Journal of Nanoanalysis

Number 3, 2014

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Comparative Study of Nanostructured Zr-Fe2O3 and CNT Modified Zr-Fe2O3 Thin Films for Photo Electrochemical Generation of Hydrogen

Authors: Vibhuti Yadav, Sadhana Tyagi, Devbrat Pundhir, Saral Kumar Gupta

Abstract

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Nanostructured hematite thin films are doped with zirconium successfully and also modified by introducing CNT using sol-gel method for their implementation as photo-electrode in photoelectrochemical (PEC) cell for hydrogen generation. XRD, UV-visible spectroscopy and PEC study techniques are used to characterize the thin films. The PEC responses of thin films are improved by introducing carbon nanotubes (CNT).

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Tailoring the Energy Band Gap of Transition Metal Doped TiO2 Thin Film

Authors: M. Khalid Alamgir, M. Zaka Ansar, M. Shoaib,G. Murtaza, Javaid Ahsan Bhatti, Usman Asghar

Abstract

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Water splitting for hydrogen production under sunlight using TiO2 as photo catalyst provides a better route for solar energy and attracts the attention of many researchers. The photo catalytic activity of TiO2 under sunlight irradiation depends on the band gap energy. The transition metal doped TiO2 shows an edge over TiO2 in optical absorbance and photo catalytic activity. Thin film of Cr doped TiO2 was deposited by Electron beam evaporation deposition process on glass substrate, the band gap of sample was measured with UV-Vis spectroscopy. In order to provide theoretical ground to our experimental band gap results the first principle (ab-initio) calculation was performed using the computer code WIEN2K with Full Potential Linearized Augmented Plane Wave method (FP-LAPW) based on the density functional theory (DFT).

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Production of Hydrogen and Synthesis gas via Cu-Ni/Al2O3 catalyzed gasification of bagasse in supercritical water media

Authors: Reza Mehrani, Ahmad Tavasoli, Mohammad Barati, Ali Karimi, Masoumeh Ghalbi Ahangari

Abstract

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Bagasse as a real biomass was converted to hydrogen rich gas via catalytic supercritical water gasification process. To find the effect of Cu on selectivity of products, Cu promoted Ni-γAl2O3 catalysts were prepared with 1 to 20wt% Ni and 0.5 to 10wt% Cu loadings via impregnation method. Catalysts were characterized by ICP, BET, XRD, H2 chemisorption and TEM technique as well CHNS analysis was carried out for elemental analysis of bagasse. The biomass supercritical water gasification process was performed in a batch micro-reactor at 400oC and 240 bars. The total gas yield increased with increasing in Ni and Cu loadings up to 15wt% Ni and 7.5 wt% Cu and became approximately constant. The catalytic process increased hydrogen yield to 9.5, CO yield to 2.2 and light hydrocarbons to 0.59 mmol/g bagasse. Total H2 selectivity (THS) ratio increased with increasing in Ni and Cu loading reached a maximum at 15%wt Ni and 7.5%wt Cu and then began to decrease.

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Wet chemical synthesis and physical characterization of doped CeO2 nanoparticles

Authors: J. Jasmine Ketzial, A. Samson Nesaraj

Abstract

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Solid electrolytes based on doped cerium oxide, Ce(M)O2-δ (M = rare-earth cations), are of considerable interest for potential use in low temperature solid oxide fuel cells (LTSOFCs) due to its higher ionic conductivity than YSZ based solid electrolyte. In this research work, crystalline, pure Ce1-xMxO2-δ (where M = Gd or Sm, x = 0.10 or 0.20) based nanoparticles were prepared by chemical precipitation method in presence of surfactant (polyvinyl pyrollidone). The intermediate compound (mixture of hydroxides) was subjected to TGA/DTA in order to find out the temperature at which the pure phase product is formed. Then, the as prepared materials were heat treated systematically at 300, 450 and 600o C for 2 h each to get phase pure materials. The resultant nanoparticles were subjected to physical characterization techniques such as, XRD, FTIR, particle size analysis and SEM. XRD results confirmed that all the powders had single-phase fluorite structure. Characteristic vibration mode of CeO2 was proved by FTIR. The presence of nanoparticles (50 – 100 nm) in the prepared materials was found out by particle size measurements and SEM. The results of physical characterization of the above materials are found to be good for application as alternate electrolytes in SOFC. However, these materials can be considered as suitable alternate electrolytes in LTSOFC systems only after studying their electrical characteristics.