Absorption spectra of antimony pentachloride-aromatic hydrocarbon systems

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Pure brookite titania crystals with large surface area deposited by Plasma Enhanced Chemical Vapour Deposition technique

Pure brookite phase titania crystals with large surface area have been synthesized at room temperature by the Plasma Enhanced Chemical Vapour Deposition technique, using titanium tetra-isopropoxide vapour, argon and oxygen mixtures, deposited on silicon (100) substrates under an applied substrate d.c. bias voltage of −250 V. The X-ray diffraction analysis for the as-deposited titania has confirmed the crystallinity and phase as brookite titania. Scanning Electron Microscope micrographs show the morphology of the brookite titania crystals with largest lateral dimensions of about 500×1200 nm, i.e. relatively large surface area crystals. There are no reports on the preparation of brookite titania crystals with such large surface areas

A type-II semiconductor (ZnO/CuS heterostructure) for visible light photocatalysis

Type-II semiconductors with p–n heterojunctions have been fabricated by decorating CuS nanostructures on the surface of ZnO nanotubes with the help of a wet-chemical method at low temperature. We are reporting the enhanced visible light photocatalytic efficiency of ZnO/CuS heterostructures. CuO nanostructures were synthesized on the surface of ZnO nanotubes and then the CuO nanostructures were converted to CuS at 80 °C to generate the ZnO/CuS heterostructures. These ZnO/CuS heterostructures efficiently decompose methylene blue upon irradiation of visible light at room temperature. A study of the mechanism suggests that the enhanced photocatalytic activity is due to the formation of ZnO/CuS junctions, which leads to the efficient separation of photoinduced carriers

Nanosheets of NiCo₂O₄/NiO as Efficient and Stable Electrocatalyst for Oxygen Evolution Reaction

Development of a stable catalyst that can efficiently function for longer time for energy conversion process in water splitting is a challenging work. Here, NiCo₂O₄/NiO nanosheets are successfully synthesized following a simple wet-chemical route, followed by the combustion technique. Finally, the synthesized catalyst NiCo₂O₄/NiO can function as an efficient catalyst for oxygen evolution reaction. Nanosheets with interconnections are very useful for better electron transportation because the pores in between the sheets are useful for the diffusion of electrolyte in electrocatalysis. In oxygen evolution reaction, these sheets can generate current densities of 10 and 20 mA/cm², respectively, upon application of 1.59 and 1.62 V potential versus reversible hydrogen electrode (RHE) under alkaline condition. In contrast, bare NiCo₂O₄ nanowire bundles can generate a current density of 10 mA/cm² upon application of 1.66 V versus RHE. The presence of NiO in NiCo₂O₄/NiO nanosheets helps to increase the conductivity, which further increases the electrocatalytic activity of NiCo₂O₄/NiO nanosheets

Preparation of large surface area rutile titania crystals at room temperature by PECVD with applied d.c. bias

Rutile titania crystals with large surface area have been synthesized by PECVD at room temperature using titanium tetraisopropoxide [TTIP] vapour and argon and oxygen mixtures on silicon (100) substrates, under an applied substrate bias of -350 V d.c. The XRD pattern confirms the crystallinity and phase of the crystals as rutile titania. SEM micrographs show the rutile titania crystals with largest lateral dimensions of about 400 x 600 nm, i.e. with relatively large surface areas. There are no reports on the preparation of rutile titania crystals with large surface areas

Nickel cobaltite nanostructures with enhanced supercapacitance activity

Herein, we report a strategy for controlled synthesis of functional nanomaterials desired for energy conversion and power storage applications. NiCo2O4 nanostructures with square sheets, hexagonal sheets, and spherical form have been synthesized using a solvothermal route by tuning of reaction conditions as well as selection of hydrolyzing agents. The synthesized nanostructures exhibited significant shape dependent electrochemical behavior with improved supercapacitance as well as good electrocatalytic properties toward oxygen evolution reaction. Among all the three morphologies, the square sheets, assembled from nanoparticles ∼5 nm diameter, exhibited higher specific capacitance with good stability. Due to high surface area (∼100 m2/g) and the mesoporous nature of the square sheets, NiCo2O4 reveals better pseudocapacitance

Optical thin films of silica and titania deposited by plasma polymerisation process: System design and fabrication

Plasma polymerization provides a very versatile and cost-effective technique for the deposition of a wide variety of dielectric films, in particular optical thin films of silica (silicon dioxide) and titania (titanium dioxide) that are widely used as low and high index films in optical multilayer coatings for a variety of applications. The deposition of these films is often carried out using toxic and corrosive precursors–silane gas for silica and titanium tetrachloride liquid for titania – that are expensive and difficult to handle. The use of non-toxic organic liquid precursors, that are cheaper and safer and easier to handle, has been reported for the deposition of these films. In order to develop indigenous expertise in such deposition processes, a plasma polymerization deposition system that uses non-toxic and safe organic liquid precursors for the deposition of optical quality silica and titania films has been designed and fabricated in-house and successfully made operational. The problems that arise in this deposition process, the methods adopted to overcome them, the precautions that must be taken, have been studied in detail. Optical quality silica and titania films with satisfactory refractive indices and extinction coefficients have been deposited using this home-made deposition system

Nickel Cobaltite Nanostructures with Enhanced Supercapacitance Activity

Herein, we report a strategy for controlled synthesis of functional nanomaterials desired for energy conversion and power storage applications. NiCo₂O₄ nanostructures with square sheets, hexagonal sheets, and spherical form have been synthesized using a solvothermal route by tuning of reaction conditions as well as selection of hydrolyzing agents. The synthesized nanostructures exhibited significant shape dependent electrochemical behavior with improved supercapacitance as well as good electrocatalytic properties toward oxygen evolution reaction. Among all the three morphologies, the square sheets, assembled from nanoparticles ∼5 nm diameter, exhibited higher specific capacitance with good stability. Due to high surface area (∼100 m²/g) and the mesoporous nature of the square sheets, NiCo₂O₄ reveals better pseudocapacitance