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The demand of composite materials with enhanced electrochemical performance for supercapacitors is emerging. With the aim to improve the electrochemical performance, g-C 3 N 4 , TiS 2 and TiS 2 /g-C 3 N 4 composite have been synthesized by a facile hydrothermal approach. The structure and surface morphology of the synthesized materials were analyzed by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-rays spectroscopy (EDS). The electrochemical performance of TiS 2 and TiS 2 /g-C 3 N 4 composites were studies by using three electrode system in 2 M KOH electrolyte. The TiS 2 /g-C 3 N 4 micro-composite showed the higher specific capacitance (546 F/g) as compared to TiS 2 (292 F/g) and g-C 3 N 4 (200–300 F/g) due to smaller size, additional active sites and strong synergic effect. More than 87% of the capacitance was retained after 2500 cycles, demonstrating the splendid cyclic stability of the composite. The improved specific capacitance and long cyclic stability of TiS 2 /g-C 3 N 4 micro-composites shows that this composite material is promising for supercapacitor electrodes. [ABSTRACT FROM AUTHOR]

A systematic approach has been introduced to synthesize Cd–Zn co-doped NiO nanostructures with different ratios such as Cd 0.07 Zn 0.03 NiO, Cd 0.05 Zn 0.05 NiO, Cd 0.03 Zn 0.07 NiO and Cd 0.01 Zn 0.09 NiO for supercapacitor applications. The XRD studies has confirmed the phase purity with average crystallite size of 40 nm. The SEM characterization has shown that the morphology of nanostructures was tuned from particles to nano-rods structure with increasing the at. % concentration of Zn doping. Optical properties revealed that band gap and recombination rate have strong co-relation with specific capacitance. The CV results have confirmed the pseudocapacitive nature of the as prepared nanostructures and maximum specific capacitance (1485.19 Fg-1) was measured for Cd 0.03 Zn 0.07 NiO which is superior than numerous reported values of NiO. The GCD results of Cd 0.03 Zn 0.07 NiO performed at 1 A/g scan rate, exhibited excellent charging-discharging ability with high cyclic retention of 82.8%. High capacitance and superior stability of Cd 0.03 Zn 0.07 NiO material indicate it as a potential candidate for supercapacitor applications. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation of organic dyes in wastewater using visible light illumination is a green technology which requires efficient visible-light driven active catalytic material. For this, we have reported a novel visible light active Eu/WO 3 system with variation in europium contents (0, 2%, 4% and 6% Eu), which demonstrated enhanced photocatalytic activity for the degradation of various organic dyes including methylene blue (MB), methyl orange ((MO) and rhodamine B (RhB). Scanning electron microscopy (SEM), X-ray diffractometer (XRD), energy dispersive X-ray (EDX), UV–visible spectroscopy and photoluminescence (PL) spectroscopy were used for the characterization of nanostructures. The results showed that Eu has effective role in modifying the structural, morphological and optical properties of WO 3 photocatalyst. Moreover, the photocatalytic performance of WO 3 was improved due to incorporation of Eu. From results, it was seen that photocatalytic activity increases with increasing Eu concentration upto 4%, however, further increase in Eu concentration (6%) has decreased the performance under these condition for all dyes. The enhanced photocatalytic efficiency could be attributed to suppressed recombination of charge carriers and enhanced visible light absorption and increased BET surface area due to Eu doping into WO 3 photocatalyst. The as-synthesized nanostructures will be considered as a promising photocatalytic materials for the future research in this field. [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]

We are reporting here a novel antimony doped cobalt oxide based electrode material for supercapacitor application to overcome the current scenario of energy crises by offering excellent capacitive abilities. A facile hydrothermal route was employed to produce this antimony doped cobalt oxide material by varying content value of antimony in the range of 2–6 at. %. The X-ray diffraction results have successfully explored the cubic crystal structure along with phase composition of these as obtained Sb doped Co 3 O 4 materials. The development of sub-micron sized structures-based material was explored by obtaining scanning electron microscopic images. The energy dispersive X-ray spectroscopy results have shown the highly pure nature of as obtained material. Cyclic voltammogram results have exhibited that among the SbCo-0, SbCo-2, SbCo-4 and SbCo-6 materials, SbCo-4 has exhibited higher specific capacitance value i.e 894.15 F/g than remaining, which was obtained by scanning the material at the scan rate of 5 mV/s. More significantly, Galvanostatic charge-discharge profiles obtained at different scan rates ranging from 1 to 10 A/g, for SbCo-4 material has shown even good capacitance retention i.e 75.70% at higher sweep rate, equal to 10 A/g. On the basis of electrochemical impedance spectroscopic analysis, it is concluded that this material has also shown excellent conductive properties. Furthermore, after performing 3000 galvanostatic charge-discharge cycles, it is concluded that this material can possessed an excellent cycling stability equal to 82.02%. All these excellent capacitive properties shown by this material have suggested that it can be proved as a potential applicant in the field of energy storage devices. [ABSTRACT FROM AUTHOR]

Zinc and cadmium based cobalt ferrites Zn x Cd 0.375-x Co 0.625 Fe 2 O 4 (where x = 0, 0.075, 0.125, 0.25) were successfully synthesized by a facile co-precipitation technique. Structural, optical and magnetic characteristics of the doped ferrites were systematically analyzed. X-ray Diffraction (XRD) pattern confirmed the formation of cubic spinel structure in all samples. Scanning electron microscopic analysis of surface morphology revealed cubic and spherical shaped ferrite particles. Fourier transform infrared (FTIR) spectroscopy confirmed the existence of metal oxygen (M − O) bonding in the prepared samples. Moreover, the prepared samples exhibited two frequency bands corresponding to phonon vibrational stretching in both octahedral and tetrahedral lattice positions. The optical properties were investigated in detail through photoluminescence (PL) spectroscopy and Raman spectroscopy. The PL spectrum confirmed the strong emission peaks in the ultraviolet to visible region of all the samples. Further, four active Raman modes, associated with cubic spinel structure are identified in all prepared samples. Finally, the magnetic characteristics are evaluated by using vibrating sample magnetometer (VSM) revealing ferrimagnetic and soft magnetic behavior of the samples. As the Zn and Cd co-doping in Co was increased, the H c was decreased. The magnetic studies show the maximum H c of 576 Oe for Cd doped cobalt ferrite, and maximum saturation magnetization (M s) for Zn–Cd doped cobalt ferrite. It is envisaged that the newly prepared Zn–Cd co-doped cobalt ferrite would be appropriate for a number of important applications, for example, magnetic recording devices, sensors, actuators, high-density data storage devices, and biomedical equipments. [ABSTRACT FROM AUTHOR]

Abstract In this work, We have successfully grown the crystalline Tin Oxide (SnO 2) micro-sheets by hydrothermal technique without using any catalyst. We also able to controlled the thickness of grown sheets by modulating the growth temperature and have reported the thickest micro-sheets (5 µm thick) for the first time. X-ray diffraction (XRD) studies confirm the tetragonal crystalline structure of grown SnO 2 and particle size was found to be increased from 2 to 15 nm as the synthesis temperature increased from 50 to 250 °C. SEM images have shown the micro-sheets like morphology of synthesized samples and the thickness of sheets increased from 1.4 to 5.1 ± 0.01 µm as the growth temperature increased from 150 to 250 °C respectively. Raman spectroscopy measurements showed a dominant peak at 639 cm−1 which is related to A 1g mode of SnO 2. The intensity of A 1g mode increased with growth temperature supporting the XRD results that the crystal structure of grown SnO 2 sheets improved with increasing growth temperature. Furthermore, the degree of crystanality, calculated from Raman data, increased to 68% at growth temperature 250 °C. The analysis of UV–Visible data demonstrated that increasing temperature from 150 ℃ to 250 ℃ causes the shift in the optical absorption edge from 280 to 290 nm respectively. [ABSTRACT FROM AUTHOR]

Highly efficient Eu-TiO 2 /graphene composites were synthesized by a two-step method such as sol-gel and hydrothermal process. The synthesized photocatalysts were characterized by XRD, TEM, XPS, UV–vis diffuse reflectance spectroscopy and photoluminescence (PL) spectroscopy. The results confirmed that anatase Eu-TiO 2 nanoparticles with average 10 nm sizes were successfully deposited on two-dimensional graphene sheets. The UV–visible spectroscopy showed a red shift in the absorption edge of TiO 2 due to Eu doping and graphene incorporation. Moreover, effective charge separation in Eu-TiO 2 /graphene composites was confirmed by PL emission spectroscopy compared to TiO 2 /graphene, Eu-TiO 2 and pure TiO 2 . The photocatalytic activity for H 2 evolution over prepared composites was studied under visible light irradiation (λ ≥ 400 nm). The results demonstrate that photocatalytic performance of the photocatalysts for hydrogen production increases with increasing doping concentration of Eu upto 2 at%. However, further increase in doping content above this optimum level has decreased the performance of photocatalyst. The enhanced photocatalytic performance for H 2 evolution is attributed to extended visible light absorption, suppressed recombination of electron-hole pairs due to synergistic effects of Eu and graphene. [ABSTRACT FROM AUTHOR]

Photocatalytic reduction of carbon dioxide (CO 2 ) into valuable hydrocarbon such as methane (CH 4 ) using water as reducing agent is a good strategy for environment and energy applications. In this study, a facile and simple sol-gel method was employed for the synthesis of metal (Cu and Ag) loaded nanosized N/TiO 2 photocatalyst. The prepared photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, BET Surface area analyzer, X-ray photoelectron spectroscopy and UV–vis diffuses reflectance spectroscopy. The photocatalytic conversion of CO 2 into methane was carried out under visible light irradiation (λ≥420 nm) by prepared photocatalysts in order to evaluate the photocatalytic efficiency. The results demonstrate that Ag loaded N/TiO 2 showed enhanced photocatalytic performance for methane production from CO 2 compared to other Cu–N/TiO 2 , N/TiO 2 and TiO 2 photocatalysts. The improvement in the photocatalytic activity could be attributed to high specific surface area, extended visible light absorption and suppressed recombination of electron – hole pair due to synergistic effects of silver and nitrogen in the Ag–N/TiO 2 photocatalyst. This study demonstrates that Ag–N/TiO 2 is a promising photocatalytic material for photocatalytic reduction of CO 2 into hydrocarbons under visible light irradiation. [ABSTRACT FROM AUTHOR]