scholarly journals Efficient photocatalytic hydrogen production over Ce/ZnO from aqueous methanol solution

2021 ◽  
Vol 10 (4) ◽  
Author(s):  
Ashokrao B. Patil ◽  
Balaso D. Jadhav ◽  
Poonam V. Bhoir
Keyword(s):  
Hydrogen Production ◽  
Hexagonal Wurtzite Structure ◽  
Methanol Solution ◽  
X Ray Diffraction ◽  
Solar Simulator ◽  
Pl Spectra ◽  
Uv Emission ◽  
Visible Spectra ◽  
Uv Visible ◽  
Ce Content

AbstractCe/ZnO crystallites along with bare ZnO were prepared by solution free mechanochemical method and characterized with powder XRD, SEM, EDX, XPS, UV–Visible and Photoluminescence (PL) spectra. The visible light photocatalytic performance of these materials was investigated for H2 evolution with the aqueous 10vol% methanol solution under one sun conditions using solar simulator. X-ray diffraction data suggests the hexagonal wurtzite structure for Ce/ZnO crystallites and the incorporation of Ce4+ ion in ZnO is supported by the shifting of XRD peaks to lower Bragg angles that indicate lattice expansion. With the increase of Ce content in ZnO, the crystallite size of Ce/ZnO decreases and the specific surface area increases. UV–Visible spectra propose the decrease in optical band gap of Ce incorporated ZnO with the increase of Ce content up to 3 mol. %. The XPS analysis supports the incorporation of Ce4+ in Ce/ZnO. The PL spectra propose that, with the insertion of Ce ions into ZnO, intensity of UV emission band decreases that reflects the low recombination rate of photogenerated charge carriers, which is responsible for higher photocatalytic H2 production. The extent of hydrogen production is affected by calcination temperature of Ce/ZnO. 2 mol. % Ce incorporated ZnO calcined at 600 °C produces43 μmolh−1 g−1 of hydrogen.

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

2011 ◽  
Vol 364 ◽  
pp. 238-242 ◽  
Author(s):  
Kimi Melody ◽  
Yuliati Leny ◽  
Mustaffa Shamsuddin
Keyword(s):  
Hydrogen Production ◽  
Visible Light ◽  
Solid Solutions ◽  
Visible Light Irradiation ◽  
Diffuse Reflectance ◽  
Average Rate ◽  
Light Irradiation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Uv Visible

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 nanosized 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.

Structural and Optical Properties of Commercial Microparticle Zinc Oxide

2020 ◽  
Vol 990 ◽  
pp. 302-305
Author(s):  
Razif Nordin ◽  
Nadia Latiff ◽  
Rizana Yusof ◽  
Wan Izhan Nawawi ◽  
M.Z. Salihin ◽  
...  
Keyword(s):  
Room Temperature ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
Xrd Pattern ◽  
X Ray ◽  
Commercial Grade ◽  
Irregular Shapes ◽  
Visible Spectra ◽  
Uv Visible

Commercial grade ZnO were sieved into particle size of 38 to 90 μm at room temperature. X-ray diffraction (XRD) pattern confirms the hexagonal wurzite structure of ZnO microparticles. Irregular shapes of ZnO microparticles were observed by scanning electron microscope (SEM). Fourier transform infrared spectra (FTIR) confirmed the presence of Zn-O band. In addition, Uv-visible spectra (UV-Vis) were empolyed to estimate the band gap energy of ZnO microparticles.

Preparation of Monodisperse ColloidalZnONanoparticles and their Optical Properties

NANO ◽  
2015 ◽  
Vol 10 (05) ◽  
pp. 1550074 ◽  
Author(s):  
Chong Yang ◽  
Limei Tang ◽  
Qingsong Li ◽  
Ailing Bai ◽  
Yanqiu Wang ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Excess Oxygen ◽  
X Ray Diffraction ◽  
Red Emission ◽  
Selected Area Electron Diffraction ◽  
Uv Emission ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Uv Visible ◽  
Size Powder

Monodisperse colloidal zinc oxide ( ZnO ) nanospheres with a narrow size distribution were synthesized via a developed two-stage solution method. We controlled the size of the as-synthesized ZnO nanoparticles by varying the amount of ZnO /ethanol suspension added. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed that the diameter of the as-synthesized ZnO nanoparticles was in the range of 60–140 nm with a polydispersity index less than 5%. On high-resolution TEM images, we clearly observed that the ZnO nanospheres were actually composed of tiny ZnO subunits, several nanometers in size. Powder X-ray diffraction and TEM-selected area electron diffraction analysis showed that the spheres consisted of polycrystalline nanoparticles. The size of the subunits, which was confirmed by ultraviolet (UV)-visible spectroscopy, increased as the amount of ZnO /ethanol suspension added was decreased. A UV emission at about 374 nm was observed, and this emission of ZnO nanoparticles is found to depend on particle size due to the confinement effect. A red emission at about 651 nm, which has been reported for undoped ZnO , appeared due to the excess oxygen on the particles from O – H or C = O groups. The intensity of the red emission increased as the relative oxygen content increased. The formation mechanism of such ZnO nanospheres was also considered.

Silver Doped Nano-Sized Bioglass Ceramics: Synthesis, Characterization and Biocompatibility Studies

2016 ◽  
Vol 860 ◽  
pp. 25-28 ◽  
Author(s):  
Chinnasamy Ramaraj Mariappan ◽  
Narender Ranga
Keyword(s):  
Sol Gel ◽  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Bending Vibrations ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Visible Spectra ◽  
Calcium Phosphosilicate ◽  
Uv Visible

We report on the structural and biocompatibility properties of nanosized calcium phosphosilicate bioglass ceramics doped with 0, 2, 4 and 6 mol% Ag2O. Silver doped bioceramics were synthesized by sol-gel method. The prepared samples were characterized by means of powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV-visible and high resolution transmission electron microscopy. The XRD reveals the glass-ceramic nature of the samples. The FT-IR spectra show the possible stretching and bending vibrations of silicate and phosphate groups. Absorptions in UV-visible spectra reveal the silver embedment as Ag+/Ago form into the glass matrix. nanosize of the glass ceramics is confirmed by HR-TEM analysis. The bioactivity of silver doped bioceramics was investigated by in-vitro method with Dulbecco’s Modified Eagel’s Medium. It confirms the formation of bone-like hydroxylapatite layer formation on the surface of bioceramics.

scholarly journals Influence of Laser Energy and Annealing on Structural and Optical Properties of CdS Films Prepared by Laser Induced Plasma

2020 ◽  
pp. 1307-1312
Author(s):  
Wadaa S. Hussein ◽  
Ala' Fadhil Ahmed ◽  
Kadhim A. Aadim
Keyword(s):  
Optical Properties ◽  
Annealing Temperature ◽  
Laser Energy ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Laser Induced Plasma ◽  
Visible Spectra ◽  
Uv Visible ◽  
Diffraction Patterns

The current study was achieved on the effects of laser energy and annealing temperature on x-ray structural and optical properties, such as the UV-Visible spectra of cadmium sulfide (CdS). The films were prepared using pules laser deposition technique (PLD) under vacuum at a pressure of 2.5×10-2 mbar with different laser energies (500-800 mJ) and annealing at a temperature of 473K. X-ray diffraction patterns and intensity curves for the CdS showed that the formation of CdS multi-crystallization films at all laser energies. The optical properties of the films were studied and the variables affecting them were investigated in relation to laser energy and changes in temperature.

Effect of Coupling Indium Tin Oxide with the TiO2–NaYF4:(Gd, Si) Composite for Photocatalytic Properties

2020 ◽  
Vol 20 (12) ◽  
pp. 7629-7635
Author(s):  
Shielah Mavengere ◽  
Sang-Chul Jung ◽  
Jung-Sik Kim
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Near Infrared ◽  
Visible Region ◽  
Impregnation Method ◽  
Solar Simulator ◽  
Visible Spectra ◽  
Multi Wavelength ◽  
Uv Visible ◽  
Ito Nanoparticles

Indium tin oxide (ITO) nanoparticles were coupled with NaYF4:(Gd, Si) using a TiO2-solution impregnation method. Scanning electron microscopy confirmed that TiO2 and ITO nanoparticles were loaded on the surface of the NaYF4:(Gd, Si) upconversion phosphor. The ultraviolet/visible spectra of the 20 wt.% ITO-NaYF4:(Gd, Si)/TiO2 composites were extended at the absorption edges towards the UV-visible region. The 20 wt.% ITO-coupled NaYF4:(Gd, Si)/TiO2 composites exhibited superior photocatalytic efficiency compared to only NaYF4:(Gd, Si)/TiO2 under near-infrared (NIR) irradiation. Multi-wavelength NIR photons of γ > 760 nm from a Xe solar simulator source induced photo-activation through the NaYF4:(Gd, Si) activator centers. The three-cycle photocatalytic reusability performance of the 20 wt.% ITO-impregnated NaYF4:(Gd, Si)/TiO2 composite was positively enhanced by up to 20% more than that of NaYF4:(Gd, Si)/TiO2.

scholarly journals Synthesis of Ag Nanostructures by Photochemical Reduction Using Citrate-Capped Pt Seeds

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Hyeong-Ho Park ◽  
Xin Zhang ◽  
Yong-June Choi ◽  
Hyung-Ho Park ◽  
Ross H. Hill
Keyword(s):  
Average Diameter ◽  
Uv Exposure ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Photochemical Reduction ◽  
X Ray ◽  
Transmission Electron ◽  
Visible Spectra ◽  
Uv Visible ◽  
Face Centered

A simple synthesis of Ag nanostructures such as nanorods and nanowires has been demonstrated with citrate-capped Pt seeds. UV-visible spectra and photographs of the synthesized solutions at different UV exposure times showed that the citrate-capped Pt seed played a crucial role in the growth of Ag nanostructures. After UV exposure of the colloidal solution for 60 min, the average diameter, length, and aspect ratio of the Ag nanostructures were about 95 nm, 2.1 μm, and 22, respectively. The photochemical reduction is hypothesized to result from photoelectron transfer from adsorbed citrate to Pt nanoparticle seed allowing Ag ions to form Ag nanostructures. Based on X-ray diffraction spectra and transmission electron microscope images, the synthesized Ag nanostructures were a face-centered cubic single crystal with good purity. These results suggest that the photochemical reduction method can provide Ag nanostructures in the presence of citrate-capped Pt seeds at room temperature for anisotropic Ag products.

scholarly journals Effect of Molar Ratio on Structural and Size of ZnO/C Nanocomposite Synthesized Using a Colloidal Method at Low Temperature

2019 ◽  
Vol 19 (2) ◽  
pp. 422
Author(s):  
Siham Lhimr ◽  
Saidati Bouhlassa ◽  
Saidati Bouhlassa ◽  
Saidati Bouhlassa ◽  
Bouchaib Ammary ◽  
...  
Keyword(s):  
Room Temperature ◽  
Optical Band Gap ◽  
Hexagonal Wurtzite Structure ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Colloidal Method ◽  
Uv Visible ◽  
Diffraction Patterns

In this paper we study the effects of different molar ratio R of Zn2+ to OH– (R= nOH–/nZn(II) of the precursor was investigated by varying the amount of NaOH. Samples have been synthesized by the colloidal method at room temperature using (ZnCl2), citric acid (C6H8O9·H2O) and sodium hydroxide (NaOH). The formation of ZnO/C composite was characterized by The X-ray diffraction patterns indicated a high crystallinity and nanocrystalline size of ZnO with hexagonal wurtzite structure. The morphologies of the particles have been studied with a scanning electronic microscopy (SEM). The existence of carbon into the composite was detected by FTIR and EDS. The optical band gap of various ZnO/C composite was calculated from UV-Visible absorption measurement varied in the range 3.301 to 3.282 eV according to R values.

Studies on Polyaniline/Silver Molybdate Nanocomposites

2014 ◽  
Vol 13 (01) ◽  
pp. 1450002 ◽  
Author(s):  
K. Jacinth Mispa ◽  
P. Subramaniam ◽  
R. Murugesan
Keyword(s):  
Oxidative Polymerization ◽  
Hydrothermal Process ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Silver Molybdate ◽  
Visible Spectra ◽  
Ft Ir ◽  
Uv Visible

Silver molybdate nanoparticles were successfully prepared by the hydrothermal process. Polyaniline–silver molybdate nanocomposites were prepared by in situ chemical oxidative polymerization technique. Silver molybdate nanoparticles and the polymer samples were characterized by conductivity studies, Fourier transform infrared spectra (FT-IR), UV-visible spectra, photoluminescence spectra, X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The electrical conductivity of PANI- Cl - increases when doped with silver molybdate nanoparticles and follows the percolation threshold.

A Preliminary Study on the Effect of Pandanus amaryllifolius Extract as Green Stabilizer to the Growth of Nanostructured ZnO

2020 ◽  
Vol 990 ◽  
pp. 277-282
Author(s):  
Rabiatuladawiyah Md Akhir ◽  
Siti Zulaikha Umbaidilah ◽  
Nurul Afaah Abdullah ◽  
Mohamad Rusop Mahmood ◽  
Zuraida Khusaimi
Keyword(s):  
Cost Effective ◽  
Hexagonal Wurtzite Structure ◽  
Zno Nanoparticle ◽  
X Ray Diffraction ◽  
Green Method ◽  
Visible Absorption ◽  
X Ray ◽  
Preliminary Study ◽  
Uv Visible ◽  
Average Size

Nanostructured zinc oxide (ZnO) were successfully prepared by using phyto assisted solution immersion process. ZnO were grown on a glass substrate coated with ZnO nanoparticle thin-film as seed layer at annealing temperature of 450°C. The fabricated nanostructured ZnO exhibit absorption at ∼375 nm as revealed from the UV-visible absorption spectrum, and it is comparable with ZnO nanostructured synthesized from hexamethylenetetramine (HMTA). X-ray diffraction (XRD) measurement revealed a sharp peak corresponding to the hexagonal wurtzite structure of nanostructured ZnO. Field emission scanning electron microscopy (FESEM) showed average size of ZnO at 24.15 nm slightly smaller compared to synthesized from HMTA; 30.54 nm. It should also be highlighted that the needs of using this alternative green method are due to the advantages of low working temperature and cost-effective, and with the least possible damage to the environment.

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