Solid state morphology and band gap studies of ETS-10 supported CdS nanoparticles

Engelhard titanosilicate (ETS-10) supported cadmium sulphide (CdS) nanoparticles were synthesized and characterized by various solid state techniques including: XRD, DR UV-Vis, TEM and FESEM. The effect of different synthesis routes of CdS nanoparticles on its physicochemical character was studied. It was observed that CdS nanoparticles prepared by both in situ sulphur reduction (CdS-IS) and reverse micelle (CdS-RM) methods showed similar properties. However, CdS-IS nanoparticles are more feasible and economically practical. The reflectance measurements of the as-synthesized CdS nanoparticles are apparently blue-shifted compared to bulk CdS. This phenomenon of blue-shifted absorption edge has been ascribed to an increase in bandgap energy with a decrease in particle sizes. The bandgap of the as-synthesized CdS samples was calculated from the linear correlation of [F(R) h?]2 and h?. The bandgap of CdS in ETS-10 was noticeably slightly reduced when compared with the as-synthesized CdS (8 nm) due to the formation of cluster arrays on the pores of ETS-10

Ketohydrazone complexes as potential emitting material in OLED

Abstract Ketohydrazone is a molecule that is able to act as a bidentate ligand through the O of C=O and N of N=C in the molecule. Three ketohydrazone ligands had been fully synthesized through the condensation reaction between 2- hydroxynaphthaldehydes with various hydrazides: salisylic hydrazide, benzyhydrazide and 2-furoic acid hydrazide in a 1:1 stoichiometry. The ligands had been characterized using infrared, 1HNMR and ultraviolet-visible spectrometer. Complexation reaction between all ligands and metals, with a stoichiometry of 1:2 for Zn (II) : ligand and 1:3 for Al(III) : ligand were carried out. All six complexes obtained were characterized using FTIR and UV-Vis spectrometer. The fluorescence properties of each ligands and complexes were investigated using luminescence spectrofluorometer excited at 406 nm. It was found that the compounds emitted blue light at ? max = 470 nm. Results showed that all the ligands and molecules synthesized have the fluorescence properties and complexation with metal enhanced the intensity of the fluorescence. It was observed that complex of Al(NDB)3 showed the best potential as an emitting material for OLED as it has the highest fluorescence intensity compared to others. Abstrak Ketohidrazon merupakan sebatian molekul yang berupaya berfungsi sebagai ligan bidentat melalui O daripada C=O dan N daripada N=C di dalam molekulnya. Tiga ligan ketohidrazon telah berjaya disintesis melalui proses kondensasi antara 2- hidroksinaftaldehida dan beberapa kumpulan hidrazida, salisilik hidrazida,, 2-furoik hidrazida, dan benzihidrazida.mengikut nisbah stoikiometri 1 : 1. Semua ligan yang telah disintesis dicirikan melalui spektroskopi IR, UV-Vis dan 1H-RMN. Tindak balas pengkompleksan antara ligan yang telah disintesis dengan dua logam yang berasingan, iaitu aluminium dan zink telah dijalankan dengan nisbah ion ligam : ligan 1 : 3 bagi pengkompleksan dengan aluminium dan 1 : 2 bagi pengkompleksan dengan zink. Enam kompleks yang terhasil dicirikan melalui spektroskopi IR dan UV-Vis. Ciri-ciri pendarfluor bagi tindak balas pengkompleksan dan ligan yang terhasil telah dikaji menggunakan spektrometer pendarfluor pada panjang gelombang pemancaran 405nm. Didapati sebatian-sebatian tersebut memancarkan cahaya biru pada ? max = 470 nm. Hasil yang diperolehi menunjukkan bahawa semua ligan dan kompleks yang disintesis menunjukkan sifat pendarfluor dan pengkompleksan dengan logam dapat meningkatkan keamatan pendarfluornya.. Kompleks Al(NDB)3 menunjukkan potensi yang terbaik sebagai bahan pemancar dalam diod pemancar cahaya organik (OLED) memandangkan kompleks ini menunjukkan keamatan pendarfluor yang tertinggi

Preparation and aggregation-induced emission of new 1,3,5-triazine-2,4,6-tricarboxamide with liquid crystal properties

The combination of aggregation-induced emission (AIE) and liquid crystal properties generates solid-state efficient luminescent liquid crystal materials.Here in, we reported the synthesis of 1,3,5-triazine-2,4,6-tricarboxamide and utilized it as a supramolecular organic motif for the AIE-active liquid crystal material.The compound exhibits high-intensity emission maxima at 417 and 468 nm in the solid state with excitation at 254 nm, whereas it shows weak emission in the solution phase. Also, this compound behaves as liquid crystalline material and shows columnar hexagonal mesophase with endothermic peaks at 73.4oC, 185.6oC, and exothermic peaks were observed at 181.9oC and 66.1oC with focal conic fan shape texture.The thermal data showed that the compound is stable up to 200oC

Biosynthesis of copper(II) oxide nanoparticles using Murayya koeniggi aqueous leaf extract and its catalytic activity in 4-nitrophenol reduction

Copper(II) oxide nanoparticles (CuO NPs) have a wide range of applications as catalysts. The natural abundance of copper and its relatively low cost make it a viable alternative to catalysts that made from expensive precious metals such as platinum and palladium. In this study, a rapid, simple and green method was developed for the synthesis of CuO NPs using an aqueous extract of Murayya koenigii leaves. Several parameters were optimized, namely, the volume of leaf extract, pH, reaction temperature and reaction time. The optimum condition for the biosynthesis was obtained by using 3 mL of leaf extract; 10 mL of 5 mM CuSO4, at pH 11, at room temperature. The biosynthesis was completed within 50 minutes. The synthesized CuO NPs were characterized using Ultraviolet-visible Spectroscopy (UV-Vis), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Transmission Electron Microscope (TEM) analyses. The UV-Vis absorption spectra confirmed the formation of CuO NPs with characteristic peak at 634 nm. The FTIR spectroscopic analysis of the biosynthesized CuO NPs confirmed the surface adsorption of the bioactive components in the leaf extract that acted as the reducing agent and stabilizing agent for the metal nanoparticles. XRD analysis showed a series of diffraction peaks at 2θ of 32.5°, 35.5°, 38.6°, 48.8°, 53.4°, 58.1°, 61.5°, 66.3°, 68.0°, 72.4° and 75.0°, corresponding to (110), (002), (111), (202), (020), (202), (113), (311), (220), (311) and (222),respectively. From TEM images, CuO NPs were of spherical shape with a mean diameter of 8.4 nm. The biosynthesized CuO NPs demonstrated good catalytic activities on the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride, NaBH4 and could be reused three times without significant decreases in the catalytic activities

Gold clusters on thiol-functionalized FE3O4@SIO2 nanoparticles: a novel bioreduced catalyst for oxidation of benzyl alcohol

Bioinspired synthesis of a magnetically recoverable gold nanoparticles (AuNPs) catalysts on Fe3O4@SiO2 support is reported. Firstly, AuNPs was prepared by using the aqueous leaf extract of Polygonum minus (kesum) as a reducing and stabilizing agent. The reduction of Au3+ ions to elemental Au was rapidly occurred and completed within 20 minutes at room temperature. The bioreduction process was monitored by UV-vis spectroscopy and the AuNPs were characterized by FTIR, XRD, TEM, and CV analyses. Then, same bioreduction process was employed in the preparation of Au catalysts supported on thiol-functionalized silica-coated magnetite nanoparticles. The supported Au catalysts were characterized by FTIR, XRD, TEM, XPS and AAS analyses. The performance of bioreduced supported Au catalysts was evaluated in the liquid phase oxidation of benzyl alcohol to benzaldehyde in water at 80o C using H2O2 as oxidant, reaction time of 6 h and 8 mg (4 µmol Au) of catalyst. Under these conditions, benzyl alcohol conversion of 58% and benzaldehyde selectivity of 100% with TON of 4,205 were achieved. The supported Au catalyst is stable and can be recovered and reused for three times without a significant loss in its activity and selectivity

Biosynthesis of gold nanoparticles-peanut shell composite for catalytic reduction of methyl blue

Gold nanoparticles (AuNPs) have been recognized as an active and effective catalyst for many organic transformations. Currently, there is a growing need to develop AuNPs synthesis process that avoids the use of toxic chemicals or high energy requirements. In this research, the aqueous Phaleria macrocarpa (Mahkota dewa) dried fruit extract was used in the biosynthesis of AuNPs immobilized on peanut shell powder. The peanut shell supported AuNPs were characterized by UV-visible spectroscopy (UV-Vis), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetry analysis (TGA), Nitrogen (N2) adsorption-desorption and atomic absorption spectroscopy (AAS) techniques. The biosynthesized AuNPs were characterized by the appearance of a surface plasmon resonance (SPR) band at 534 nm in the UV-Vis spectrum. The XRD, TEM and TGA analytical data of AuNPs/Peanut shell composite indicated that the AuNPs with face-centered cubic (fcc) crystalline shape, mostly spherical and average particle size of 20.00 ± 4.19 nm were well dispersed on the peanut shell powder support. The FTIR analysis suggested that the C=O and OnH groups in the peanut shell powder have a strong affinity to bind and stabilize the AuNPs. The BET surface area of the AuNPs/Peanut shell composite catalyst determined is 35.39 m2 g-1 while the BJH pore volume is 0.035 cm3 g-1 with a pore diameter of 2.07 nm. AAS elemental analytical data showed the Au loading is 0.03 mmol per gram of catalyst. The catalytic performance of the AuNPs/Peanut shell composite was investigated for the reduction of aqueous methyl blue (MB) at room temperature. The reduction of MB obeyed a pseudo-first-order reaction with the highest rate constant of 0.124 min-1. The supported AuNPs/Peanut shell composite catalyst could be easily recovered and reused for at least three times without significant loss of activity

Biosynthesized gold nanoparticles supported on magnetic chitosan matrix as catalyst for reduction of 4-nitrophenol

The design and environmentally-safe synthesis of magnetically recoverable solid-supported metal nanoparticles with remarkable stability and catalytic performance have significant industrial importance. In the present study, we have developed an inexpensive bioinspired approach for assembling gold nanoparticles (AuNPs) in magnetic chitosan network under green, mild and scalable condition. AuNPs were well loaded on the surface of the magnetic support due to the presence of hydroxyl (-OH) and amino (-NH2) groups in chitosan molecules that provided the driving force for the complexation reaction with the Au(III) ions. Reduction of the Au(III) to Au(0) was is achieved by using Melicope ptelefolia aqueous leaf extract. The synthesized magnetic chitosan supported biosynthesized Au nanocatalyst was characterized using Fourier Transform Infrared (FT-IR), Carbon, Hydrogen and Nitrogen (CHN), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD) and Atomic Absorption Spectroscopy (AAS) analyses. FTIR spectrum of magnetic chitosan showed peaks at 1570 cm-1, which indicate for N-H bending vibration and at 577 cm-1 which designates the Fe-O bond. CHN analytical data further supported the coating of chitosan onto the magnetite. TEM analysis showed an amorphous layer around the magnetite core, proving the coating of chitosan on the magnetite surface and the average particle size of AuNPs calculated was 7.34 ± 2.19 nm. XRD analysis showed six characteristics peaks for magnetite, corresponding to lattice planes (220), (311), (400), (422), (511) and (440) in both the magnetite and magnetic chitosan samples (JCPDS file, PDF No. 65-3107). Meanwhile, XRD analysis of catalyst showed characteristic peaks of AuNPs at 2 (38.21°, 44.38°, 62.2°, 77.32° and 80.76°), which correspond to (111), (200), (220), (311) and (222) lattice planes (JCPDS file, PDF No.04-0784). AAS analysis showed the loading of AuNPs as 5.4%. The rate constant achieved for the reduction of 4-nitrophenol to 4-aminophenol in the presence of hydrazine hydrate using 10 mg of catalyst was 0.0046 s-1. The magnetic chitosan supported AuNPs is effective as catalyst for the reduction of 4-nitrophenol

Single-step in situ seed-mediated biogenic synthesis of Au, Pd and Au-Pd nanoparicles by etlingera elatior leaf extract

The rapid formation of stable Au-Pd bimetallic nanospheres are based on a single-step, seed-mediated, growth method using Etlingera elatior leaf extract as a reducing, stabilizing and capping agent. The success of this synthesis is attributed to reduction potential difference of Au and Pd, where Pd initially form seeds in the reaction mixture, followed by growth of Au around the Pd seeds forming Au-Pd bimetallic nanoparticles. Consequently, monometallic Au nanoparticles with mixtures of shapes can be well controlled. The used of Etlingera elatior as a reducing agent is a simple one-pot environmentally friendly reaction, non-toxic and safe method without the need of additional surfactant, capping or stabilizing agent. The synthesized Au-Pd, Au and Pd nanoparticles were characterized via UV-vis, FTIR, XRD, CV, TEM and EDX analysis. TEM analysis revealed that Au-Pd nanoparticles consisted of only nanospheres with mean size of 17.8 ± 9.9 nm, as opposed to the Au nanoparticles that have mixtures of anisotropic nanoshapes with mean size of 15.8 ± 6 nm. FTIR spectroscopic analysis of the biosynthesized Au, Pd and Au-Pd nanoparticles confirmed the surface adsorption of the bioactive components in the leaf extract that acted as the reducing agent and stabilizer for the metal nanoparticles

Preparation and Characterizations of In0.1SnxZn0.85-2xS Powder Photocatalysts for Hydrogen Production under Visible Light Irradiation

A series of In0.1SnxZn0.85-2xS solid solutions was synthesized by hydrothermal method and employed as photocatalyst for photocatalytic hydrogen evolution under visible light irradiation. The structures, optical properties and morphologies of the solid solutions were studied by X-ray diffraction, diffuse reflectance UV–visible spectroscopy and field emission scanning electron microscopy. From the characterizations, it was confirmed that In0.1SnxZn0.85-2xS solid solution can be obtained and they have nano-sized particles. The highest photocatalytic activity was observed on In0.1Sn0.03Zn0.79S photocatalyst, with average rate of hydrogen production 3.05 mmol/h, which was 1.2 times higher than the In0.1Zn0.85S photocatalyst

High activity of Ag-doped Cd0.1Zn0.9S photocatalyst prepared by the hydrothermal method for hydrogen production under visible-light irradiation

Background: The hydrothermal method was used as a new approach to prepare a series of Ag-doped Cd0.1Zn0.9S photocatalysts. The effect of Ag doping on the properties and photocatalytic activity of Cd0.1Zn0.9S was studied for the hydrogen production fromwater reduction under visible light irradiation. Results: Compared to the series prepared by the co-precipitation method, samples prepared by the hydrothermal method performed with a better photocatalytic activity. The sample with the optimum amount of Ag doping showed the highest hydrogen production rate of 3.91 mmol/h, which was 1.7 times higher than that of undoped Cd0.1Zn0.9S. With the Ag doping, a red shift in the optical response was observed, leading to a larger portion of the visible light absorption than that of without doping. In addition to the larger absorption in the visible-light region, the increase in photocatalytic activity of samples with Ag doping may also come from the Ag species facilitating electron–hole separation. Conclusion: This study demonstrated that Ag doping is a promising way to enhance the activity of Cd0.1Zn0.9S photocatalyst