticles employing dextrose as the source of carbon. The procedure is operated at a low temperature of 200°C. Fourier infrared spectroscopy demonstrated the successful coating of carbon on TiO2 nanoparticles. The phase composition of TiO2 and carbon coated TiO2 nanoparticles were studied using X-ray diffraction and the surface morphology was analyzed by scanning and transmission electron microscopy. The existence of carbon coating on TiO2 nanoparticles was revealed by thermogravimetric analysis through different thermograms exhibited for TiO2 and carbon coated TiO2 nanoparticles. The reported method offers a simple and efficient approach for production of carbon coated TiO2 nanoparticles. [Copyright &y& Elsevier]

Abstract: Two novel ternary nanocatalysts, f-MWCNTs-CdS and f-MWCNTs-Ag2S were successfully constructed by covalent grafting of fourth generation (G4) hyperbranched, crosslinked poly(amidoamine) (PAMAM) to carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) and subsequent deposition of CdS or Ag2S quantum dots (QDs). The structural transformation, surface potential, and morphology of functionalized MWCNTs (f-MWCNTs) and nanocatalysts were characterized by UV–vis spectrophotometer, Fourier transform infrared spectroscopy, powder X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, scanning electron microscopy and energy dispersive spectroscopy. Transmission electron microscopy reveals the effective anchoring of QDs on f-MWCNTs. The catalytic activity of nanocatalysts was evaluated by photodegradation of methyl orange under illumination of UV light. The coupling of MWCNTs, PAMAM and CdS or Ag2S QDs significantly enhanced the catalytic efficiency of nanocatalysts. The rate constants for degradation of methyl orange in presence of nanocatalysts were calculated using the Langmuir–Hinshelwood model. Overall, the excellence in photodegradation was accomplished by hybridizing f-MWCNTs with CdS or Ag2S QDs. [Copyright &y& Elsevier]

Abstract: Herein a simple and effective approach is introduced to functionalize single walled carbon nanotubes (SWCNTs) by in-situ grafting of hydroxyapatite (HA). The pristine SWCNTs were chemically activated through introduction of carboxylic groups on their surfaces by refluxing in the mixture of H2SO4 and HNO3. The resulting carboxylated SWCNTs were further utilized for grafting of HA. The Fourier transform infrared and Raman spectroscopic studies demonstrated the formation of HA and its grafting over SWCNTs. The phase composition of HA and existence Ca2+ and PO4 3− ions were studied using X-ray diffraction and energy dispersive X-ray analyses, respectively. The surface morphology of functionalized SWCNTs was analyzed using scanning electron microscopy and transmission electron microscopy. Thermogravimetric analysis confirmed the existence of HA on SWCNTs by exhibiting different thermogram for pure HA and functionalized SWCNTs. Overall, this method produced uniform grafting of low crystalline HA on carboxylated SWCNTs with strong interfacial bonding. [Copyright &y& Elsevier]

The synthesis of polyaniline (PANI) nanospheres using a simple template-free method is described. The polymerization of aniline in aqueous medium was accomplished using ammonium persulfate without any protonic acid. The UV-visible spectrum of the PANI nanospheres displayed the characteristic absorption peak of the π-π* transition of the benzenoid ring at 355 nm. The oxidation state of the PANI nanospheres was identified with Fourier transform infrared spectroscopy by comparing the two bands at 1582 cm−1 (ring stretching in quinoid unit) and 1498 cm−1 (ring stretching in bezenoid unit). X-ray diffraction patterns demonstrated the low crystallinity of the PANI nanospheres. The morphology of the PANI nanospheres was spherical and their mean diameter was found to be in the range 3-12 nm. The thermal behavior of the PANI nanospheres was studied using thermogravimetric analysis. The effect of doping of HCl and H2SO4 on the PANI nanospheres was studied by measuring the current as a function of time of exposure. A high electrical conductivity of 6 × 10−2 S cm−1 was obtained for the PANI nanospheres doped with 100 ppm HCl, their optimum doping state. Copyright © 2011 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The title compound, [Er(C5H7O2)3(C12H8N2)], is a mixed-ligand metal–organic precursor for chemical vapour deposition, with the Er atom being eight-coordinate. The coordination polyhedron, described as a distorted square anti­prism, is formed by three bidentate (chelating) acetyl­acetonate residues and a phenanthroline ligand in the apical positions. Mol­ecular assembly via C—H⋯O hydrogen bonds generates a sheet structure in the ac plane. Weak co-operative C—H⋯π inter­actions form mol­ecular dimers and contribute to the stability of the inter­sheet packing. The supra­molecular assembly contains voids which form hydro­phobic porous channels, surrounded by a cluster of dimers. [ABSTRACT FROM AUTHOR]

Herein, we report the in situ polymerization of 1,5-diaminonaphthalene (15DAN) and 1,4-diaminoanthraquinone (14DAA) on the surface of reduced graphite oxide (RGO). Synthesized RGO-P15DAN and RGO-P14DAA were characterized by FTIR, Raman, SEM, TGA and XRD. The adsorption capacity and adsorptivity of the synthesized composites were investigated by Atomic Absorption Spectroscopy (AAS) using 100 ppm aqueous solution of Pb 2+ ions. Further, we compared the results of the composites with those of poly 1,5-(diaminonaphthalene) (P15DAN), poly 1,4-(diaminoanthraquinone) (P14DAA), RGO, graphite oxide (GO) and graphite. Among the tested adsorbents, RGO-P15DAN demonstrated the high adsorptivity. [ABSTRACT FROM AUTHOR]

In the present study, hydroxyapatite (HA) was successfully grafted to carboxylated carbon nanotubes (CNTs) and graphene nanosheets. The HA grafted CNTs and HA-graphene nanosheets were characterized using FT-IR, TGA, SEM and X-ray diffraction. The HA grafted CNTs and graphene nanosheets (CNTs-HA and Gr-HA) were further used to examine the proliferation and differentiation rate of temperature-sensitive human fetal osteoblastic cell line (hFOB 1.19). Total protein assays and western blot analysis of osteocalcin expression were used as indicators of cell proliferation and differentiation. Results indicated that hFOB 1.19 cells proliferate and differentiate well in treatment media containing CNTs-HA and graphene-HA. Both CNTs-HA and graphene-HA could be promising nanomaterials for use as scaffolds in bone tissue engineering. [ABSTRACT FROM AUTHOR]

The title compound, [Ni(C8H13O3)2(C5H5N)2]·C6H6, a potential metal–organic chemical vapour deposition (MOCVD) precursor, crystallizes with half a molecule of the complex and half a molecule of benzene in the asymmetric unit, both molecules being centrosymmetric. The Ni atom is at the origin (0, 0, 0), while the centroid of the benzene solvent molecule is at another centre of symmetry (0,  ,  ). The Ni atom has a distorted octahedral environment, with four O atoms from the bidentate tert-butyl-3-oxobutanoate ligand units in the axial positions and the two N atoms of the pyridine ligands at the apical positions. C—H...π contacts [3.021 (4) Å] between solvent benzene and the pyridine ligand, along with π–π stacking interactions [3.896 (1) Å] between adjacent pyridine ligands, result in a packing motif along the c axis. [ABSTRACT FROM AUTHOR]

In the title complex, [Al(C8H13O3)3], a potential metal-organic chemical vapour deposition (MOCVD) precursor, three bidentate ligand mol­ecules are bound to the metal atom, forming an octa­hedral geometry. Two non-planar six-membered chelate rings adopt screw-boat conformations, while the third ring has a conformation that lies about halfway between an envelope and a screw-boat. [ABSTRACT FROM AUTHOR]

• Naturally available 3D diatoms (DE) combined with MIL100(Fe) to form MIL100(Fe)-DE hybrid materials. • MIL100(Fe)-DE as drug carrier controlled the drug release up to 23 days. • MIL100(Fe)-DE used as heterogeneous Fenton's catalysis showed 99% of MB degradation efficiency. • MIL100(Fe)-DE showed Pb2+ removal of 96.45% efficiency and high adsorption capacity of 155 mg/g with excellent reusability. • MIL100(Fe)-DE explored for various dye removal applications with removal efficiency of 98, 96, 76 and 75% respectively. Metal-organic frameworks (MOFs) emerged as one of the promising functional materials for broad applications. To improve the sustainability of their synthetic route and extend their applications are still demanding and challenging task. Herein, to address this problem, we report practical use of "eco-friendly" approach to create new type of hybrid materials by combining MOFs with naturally available hierarchical diatom biosilica (DE) acts as 3D porous scaffolds. This combination of high surface area, an unique 3D diatom architecture with 2D MOFs structure with specific chemical functionalities –OH, –COOH and Fe atoms confined in MIL-100(Fe)-DE hybrid materials and explored for a wide range of applications like drug delivery, catalyst support and environmental adsorbents. To prove drug delivery application for MIL-100(Fe)-DE, isoniazid (INH) anti-TBC (tuberculosis) drug is selected as typical drug model showing an enhanced drug loading capacity of 9.6 ± 1.6% and an extended in vitro controlled drug release performances over 23 days. This is significant improvement of short drug release characterstics and biological half life of INH (1–4 h) that limits to rich full therapeutic benefits for treatment of TBC. A heterogeneous Fenton's catalysis study of MIL-100(Fe)-DE showed a rapid degradation of Malachite green (MG) dye within 60 min with degradation efficiency of 99.02 ± 1.3%. To prove environment remediation performances at 25 °C and in pH 6, MIL-100(Fe)-DE displayed efficient removal of Pb2+ with removal efficiency of 96.45 ± 2.1%, high adsorption capacity of 155 mg/g and the improved partition co-efficient (PC) was 87.32 mg.g−1.µM−1 for Pb2+ of (50 mg/L) with excellent reusability. Finally, MIL-100(Fe)-DE hybrid was tested for the removal of cationic dyes such as methylene blue (MB), rhodamine B (RhB) and anionic dyes like congo red (CR) and erichrome black T (EBT) showing 96.10 ± 1.3, 75.11 ± 1.95, 98.11 ± 1.7 and 76 ± 1.88% of removal efficiency respectively. [ABSTRACT FROM AUTHOR]

A key auxiliary role of photothermal effect (PTE) in the enhancement of photocatalytic activity under illumination to near-infrared (NIR) radiations has been experimentally revealed. It was found that the photoexcitation of electrons, required for the process of photocatalysis does not occur in presence of NIR radiations alone without the support of both UV and visible radiations. Herein, a binary heterogeneous nanophotocatalyst, GR-ZnO was fabricated by a novel approach using hydrothermal process. In which ZnO nanotrapezoids were deposited over the surfaces of graphene nanosheets. In the reported unique approach, reduction of graphene oxide to graphene has been accomplished using water by an entirely alternative mechanism compared to traditional reduction processes those employ the hazardous reducing agents. Thus produced GR-ZnO photocatalyst has exhibited the excellence in rapid degradation of industrially voluntarily employing perilous dye, methyl orange. It is explored that PTE is mainly responsible for the rapid degradation of methyl orange transpired under illumination to NIR laser. Further, it has been established that PTE could not emerge with NIR radiations alone without the support of both UV and visible radiations. In consideration of its importance, PTE of GR-ZnO nanocatalyst has been revealed and compared with its individual components, viz., graphene and ZnO. Moreover, the photothermal conversion efficiency of GR-ZnO nanocatalyst was evaluated. Overall, the excellent catalytic activity found in GR-ZnO nanocatalyst was accounted for its decreased band gap, transpired by hybridization of ZnO with graphene could efficiently prevent the recombination of photo-generated charge carriers. In addition, admired catalytic activity of GR-ZnO nanocatalyst was attributed to improved optical absorption and enhancement in the adsorption affinity to methyl orange molecules.

Herein, we report the modulation of ZnO for enhancement of its ability toward plasmonic absorption of near-infrared (NIR) photons through coupling of graphene (GR). The reported modification led GR-ZnO to be a promising photocatalyst by the complete removal of poisonous and nonvolatile potassium cyanide from water. The photocatalytic degradation of cyanide was revealed by exposing it to NIR laser and comparing with the rate of UV, visible, and sunlight using their apparent reaction rate constants derived from the Langmuir-Hinshelwood model. The heteronanostructured GR-ZnO promoted rapid photo-oxidation of cyanide under illumination with NIR laser rather than UV, visible, and sunlight. It was assessed that the photothermal effect (PTE) is the main cause for higher catalytic efficiency of GR-ZnO in the presence of NIR radiations. Except for the NIR radiations, GR-ZnO does not show any indication of PTE by irradiating with UV, visible, or sunlight. On account of its significance, the PTE of GR-ZnO in KCN solution was evaluated and compared with its individual components viz., GR and ZnO upon exposure to a 980 nm laser system. Furthermore, it has been revealed that the PTE of GR-ZnO was proportional to its concentration. In addition to its effectiveness in the degradation of cyanide, GR-ZnO retained its special structure and exhibited an outstanding photostability after its repeated use in three successive cycles., Competing Interests: The authors declare no competing financial interest.

The synthesis of polyaniline (PANI) nanospheres by a simple template-free method has been described. The polymerization of aniline in aqueous medium was accomplished using ammonium persulfate without any protonic acid. The UV-vis spectrum of PANI nanospheres displayed the characteristic absorption peak of π-π* transition of the benzenoid ring at 355 nm. The oxidation state of PANI nanospheres was identified with FT-IR spectroscopy by comparing the two bands at 1582 (ring stretching in quinoid unit) and 1498 cm(-1) (ring stretching in bezenoid unit). The X-ray diffraction patterns demonstrated the low crystalline nature of PANI nanospheres. The morphology of PANI nanospheres was spherical and the mean diameter of nanospheres was found in the range of 3-12 nm. The thermal behavior of PANI nanospheres was studied by thermogravimetric analysis. The effect of doping of HCl and H(2)SO(4) on PANI nanospheres was studied by measuring the current as a function of time of exposure. The high electrical conductivity of 6×10(-2) S cm(-1) was obtained for PANI nanospheres at their optimum doping state by 100 ppm HCl.