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Presently, researchers are focusing towards the fabrication and use of metal-doped nanomaterials, which can offer outstanding capacitive performance. Hence, we are motivated to report Mo-doped Co3O4 porous nanostructures with different molybdenum contents prepared via a facile sol–gel strategy. The tuned crystalline, morphological, and elemental properties were confirmed with XRD and SEM equipped with EDX techniques. These nanomaterials were consisted on nanostructures with average size in the range of 40–60 nm. To examine the improved capacitive characteristics, electrochemical tests like CV, GCD, and EIS were conducted in a 3 M KOH electrolyte solution. The as-synthesized 5 at.% Mo-doped Co3O4 nanomaterial achieved an outstanding specific capacitance, i.e., 858.09 F/g, tested at a scan rate of 5 mV/s and an outstanding rate capability, i.e., 83.33% at 10 A/g higher scan rate during GCD tests at different scan rates ranging from 1 to 10 A/g. Furthermore, these nanostructures also exhibited high capacitance retention, i.e., 82.74% after 3000 CV cycles performed at scan rate of 5 mV/s. The superior supercapacitive performance of this material is credited to the development of nanostructures with high surface-to-volume ratio, enhanced specific capacitance, and good conductivities, achieved by appropriate molybdenum content. Hence, this material holds ideal promise for supercapacitor application. [ABSTRACT FROM AUTHOR]

Summary: Highly efficient and stable fullerene‐WO3 composites were prepared through hydrothermal method for photocatalytic applications and evolution of green hydrogen energy under visible light irradiation. The prepared nanostructures were characterized through scanning electron microscopy, X‐ray diffractometer, energy‐dispersive X‐ray, Brunauer‐Emmett‐Teller, ultraviolet‐visible spectrometer, and photoluminescence spectroscopy to investigate morphological, structural, elemental composition, surface area, and optical properties of prepared samples. The presence of fullerene in WO3 could tune the morphology, crystallographic structure, and optical properties of the as‐prepared nanostructures. The highest photocatalytic activity was achieved at 4% fullerene contents; however, further increase in doping contents may lead to lower photocatalytic performance. The improved photocatalytic performance was attributed to 3 factors, namely, (1) higher surface area, (2) extended visible light region, and (3) inhibited recombination losses. [ABSTRACT FROM AUTHOR]

In this article, visible light driven graphene-WO 3 (WG) photocatalysts have been synthesized through facile hydrothermal process for H 2 evolution through water splitting under visible light illumination. For comparison, neodymium-WO 3 nanostructure was also prepared. The as-synthesized composites were characterized by XRD, SEM, BET, EDX, XPS, UV–vis absorption spectra and Photoluminescence (PL) emission spectroscopy. Experimental results showed that WG-7 composite (7% graphene content into WO 3 ) had excellent photocatalytic performance (rate of H 2 evolution 288/µmol h −1 g −1 ) towards hydrogen production when compared to pristine WO 3 . It was also confirmed by optical analysis that incorporation of graphene into WO 3 and Nd-WO 3 photocatalysts prevented the electron-hole recombination and boosts the reduction reactions for H 2 evolution. PL emission spectra confirmed the effective charge-separation in graphene incorporated WO 3 composite. It was demonstrated that photocatalytic activity for hydrogen production increases with increasing doping content of graphene upto 7 at%. However, further increase in incorporated content above optimal level has decreased the photocatalytic performance of the composite. The enhanced photocatalytic activity of WG composites could be attributed to extended visible light absorption, high surface area and efficient charge-separation due to synergistic effects between graphene and WO 3 . This study gives a new perspective on the fabrication of novel photocatalyst for environmental and energy applications. [ABSTRACT FROM AUTHOR]

Abstract: We here report highly pure and single crystalline grass-like gallium nitride (GaN) nanostructures obtained on silicon substrate via catalyst-assisted CVD route under NH3 atmosphere inside horizontal tube furnace (HTF) by pre-treating the precursors with aqueous NH3. The as-obtained GaN nanostructures were characterized by XRD, SEM, EDS, HRTEM and SAED. The field emission (FE) characteristics of grass-like GaN nanostructures exhibited a turn-on field of 7.82Vμm−1 and a threshold field of 8.96Vμm−1 which are quite reasonable for applications in electron emission devices, field emission displays and vacuum microelectronic devices. Room temperature photoluminescence (PL) measurements of grass-like GaN nanostructures exhibited a strong near-band-edge emission at 368.8nm (3.36eV) without any defects related emissions which shows its potential applications in optoelectronics. [Copyright &y& Elsevier]

The incorporation of 3d magnetic ions into intrinsic semiconductors is one of the sophisticated way to tune their opto-magnetic behavior but dire need is to determine the functional changes resulting from doped-ions. Here, dysprosium (Dy) ions have been doped into CdS nanostructures via co-precipitation technique and studied their influence in optical and magnetic properties. The PL of doped-nanostructures exhibited violet, blue (454.5 nm) and orange emissions, simultaneously. The violet emissions correspond to the band edge (BE) emission of CdS and blue emissions appeared due to the f-f transition from Dy4+ to Dy3+ and Dy3+. Burstein-Moss-Effect explains the increased band-gap observed in the doped samples. VSM studies show the formation of ferromagnetism in a diamagnetic CdS nanostructure due to the successful incorporation of Dy3+ ions into CdS which can play a significant role in tuning their optical and magnetic properties for potential applications in optical devices and spintronics. • First synthesis of dysprosium-doped CdS nanostructures via chemical coprecipitation method. • Dy3+ ions related emissions detected for the first time in wide bandgap semiconductors. • Inclusion of Dy3+ ions turn diamagnetic CdS into ferromagnetic material. • These materials show promise for optoelectronic and spintronic applications. [ABSTRACT FROM AUTHOR]

• CuS hierarchical micro structures were synthesized using solvothermal technique through mixed solvents. • Solvent play a crucial role in governing growth and determining the final morphology of the CuS architectures. • The prepared sample showed excellent efficiency towards photocatalysis applications. A variety of high-quality, shape and size consistent nanostructures of copper sulfide (CuS) in the form of hierarchical architectures composed of intersecting nano-sheets have been fabricated via mixed solvent route. Copper chloride and thiourea have been utilized as precursors for copper and sulfur sources for each experimentation in the presence of a variety of mixed solvents to obtain various morphologies of CuS. The prepared products have been characterized by X-ray powder diffraction (XRD) and all of the synthesized products have been investigated to be the phase pure single crystalline. Scanning Electron Microscopy (SEM) revealed the well-ordered and isolated particles. The Energy Dispersive Spectroscopy (EDS) spectrum further proved that the obtained products in all of the synthetic processes don't contain any kind of impurity. Ultraviolet– visible–near infrared (UV–vis–NIR) transmittance spectrophotometer has been utilized to ascertain the optical properties of the as prepared nanostructures. An extended U.V absorption in near-IR region, indicate the covellite phase of CuS. Most importantly, the synthesized nanostructures demonstrated an excellent photo-catalyst response in degrading highly concentrated rhodamine B (RhB) dye aqueous solutions under visible light irradiation along with an excellent reusability, suggesting a promising application in wastewater purification. The excellent photo-catalytic activity has been attributed to surface hierarchical structure with good absorbing and adsorbing properties, high visible light utilization and low electron hole recombination rate. [ABSTRACT FROM AUTHOR]

Cd x Zn 1-x Mg 0.25 Fe 1.75 O 4 (where x = 0.00, 0.25, 0.50, 0.75, 1.00) have been successfully produced by a facile hydrothermal technique for a thorough comparison of structural, optical, and photocatalytic properties (degradation of Rhodamine B -RhB dye under visible light irradiation). X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) confirmed the formation of cubic spinel structure for all of the samples. Fourier transform infrared (FTIR) spectroscopy verified the presence of metal-oxygen (M–O) bonding in the prepared samples with two frequency bands corresponding to phonon vibrational stretching in both the octahedral and tetrahedral lattice positions. UV–Visible Spectrophotometer and photoluminescence (PL) spectroscopy investigated the bandgap variation (2.7 eV-1.7 eV) and emission spectrum peaks appearing in the range of 405–471 nm region. The comparison in the photo-degradation of Rhodamine B (RhB) revealed the superior performance (98% degradation of RhB dye in 80 min having a K value of 0.04966 with excellent reusability) of Cd 0.50 Zn 0.50 Mg 0.25 Fe 1.75 O 4 sample having 50/50 dopant ratio of Cd and Zn in the parent Mg Ferrite, attributed to the lowest bandgap, longer lifetime of charge carriers, active octahedral lattice site, electron/hole pair recombination preventions, and the least value of ohmic impedance at higher frequency. [ABSTRACT FROM AUTHOR]

Abstract Mimicking the natural photosynthesis system, artificial photocatalysis facilitates effective utilization of solar energy for environmental sustainability and hydrogen energy production. In this work, the robust and efficient carbon fiber has been successfully incorporated into the interface between WO 3 nanodots and MoSe 2 needles using the facile hydrothermal and solvothermal method. The suitable interfacial contact of heterogeneous photocatalysts plays a significant role in the separation/transfer of interfacial photogenerated electron-hole pairs and hetero-junction. It seems an efficient approach for enhanced photocatalytic performance since the greater area of contact could improve the interfacial rate of charge transfer. The phase structure of prepared WO 3 nanodots changed from the monoclinic to hexagonal phase by the addition of co-catalyst. The experimental results exhibited that carbon fiber played a tri-functional role to boost up the photocatalytic activity over MoSe 2 nanostructures. It's not only act as operative co-catalyst but could also serve as the conductive electron bridges, rather than general cocatalyst, to accumulate electrons and encourage the hydrogen generation kinetics over the WO 3 photocatalysts. More interestingly, the WO 3 −1% MoSe 2 −1.5% carbon fiber and WO 3 −1%MoSe 2 nanocomposites demonstrated the excellent rates of hydrogen evolution 438.7 and 356.2 mmol/g.h, which were 7.6 and 6.17 times higher when compared to that of pure MoSe 2 , respectively. Under the visible light excitation, the atomically junction encourages fast electron transfer from nanofibers to MoSe 2 to suppress the rapid recombination kinetics within WO 3 nanodots and extend the lifetime of WO 3 charge carrier's, thereby releasing more photogenerated electrons with higher reducing power for hydrogen evolution. The current work can contribute with new perspectives and mechanistic insight for the design and development of heterogeneous photocatalysts WO 3 based nanostructures using the combination of MoSe 2 and trifunctional carbon nanofibers for environment and energy harvesting applications. [ABSTRACT FROM AUTHOR]

[Display omitted] The novel study of Cd-Zn co-doped Magnesium ferrites Cd x Zn 1-x Mg 0.25 Fe 1.75 O 4 (where x = 0, 0.25, 0.75, 0.50, and 1.00) has been made successfully by adopting a facile sol-gel extended hydrothermal pathway. Structural, optical, and magnetic behavior of the Cd-Zn co-doped Magnesium ferrites were systematically analyzed. From the X-ray Diffraction (XRD) patterns it was confirmed that the prepared samples have a cubic spinel structure. Scanning electron microscopic (SEM) study revealed the agglomerated and irregular shape of Cd-Zn co-doped Magnesium ferrites nanoparticles. Fourier transforms infrared (FTIR) spectroscopy has been studied for the confirmation of the presence of (M-O) bonding in the synthesized samples. Furthermore, the synthesized samples showed two frequency bands related to phonon vibrational stretching in both octahedral and tetrahedral lattice positions. The PL spectrum revealed the strong emission peaks in the ultraviolet to the visible region of all the synthesized samples. Raman spectroscopy showed the formation of four active modes due to the cubic spinel structure of all samples. Finally, the magnetic characteristics are calculated by using a vibrating sample magnetometer (VSM) showing ferrimagnetic and soft magnetic behavior of all the Magnesium ferrite samples. As the Cd and Zn co-doping in Mg ferrites was increased, the H c was decreased. The magnetic studies revealed that the maximum H c of 576 Oe and maximum saturation magnetization (M s) appeared for the sample Cd 0.50 Zn 0.50 Mg 0.25 Fe 1.75 O 4 , carrying Cd/Zn in 50/50 ratio. It is envisaged that the novel preparation of Cd-Zn co-doped Magnesium ferrite would be suitable for several applications, for example, magnetic recording devices, actuators, high-density data storage devices sensors, and biomedical equipments. [ABSTRACT FROM AUTHOR]

Abstract: Large scale metallic cadmium (Cd) nanotubes with high purity have been obtained on glass substrate by catalyst-free thermal decomposition of cadmium oxide (CdO) powder at 1200 °C for 120 min using argon (Ar) gas as carrier agent inside an alumina tube mounted in horizontal tube furnace. The structural, compositional and morphological characterizations of cadmium nanotubes (CdNTs) were performed by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED). The CdNTs were observed to be single crystalline with 60–70 nm diameter and tens of micrometre length. Based on vapour–solid (VS) and rolling layer mechanisms, growth process has been proposed for the formation of CdNTs. Room temperature photoluminescence (PL) spectrum for CdNTs recorded under xenon light wavelength of 325 nm exhibited a very prominent emission band at 383 nm which may be ascribed to either surface oxidation effects or radiative recombination of electrons in the s, p conduction band near the Fermi surface and the holes in the d bands generated by xenon light excitation. This shows the promise of CdNTs for applications in UV-light emitting devices. [Copyright &y& Elsevier]

Abstract: We report here the simultaneous growth of ZnSe cactus-like structures with nanorods emerging from their surface and selenium microflowers using Zn and Se powders as precursors. ZnSe cactuses were obtained by solid state chemical reaction whereas selenium microflowers were obtained by thermal evaporation and condensation process. ZnSe cactuses consist of spheres with diameter range 2–3μm having nanorods with diameter in the range 60–90nm on the exterior surface. The mixture of zinc and selenium powders with few drops of aqueous ammonia loaded in semicircular long alumina boat was heated inside horizontal tube furnace at 500°C for 180min under ammonia atmosphere. The structural, compositional and morphological characterizations have been performed by means of Scanning Electron Microscope (SEM), the Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD). Room temperature photoluminescence (PL) measurement of as-synthesized products show two intensive peaks centered at 404nm and 427nm (2.85eV), which are attributed to the band edge emission of ZnSe. These two strong emission bands are blue shifted; this blue shift is because of quantum size confinement effect of nanostructures. A very weak peak centered at 464nm (2.67eV) is also observed in our sample which is exactly equivalent to the peak associated with the bulk ZnSe, and is attributed to near band edge emission (NBE) for the ZnSe nanostructures. [Copyright &y& Elsevier]

Abstract: We report here the evolution of zinc based high purity phases with novel morphologies such as Zn3N2 hollow structures, ZnO nanowires and nanopowders, as well as metallic Zn layered hexagonal microparticles at progressively increased reaction temperature of 600°C, 700°C, 800°C under NH3 gas atmosphere using Zn powder precursor and keeping all other experimental parameters unchanged. Growth mechanism for Zn3N2 obtained by nitridation, ZnO by oxidation and Zn microparticles via thermal evaporation & condensation process are discussed briefly. The as-synthesized products were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). Photoluminescence (PL) studies have revealed very interesting and infrequently observed emission bands at 378 and 661nm for Zn3N2, 359 and 396nm for ZnO as well as 389nm for Zn polyhedral microparticles. [Copyright &y& Elsevier]