In addition, TEA capped CuO nanocrystals were sharp, narrow and symmetric located at about 495 nm and 420 nm respectively. A dominant sharp emission peaks at 492 nm and 495 nm of the uncapped and TEA capped CuO nanocrystals were observed in violet to blue region supports the blue-shift behavior of the peak position, in comparison with bulk CuO. This observed blue-shift behavior is attributed to the enhanced quantum confinement effect due to decrease in the dimensions of the nanostructures. The uncapped and TEA capped CuO nanocrystals luminescence blue bands at 491 and 495 nm are caused by transition vacancy of oxygen and interstitial oxygen. However, the uncapped and TEA capped CuO nanocrystals photoluminescence
Conversion of neodymium oxide into nitrate by adding 2N nitric acid in a water bath is used as dopant precursor. This freshly prepared aqueous solution was added in lead nitrate solution with constant stirring until pale violet color turbid free solution is reached. The precipitation process was carried by drop wise addition of selenium dioxide into the lead nitrate solution under vigorous stirring, followed by addition of hydrazine hydrate to fix the pH and allowed to
0.1M of Zinc acetate dehydrate [Zn(CH3COO)2.2H2O] was dissolved in 40ml absolute ethanol under stirring at room temperature and 0.2M of sodium hydroxide (NaOH) was also dissolved in 10ml water under stirring at room temperature and then mixed in the Zn(CH3COO)2.2H2O solution. Then 0.004M PVP(poly vinyle pyrrolidone) was put into the reaction mixture. The resulting solution was stirred for several minutes. The solution was then transferred to polypropylene vessel, then sealed and heated in temperature-controlled autoclave at 800C for 24 hour. After cooling to room temperature, the white powder was precipitated and then washed with absolute ethanol several times to dissolve other impurities.
For the preparation of the catalyst, tetraethylorthosilicate (TEOS, Merck; purity> 99.9%) was dissolved in anhydrous ethyl alcohol (CH3CH2OH, Merck; purity>99.9%) under stirring for homogenization within 15 min at room temperature. After that, 3-aminopropyl(trimethoxy)silane (APS) was added to the ethanolic solution and mixed for >15 min. Then, Salicylaldehyde was added to the solution of TEOS and APS. The molar ratio of TEOS/APS/ Salicylaldehyde was 5:1:1. Then, Fe(NO3)3·9H2O (0.5mol) was added to above solution and was kept at 80 °C for 12h under reflux.
The peak at 1816 cm−1could is assigned to carbonyl stretching vibrations of carboxylic acids. The band found at 1679 cm−1could be assigned to characteristic asymmetrical stretch of carboxylate group. The symmetrical stretch of carboxylate group can be attributed to the bands present at 1491 and 1354 cm−1. The peaks at 1105 and 789 cm−1were due to the C–O stretching vibrations of polyols, ether and alcoholic
Figure 1(c) reveals that when Cr(NO3)3 concentration increased from 0.2 to 1.2 M, the nanocellulose crystallinity progressively increased from 62.5 to 83.9% while maintaining reaction duration for 1.5 h, a solid-liquid ratio of 1:30 at 80 °C. At the same time, the product yield decreased almost linearly with increasing concentration of metal salt. This implied that the successive degradation of amorphous allomorphs after the catalytic hydrolysis process and this induces the exposure of high crystallite segment in the nanocellulose which led to increasing of crystallinity. However, it is worth mentioning that the increasing tendency of crystallinity index became slower when the metal salt concentration was higher than 0.8 M. Therefore, for better economic competence, 0.8 M of metal salt catalyst was selected as an optimum concentration for
In a typical procedure, equimolar zinc nitrate hexahydrate [Zn(NO3)2, 6H2O] and hexamine (HMT) [(CH2)6N4] were dissolved in 80 ml D.I. (deionised) water to form a 0.04 M solution. Thereafter the solution was kept in a Pyrex bottle and heated in a regular laboratory oven at 110°C for 6 h. Finally the bottle was naturally cooled down and the product was collected by filtering and washing with copious amount of D. I. water. For the synthesis of ZnO-silica hybrid, 5 ml TEOS was dissolved in 40 ml ethanol via sonication followed by which 1 ml D.I. water and 2 ml ammonia was dropped into the solution in stirring condition one after another.
Stored in light glass bottle. 2.5.2: Formation of PANI(CoFe2O4) 0.1g of Nano material and 50ml of Aniline hydrochloride were mixed in a beaker. Then 50ml of Ammonium peroxydisulphate was added drop wise in reaction mixture with constant stirring below 20 oC. After 24 hours the coated sample was filtered, washed and dried at 60 oC in oven and then grinded into a fine powder in agate
Peaks at = 4.1–4.4 ppm are for the protons of the triglyceride moiety and = 5.2–5.5 ppm are for the protons of the CH=CH moiety . Furthermore, the 1H NMR spectrum of PMSO contains peaks in the 5.9-6.4 ppm region corresponding to the protons of the conjugated trienes of -eleosteraric acid. 1H NMR spectra of the resins are shown in Fig. 5. The 1H NMR spectra confirmed the synthesis of the alkyd resins.
Photoluminescence emission analysis (PL) has been primarily employed to investigate the optical properties, oxygen vacancy, migration and capture of photo-induced carriers in the semiconducting Ni/Ti LDH (Fig. 6). It is known that PL emissions of semiconductors are broadly divided into two categories: the band–band PL emission belonging to the electronic transitions from the conduction band (CB) bottom to the valence band (VB) top, and the excitonic PL emissions resulting from the surface oxygen vacancies and defects of semiconductors. For band–band PL emission, the lower the PL intensity, the higher the separation rate of photo-induced electron (eCB−)-hole (hVB+) pair and higher is its photo-induced activity.8, 27, 30 In case of excitonic