Fabrication of Carbon Nanofiber Incorporated with CuWO4 for Sensitive Electrochemical Detection of 4-Nitrotoluene in Water Samples.

In the current work, copper tungsten oxide (CuWO4) nanoparticles are incorporated with carbon nanofiber (CNF) to form CNF/CuWO4 nanocomposite through a facile hydrothermal method. The prepared CNF/CuWO4 composite was applied to the electrochemical detection of hazardous organic pollutants of 4-nitrotoluene (4-NT). The well-defined CNF/CuWO4 nanocomposite is used as a modifier of glassy carbon electrode (GCE) to form CuWO4/CNF/GCE electrode for the detection of 4-NT. The physicochemical properties of CNF, CuWO4, and CNF/CuWO4 nanocomposite were examined by various characterization techniques, such as X-ray diffraction studies, field emission scanning electron microscopy, EDX-energy dispersive X-ray microanalysis, and high-resolution transmission electron microscopy. The electrochemical detection of 4-NT was evaluated using cyclic voltammetry (CV) the differential pulse voltammetry detection technique (DPV). The aforementioned CNF, CuWO4, and CNF/CuWO4 materials have better crystallinity with porous nature. The prepared CNF/CuWO4 nanocomposite has better electrocatalytic ability compared to other materials such as CNF, and CuWO4. The CuWO4/CNF/GCE electrode exhibited remarkable sensitivity of 7.258 µA µM-1 cm-2, a low limit of detection of 86.16 nM, and a long linear range of 0.2-100 µM. The CuWO4/CNF/GCE electrode exhibited distinguished selectivity, acceptable stability of about 90%, and well reproducibility. Meanwhile, the GCE/CNF/CuWO4 electrode has been applied to real sample analysis with better recovery results of 91.51 to 97.10%.

Hexagonally close-packed three-dimensional nano-flower entrapped on a heteroatom doped carbon sheets: A sensitive electro-catalyst to determine sulfonamide in environmental samples.

Sulfamethazine (SMZ) is one of the antibiotics frequently found with low concentrations in water bodies including drinking water sources and foodstuffs contamination, which affects the environmental ecosystem and humans. Therefore, the detection of SMZ is necessary to protect the biosphere. This work provides an investigation of the SMZ oxidation process using the electrochemical method by hydrothermally synthesized Barium doped Zinc oxide (BZO) with nitrogen and boron-doped reduced graphene oxide (NBRGO). The BZO/NBRGO composite was characterized using FESEM, EDAX, HR-TEM, Raman-spectroscopy, XRD, and XPS. Further, an electrochemical investigation has also made use of EIS, CV, and DPV. The limit of detection (LOD) of the SMZ has been found 0.003 µM with high sensitivity of 12.804 µA µM-1 cm-2 and a linear range (0.01-711 µM). Additionally, the repeatability, reproducibility, and stability of the BZO/NBRGO electrode have an excellent outcome compared with other electrodes. These prepared BZO/NBRGO electrodes have been used for the determination of SMZ in milk and water sample with acceptable recoveries.

Deep Eutectic Solvent-Assisted Synthesis of a Strontium Tungstate Bifunctional Catalyst: Investigation on the Electrocatalytic Determination and Photocatalytic Degradation of Acetaminophen and Metformin Drugs.

In this work, we propose a modified solid-state approach for the sustainable preparation of a SrWO4 bifunctional catalyst using thymol-menthol-based natural deep eutectic green solvents (NADESs). Various spectroscopic and morphological techniques analyzed the as-synthesized SrWO4 particles. Acetaminophen (ATP) and metformin (MTF) were selected as the model drug compounds. The electrochemical detection and photocatalytic degradation of ATP and MTF upon ultraviolet-visible (UV-vis) light irradiation in the presence of as-prepared SrWO4 particles as an active catalyst are examined. The present study displayed that the proposed catalyst SrWO4 has enhanced catalytic activity in achieving the optimum experimental conditions, and linear ranges of ATP = 0.01-25.90 µM and MTF = 0.01-25.90 µM, a lower limit of detection (LOD) value (ATP = 0.0031 µM and MTF = 0.008 µM), and higher sensitivity toward ATP and MTF determination were obtained. Similarly, the rate constant was found to be k = ATP = 0.0082 min-1 and MTF = 0.0296 min-1 according to the Langmuir-Hinshelwood model, benefitting from the excellent synergistic impact of the SrWO4 catalyst toward the photocatalytic degradation of the drug molecule. Hence, this work offers innovative insights into the applicability of the as-prepared SrWO4 bifunctional catalyst as an excellent functional material for the remediation of emerging pollutants in water bodies with a recovery range of 98.2-99.75%.

Effect of hydrophobicity and size of the ligands on the intercalative binding interactions of some metallo-surfactants containing π-conjugated systems with yeast tRNA.

The intercalative yeast t-RNA binding behavior of some metallo-surfactant complexes, Co(ip)2(TA)2](ClO4)3 (1) and [Co(dpq)2(TA)2](ClO4)3 (2) where TA = Tetradecylamine (Myristylamine), ip = imidazo[4,5-f][1,10]phenanthroline and dpq = dipyrido[3,2-d:2'-3'-f]quinoxaline containing π-conjugated systems (both below and above critical micelle concentration) have been investigated by means of absorption spectral titration, competitive binding, circular dichroism, cyclic voltammetry, and viscometry measurements. Absorption spectral titration results implicate yeast tRNA has significant effects on the binding behaviors of two surfactant complexes via intercalative mode showed a significant absorption band of hypochromicity with red shift. The intrinsic binding constant values below and above CMC were determined as Kb = 6.12 × 105 M-1, 2.31 × 106 M-1, for complex (1) and 7.23 × 105 M-1, 3.57 × 106 M-1, for complex (2). In both sets of complexes (1) and (2), the complexes bind more strongly to yeast tRNA in the above critical micelle concentration can be hydrophobic and confirm intercalation. Competitive displacement studies confirmed that complexes bind to yeast tRNA via intercalative mode. Cyclic voltammetry studies suggest the increasing amounts of yeast tRNA, the cathodic potential Epc for the two complexes shows a positive shift in peak potential indicated the process of binding via intercalation. These observations were further validated by CD, and hydrodynamic measurements. All these studies suggesting that a surfactant complex binds to yeast tRNA appear to be mainly intercalative because of hydrophobicity due to extending aromaticity of the π system of the ligand and planarity of the complex has a significant effect on tRNA binding affinity increasing in the order of complexes containing ligands ip < dpq.Communicated by Ramaswamy H. Sarma.

Metallo-Surfactant assisted silver nanoparticles: A new approach for the colorimetric detection of amino acids.

In this study, we report a new class of metallo-surfactant assisted silver nanoparticle produced by reduction process via AgNO3 solution and extract of Turnera Subulata (TS) in aqueous which act as reducing and metallo-surfactant [Co(ip)2(C12H25NH2)2](ClO4)3 (ip = imidazo[4,5-f][1,10]phenanthroline) act as stabilizing agent. In this study the silver nanoparticles produced using Turnera Subulata extract has showed yellowish brown color formation and an absorption peak at 421 nm signaling the biosynthesis of silver nanoparticles. The presence of functional groups in the plant extracts were identified by FTIR analysis. In addition, the effects of ratio, changing the concentration of the metallo surfactant, TS plant leave extract, metal precursors, and pH of the medium have been investigated on the scale of the Ag nanoparticles. Spherical shaped, crystalline in nature and ∼50 nm sized particles were recorded using TEM and DLS analysis. Furthermore, the mechanistic insights into cysteine and dopa detection by silver nanoparticles were investigated using HR-TEM analysis. This induces aggregation in stable silver nanoparticles owing to selective and strong interaction of -SH group of cysteine with silver nanoparticle surface. The biogenic Ag NPs are found to be highly sensitive to amino acids of dopa and cysteine with the diagnosis maximum for both amino acids as low as 0.9 µM (dopa) and 1 µM (cysteine) under optimized conditions.

Fabrication of ZnWO4/Carbon Black Nanocomposites Modified Glassy Carbon Electrode for Enhanced Electrochemical Determination of Ciprofloxacin in Environmental Water Samples.

The major problem facing humanity in the world right now is the sustainable provision of water and electricity. Therefore, it is essential to advance methods for the long-term elimination or removal of organic contaminants in the biosphere. Ciprofloxacin (CIP) is one of the most harmful pollutants affecting human health through improper industrial usage. In this study, a zinc tungsten oxide (ZnWO4) nanomaterial was prepared with a simple hydrothermal synthesis. The ZnWO4/Carbon black nanocomposites were fabricated for the determination of CIP. The nanocomposites were characterized by field emission scanning electron microscopy, energy dispersion X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. Electrochemical studies were done using cyclic voltammetry and differential pulse voltammetry methods. Based on the electrode preparation, the electrochemical detection of CIP was carried out, producing exceptional electrocatalytic performance with a limit of detection of 0.02 µM and an excellent sensitivity of (1.71 µA µM-1 cm-2). In addition, the modified electrode displayed great selectivity and acceptable recoveries in an environmental water sample analysis for CIP detection of 97.6% to 99.2%. The technique demonstrated high sensitivity, selectivity, outstanding consistency, and promise for use in ciprofloxacin detection. Ciprofloxacin was discovered using this brand-new voltammetry technique in a water sample analysis.

'On and Off' intercalative binding behaviour of double chain surfactant cobalt(III) complex containing 2, 2'-bipyridyl ligand in ß-Cyclodextrin: A detail approach on Host-guest inclusion of surfactant cobalt(III) complex and CT-DNA binding in micro-heterogeneous medium.

The binding interaction of surfactant cobalt(III) complex, cis-[Co(bpy)2(HA)2](ClO4)3, in which bpy is 2,2-bipyridine and HA is hexadecylamine or cetylamnine with DNA was through intercalative mode via the long aliphatic chains present in the ligands. The binding was investigated by various techniques, electronic absorption, fluorescence spectroscopy, circular dichroism (CD), cyclic voltametry (CV) and viscosimetry measurements. The spectroscopic studies together with cyclic voltammetry and viscosity experiments support that the surfactant cobalt(III) complex binds to calf thymus DNA by intercalation through the aliphatic chain present in the complex into the base pairs of DNA. The presence of bipyridine ligand with larger π-frame work may also enhance intercalation. UV-vis., spectrum showed 4 nm bathochromic shift of the absorption band at 352 nm along with significant hypochromicity for the absorption band of the complex. The intrinsic binding constants(at below and above CMC are Kb = 2.41 × 105M-1, Kb = 3.12 × 106M-1 respectively) is more in keeping with intercalators and suggests this binding mode. The viscosity measurements showed that the surfactant cobalt(III) complex-DNA interaction can be hydrophobic and confirm intercalation. Moreover, the complex induced detectable changes in the CD spectrum of CT-DNA. Competitive binding study with ethidium bromide (EB) shows that the surfactant complex exhibits the ability to displace the DNA-bound EB indicating that the complex binds to DNA in strong competition with EB for the intercalative binding site. Also, CV results confirm this mode because, with increasing the CT-DNA concentration, shift to higher potential was observed. Besides the effect of binding of surfactant cobalt(III) complex to DNA in presence of ß-cyclodextrin has also studied. This binding of the surfactant cobalt(III) complex in presence of ß-cyclodextrin medium has been prevented (at below and above CMC are Kb = 5.45 × 104M-1, Kb = 6.92 × 105M-1 respectively) due to the incorporation of the aliphatic chains into the cavity of ß-cyclodextrin. In presence of ß-cyclodextrin the binding occur through surface and (or) groove binding can be attributed to the inclusion of the long aliphatic chain that is present in one of the ligands into cyclodextrin.

Gadolinium molybdate decorated graphitic carbon nitride composite: highly visualized detection of nitrofurazone in water samples.

In this work, a graphitic carbon nitride/gadolinium molybdate (g-C3N4/Gd2MoO6) composite manufactured glassy carbon electrode (GCE) was used to detect nitrofurazone (NFZ) at the trace level. A quick and inexpensive electrochemical sensor for NFZ analysis is described in this paper. The material structure and properties were determined by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and transmission electron microscopy. The GCE/g-C3N4/Gd2MoO6 electrode was studied using cyclic voltammetry and amperometry. The electrocatalytic studies of the GCE/g-C3N4/Gd2MoO6 electrode showed significantly improved detection of NFZ. The electrocatalytic studies of the GCE/g-C3N4/Gd2MoO6 electrode was significantly improved for the detection of NFZ than bare GCE, GCE/g-C3N4, and GCE/Gd2MoO6 modified electrodes. The linear response and the detection limit of NFZ were 0.006 µM (S/N = 3) and 0.02-2000 µM, respectively. The electrode sensitivity was identified as 2.057 µA µM-1 cm-2 under ideal experimental conditions. The modified electrode was able to detect NFZ even when there were 500-fold as many interfering ions present. The practical applicability of the electrode was tested in a variety of water samples, with satisfactory results. Overall, the NFZ sensor demonstrated satisfactory repeatability, stability, and reproducibility. Meanwhile, it has proven to be a reliable, stable, and practical platform for the analysis of NFZ in various water samples, with acceptable recoveries.

States of Aggregation and Phase Transformation Behavior of Metallosurfactant Complexes by Hexacyanoferrate(II): Thermodynamic and Kinetic Investigation of ETR in Ionic Liquids and Liposome Vesicles.

Electronic absorption spectroscopy was used to study the ETR of surfactant-cobalt(III) complexes containing imidazo[4,5-f][1,10]phenanthroline, dipyrido[3,2-d:2'-3'-f]quinoxaline and dipyrido[3,2-a:2',4'-c](6,7,8,9-tetrahydro)phenazine ligands by using ferrocyanide ions in unilamellar vesicles of dipalmitoylphosphotidylcholine (DPPC) and 1-butyl-3-methylimidazolium bromide ((BMIM)Br), at different temperatures under pseudo-first-order conditions using an excess of the reductant. The reactions were found to be second-order and the electron transfer is postulated as occurring in the outer sphere. The rate constant for the electron transfer reactions was found to increase with increasing concentrations of ionic liquids. Besides these, the effects of surfactant complex ions on liposome vesicles in these same reactions have also been studied on the basis of hydrophobicity. We observed that, below the phase transition temperature, there is an increasing amount of surfactant-cobalt(III) complexes expelled from the interior of the vesicle membrane through hydrophobic effects, while above the phase transition temperature, the surfactant-cobalt(III) complexes are expelled from the interior to the exterior surface of the vesicle. Kinetic data and activation parameters are interpreted in respect of an outer-sphere electron transfer mechanism. By assuming the existence of an outer-sphere mechanism, the results have been clarified based on the presence of hydrophobicity, and the size of the ligand increases from an ip to dpqc ligand and the reactants become oppositely charged. In all these media, the ΔS# values are recognized as negative in their direction in all the concentrations of complexes employed, indicative of a more ordered structure of the transition state. This is compatible with a model in which these complexes and [Fe(CN)6]4- ions bind to the DPPC in the transition state. Thus, the results have been interpreted based on the self-aggregation, hydrophobicity, charge densities of the co-ligand and the reactants with opposite charges.

Modification of Electrospun CeO2 Nanofibers with CuCrO2 Particles Applied to Hydrogen Harvest from Steam Reforming of Methanol.

Hydrogen is the alternative renewable energy source for addressing the energy crisis, global warming, and climate change. Hydrogen is mostly obtained in the industrial process by steam reforming of natural gas. In the present work, CuCrO2 particles were attached to the surfaces of electrospun CeO2 nanofibers to form CeO2-CuCrO2 nanofibers. However, the CuCrO2 particles did not readily adhere to the surfaces of the CeO2 nanofibers, so a trace amount of SiO2 was added to the surfaces to make them hydrophilic. After the SiO2 modification, the CeO2 nanofibers were immersed in Cu-Cr-O precursor and annealed in a vacuum atmosphere to form CeO2-CuCrO2 nanofibers. The CuCrO2, CeO2, and CeO2-CuCrO2 nanofibers were examined by X-ray diffraction analysis, transmission electron microscopy, field emission scanning electron microscopy, scanning transmission electron microscope, thermogravimetric analysis, and Brunauer-Emmett-Teller studies (BET). The BET surface area of the CeO2-CuCrO2 nanofibers was 15.06 m2/g. The CeO2-CuCrO2 nanofibers exhibited hydrogen generation rates of up to 1335.16 mL min-1 g-cat-1 at 773 K. Furthermore, the CeO2-CuCrO2 nanofibers produced more hydrogen at lower temperatures. The hydrogen generation performance of these CeO2-CuCrO2 nanofibers could be of great importance in industry and have an economic impact.

Fabrication of CuYO2 Nanofibers by Electrospinning and Applied to Hydrogen Harvest.

Hydrogen can be employed as an alternative renewable energy source in response to climate change, global warming, and the energy problem. Methanol gas steam reforming (SRM) is the major method used in industry to produce hydrogen. In the SRM process, the catalyst nature offers benefits such as low cost, simplicity, and quickness. In this work, delafossite copper yttrium oxide (CuYO2) nanofibers were successfully prepared by electrospinning. The prepared CuYO2 nanofibers have different physical and chemical properties including thermoelectric behavior. The electrospinning method was used to produce as-spun fibers and annealed in an air atmosphere to form Cu2Y2O5 fibers; then, Cu2Y2O5 fibers were annealed in a nitrogen atmosphere to form CuYO2 nanofibers. X-ray diffraction studies and thermogravimetric and transmission electron microscope analysis confirmed the formation of CuYO2 nanofibers. The CuYO2 nanofibers were applied to methanol steam reforming for hydrogen production to confirm their catalytic ability. The CuYO2 nanofibers exhibited high catalytic activity and the best hydrogen production rate of 1967.89 mL min-1 g-cat-1 at 500 °C. The highly specific surface area of CuYO2 nanofibers used in steam reforming reactions could have significant economic and industrial implications. The performance of these CuYO2 nanofibers in hydrogen generation could be very important in industries with a global economic impact. Furthermore, the H2 production performance increases at higher reaction temperatures.

ZnO-ZnCr2O4 composite prepared by a glycine nitrate process method and applied for hydrogen production by steam reforming of methanol.

To address climate change, the energy crisis, and global warming, hydrogen (H2) can be used as a potential energy carrier because it is clean, non-toxic and efficient. Today, the mainstream industrial method of H2 generation is steam reforming of methanol (SRM). In this process, a zinc-based commercial catalyst is usually used. In this work, a ZnO-ZnCr2O4 catalyst was successfully synthesised by the glycine nitrate process (GNP) and developed for use in H2 production by SRM. The specific surface area, porous structure and reaction sites of the zinc-based catalyst were effectively increased by the preparation method. The as-combusted ZnO-ZnCr2O4 composite catalyst had a highly porous structure due to the gas released during the GNP reaction process. Moreover, according to the ZnO distribution and different G/N ratios, the specific surface area (S BET) of the as-combusted ZnO-ZnCr2O4 catalyst varied from 29 m2 g-1 to 46 m2 g-1. The ZnO-ZnCr2O4 composite catalyst (G/N 1.7) exhibited the highest hydrogen production, 4814 ml STP min-1 g-cat-1, at a reaction temperature of 450 °C without activation treatment. After activation, the ZnO-ZnCr2O4 composite catalyst achieved hydrogen production of 6299 ml STP min-1 g-cat-1 at a reaction temperature of 500 °C. The hydrogen production performance of the ZnO-ZnCr2O4 composite powder was improved by the uniform addition of ZnO to ZnCr2O4. Based on the performance, this ZnO-ZnCr2O4 composite catalyst has great potential to have industrial and economic impact due to its high efficiency in hydrogen production.

Investigation of electrocatalytic and photocatalytic ability of Cu/Ni/TiO2/MWCNTs Nanocomposites for detection and degradation of antibiotic drug Furaltadone.

In this manuscript, "Get two mangoes with one stone" strategy was used to study the electrochemical detection and photocatalytic mineralization of furaltadone (FLT) drug using Cu/Ni/TiO2/MWCNTs nanocomposites for the first time. The bi-functional nanocomposites were synthesized through a hydrothermal synthesis technique. The successfully synthesized nanocomposites were analyzed by various analytical techniques. The Cu/Ni/TiO2/MWCNTs nanocomposites decorated screen-printed carbon electrode (SPCE) exhibit a good electrocatalytic ability towards detection of FLT. Moreover, the electrocatalytic detection of FLT based on the nanocomposites decorated SPCE have high stability, lower detection limit, and excellent sensitivity of 0.0949 µM and 1.9288 µA µM-1 cm-2, respectively. In addition, the nanocomposites decorated SPCE electrodes performed in real samples, such as river water and tap water, the satisfactory results were observed. As UV-Visible spectroscopy revealed that the Cu/Ni/TiO2/MWCNTs nanocomposites had an excellent photocatalytic ability for degradation of FLT drug. The higher degradation efficiency of 75% was achieved within 45 min under irradiation of visible light. In addition, after the degradation process various intermediates are produced which is confirmed by GC-MS analysis. The excellent photocatalytic ability was improved to the dopant ions and restrictions of electron-hole pair.

Environmental Remediation of Toxic Organic Pollutants Using Visible-Light-Activated Cu/La/CeO2/GO Nanocomposites.

Environmental pollution is a major threat that increases day by day due to various activities. A wide variety of organic pollutants enter the environment due to petrochemical activities. Organic contamination can be unsafe, oncogenic, and lethal. Due to environmental issues worldwide, scientists and research communities are focusing their research efforts on this area. For the removal of toxic organic pollutants from the environment, photocatalysis-assisted degradation processes have gained more attention than other advanced oxidation processes (AOPs). In this manuscript, we report a novel photocatalysis of copper and lanthanum incorporating cerium oxide (CeO2) loaded on graphene oxide (Cu/La/CeO2/GO) nanocomposites successfully synthesized by hydrothermal techniques. XRD results showed the presence of dopant ions and a crystalline structure. FESEM images showed that the surface morphology of the synthesized nanocomposites formed a rod-like structure. The highlight of this study is the in-situ synthesis of the novel Cu/La/CeO2/GO nanocomposites, which manifest higher photodegradation of harmful organic dyes (Rhodamine B (RhB), Sunset Yellow (SY), and Cibacron Red (CR)). In Cu/La/CeO2/GO nanocomposites, the dopant materials restrict the rapid recombination of photoinduced electron-hole pairs and enhance the photocatalytic activity. The degradation percentages of RhB, SY, and CR dye solution are 80%, 60%, and 95%, respectively. In summary, the synthesized nanocomposites degrade toxic organic dyes with the help of visible light and are suitable for future industrial applications.

Novel construction of carbon nanofiber/CuCrO2 composite for selective determination of 4-nitrophenol in environmental samples and for supercapacitor application.

A simple hydrothermal process has been used to prepare a carbon nanofiber/copper chromium dioxide (CNF/CuCrO2) composite for the selective detection of 4-nitrophenol (4-NP) and supercapacitor applications. The electrochemical sensor was developed with a glassy carbon electrode (GCE) modified with the CNF/CuCrO2 composite by the drop-casting method. The structural formation of the prepared materials was confirmed by infrared spectroscopy, electrochemical impedance spectroscopy, Raman spectroscopy, scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. To investigate the electrochemical efficiency of the electrode, various electroanalytical techniques, namely, differential pulse voltammetry (DPV), cyclic voltammetry (CV) and galvanostatic charge-discharge tests, were employed. The GCE/CNF/CuCrO2 modified electrode exhibited excellent electrocatalytic behavior for the detection of 4-NP under optimized conditions with a low detection limit (0.022 µM), long linear response range of 0.1-150 µM, and high sensitivity (20.02 µA µM-1 cm-2). The modified electrode was used for the detection of 4-NP in real samples with satisfactory results. In addition, the GCE/CNF/CuCrO2 electrode has advantages such as stability, reproducibility, repeatability, reliability, low cost, and practical application. The CNF/CuCrO2 composite coated Ni-foam electrodes also exhibited excellent supercapacitor efficiency, with a high specific capacitance of up to 159 F g-1 at a current density of 5 A g-1 and outstanding cycling stability. Hence, the CNF/CuCrO2 composite is a suitable material for 4-NP sensors and energy storage applications.

Hydrothermal synthesis of high surface area CuCrO2 for H2 production by methanol steam reforming.

Hydrogen (H2) is viewed as an alternative source of renewable energy in response to the worldwide energy crisis and climate change. In industry, hydrogen production is mainly achieved through steam reforming of fossil fuels. In this research, hydrothermally-synthesized delafossite CuCrO2 nanopowder were applied in methanol steam reforming. Reducing the size of the CuCrO2 nanopowder significantly improved the efficiency of hydrogen production. The prepared CuCrO2 nanopowder were characterized by X-ray diffraction, Brunauer-Emmett-Teller (BET) analysis, field emission scanning electron microscopy, and transmission electron microscopy. The calculated BET surface area of the hydrothermally synthesized CuCrO2 nanopowder was 148.44 m2 g-1. The CuCrO2 nanopowder displayed high catalytic activity, and the production rate was 2525 mL STP per min per g-cat at 400 °C and a flow rate of 30 sccm. The high specific area and steam reforming mechanism of the CuCrO2 nanopowder catalyst could have vital industrial and economic effects.

Activated Graphite Supported Tunable Au-Pd Bimetallic Nanoparticle Composite Electrode for Methanol Oxidation.

Methanol (CH3OH) is a favorable fuel for direct methanol fuel cells (DMFCs) in compact devices. This work, we present a facile and simple approach to make divergent molar ratios uniform gold (Au) and palladium (Pd) nanoparticles (NPs) decoration on an activated graphite (AGR) electrode. The binary combination of these AGR/Au-Pd catalysts composition is controlled by modifying the molar ratio of the Au and Pd precursors. The AGR/Au-Pd composite was characterized by suitable microscopy and spectroscopy characterization technique. Electrochemical studies of the prepared material were also conducted by chronoamperometry (CA) and cyclic voltammetry (CV) methods. The AGR/Au-Pd composite nanoparticles were successfully prepared and decorated on an activated screen-printed carbon electrode (ASPCE) surface. The ASPCE/AGR/Au-Pd electrode has great potential and stability for DMFCs. The prepared modified electrode was compared by a Pt/C electrode, and its efficiency was better than those of previously reported modified electrodes. Additionally, the electrocatalytic reaction of methanol oxidation is a surface controlled process on the electrode surface.

Reduced Graphene Oxide/Multiwalled Carbon Nanotube Composite Decorated with Fe3O4 Magnetic Nanoparticles for Electrochemical Determination of Hydrazine in Environmental Water.

In the present work, a reduced graphene oxide and multiwalled carbon nanotube (RGO/MWCNTFe3O4) composite decorated with Fe3O4 magnetic nanoparticles was prepared as an electrochemical sensor. The surface morphology of the prepared composite was identified by scanning electron microscopy and X-ray diffraction. The electrochemical properties of the GCE/RGO/MWCNT-Fe3O4 electrode were investigated by electrochemical impedance spectroscopy, cyclic voltammetry and amperometry. The GCE/RGO/MWCNT-Fe3O4 electrode exhibited higher electrocatalytic performance towards the oxidation of hydrazine. In the optimal conditions, the GCE/RGO/MWCNT-Fe3O4 electrode showed a wide linear range (0.15-220 µM), low limit of detection (LOD) (0.75 µM), and high sensitivity (2.868 µA µM-1 cm-2). The prepared GCE/RGO/MWCNT-Fe3O4 electrode also had excellent repeatability, selectivity, and reproducibility. The practical application of the electrode was confirmed with various spiked water samples and demonstrated acceptable recovery.

Preparation of CuCrO2 Hollow Nanotubes from an Electrospun Al2O3 Template.

A hollow nanostructure is attractive and important in different fields of applications, for instance, solar cells, sensors, supercapacitors, electronics, and biomedical, due to their unique structure, large available interior space, low bulk density, and stable physicochemical properties. Hence, the need to prepare hollow nanotubes is more important. In this present study, we have prepared CuCrO2 hollow nanotubes by simple approach. The CuCrO2 hollow nanotubes were prepared by applying electrospun Al2O3 fibers as a template for the first time. Copper chromium ions were dip-coated on the surface of electrospun-derived Al2O3 fibers and annealed at 600 °C in vacuum to form Al2O3-CuCrO2 core-shell nanofibers. The CuCrO2 hollow nanotubes were obtained by removing Al2O3 cores by sulfuric acid wet etching while preserving the rest of original structures. The structures of the CuCrO2-coated Al2O3 core-shell nanofibers and CuCrO2 hollow nanotubes were identified side-by-side by X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. The CuCrO2 hollow nanotubes may find applications in electrochemistry, catalysis, and biomedical application. This hollow nanotube preparation method could be extended to the preparation of other hollow nanotubes, fibers, and spheres.

A cerium vanadate interconnected with a carbon nanofiber heterostructure for electrochemical determination of the prostate cancer drug nilutamide.

Cerium vanadate resembling the shape of a hedgehog were interconnected with carbon nanofibers to give a heterostructure (referred to as CeV/CNF) that exhibits efficient catalytic activity for the electrochemical detection of the drug nilutamide (NLT). The heterostructure material and its modification were characterized by XRD, Raman spectra, XPS, FESEM, TEM, SAED, and EDX. A glassy carbon electrode was modified with the CeV/CNF nanocomposite. Best operated at -0.52 V (vs. Ag/AgCl), it exhibits a very low detection limit (2.0 nM), wide linear range (0.01-540 µM), high sensitivity (1.36 µA µM-1 cm-2) and rapid response towards NLT. It was applied to the determination of NLT in spiked human urine. Graphical abstractSchematic presentation of cerium vanadate interconnected with carbon nanofiber heterostructure for electrochemical determination of prostate cancer drug nilutamide in biological samples.