Ujjwal K Bhagat; Anuraj S. Kshirsagar; Ashish Gautam; Pawan K Khanna
Abstract
The present article highlights a simple and effective method for preparation of nano-fluid (NF) by employing long carbon chain fatty acid, PVP and ethylene glycol stabilized anatase phase TiO2. The so-prepared nano-fluid (0.5 wt. %) was employed for advanced oxidative photo-degradation of MB with different ...
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The present article highlights a simple and effective method for preparation of nano-fluid (NF) by employing long carbon chain fatty acid, PVP and ethylene glycol stabilized anatase phase TiO2. The so-prepared nano-fluid (0.5 wt. %) was employed for advanced oxidative photo-degradation of MB with different concentrations (1-5 mL) under short (254 nm) and long UV (365 nm) irradiation against various concentrations (5, 15, 25 ppm). The maximum degradation efficiency observed was 88% and 71% under short and long UV irradiation respectively. The photocatalytic degradation of the MB was also studied by reaction kinetics. Initially, titania nanoparticles (NPs) were synthesized and characterized using various advanced tools such as UV-Visible, FTIR, Raman spectroscopy, BET, XRD, SEM/EDAX, TEM etc. for its size, surface area and morphological understanding.
P. Muthirulan; C. K. N. Devi; M. M. Sundaram
Abstract
Simple and proficient methodology has been proposed for the preparation of hybrid photocatalyst based on titanium dioxide (TiO2)-graphene (GR) nanocomposite for acid orange 7 (AO7) dye degradation under UV irradiation. High Resolution Transmission Electron Microscopy (HRTEM) and Scanning Electron Microscopy ...
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Simple and proficient methodology has been proposed for the preparation of hybrid photocatalyst based on titanium dioxide (TiO2)-graphene (GR) nanocomposite for acid orange 7 (AO7) dye degradation under UV irradiation. High Resolution Transmission Electron Microscopy (HRTEM) and Scanning Electron Microscopy (SEM) studies revealed that TiO2 nanoparticles were uniformly dispersed on GR surface. TiO2-GR hybrid nanocomposite has also been characterized by Ultraviolet Diffusive Reflectance Spectroscopy (UV-DRS), Raman spectroscopy and X-ray diffraction (XRD) studies. Electrochemical Impedance spectroscopy (EIS) measurement revealed that the incorporation of GR with TiO2 nanoparticles significantly enhanced the electrical conductivity.The peak intensity of PL spectra of GR containing catalysts are lower than that of pristine TiO2, indicating that the electron–hole recombination rate of self-trapped excitations in TiO2 is reduced by the introduction of GR. The photocatalytic degradation measurements demonstrated that the TiO2-GR composites exhibited an enhanced photocatalytic activity for AO7 degradationunder UV irradiation compared to pure TiO2. This may due to greater adsorptivity ofdyes, extended light absorption and increased charge separation efficiency due to excellent electricalproperties of graphene and the large surface contact between graphene and TiO2 nanoparticles. Therefore, the TiO2-GR composites can be widely used as a ternary composite photocatalyst for treating the organic contaminant in the field of environmental protection.
Omkar S. Kushwaha; C. V. Avadhani; R. P. Singh
Abstract
High temperature polymer electrolyte membrane fuel cells (HTPEMFCs) are energy efficient systems with the potential to address all energy issues of present and future generations. Polybenzimidazole (PBI) based high temperature fuel cells are subject of high importance because PBI membranes are proved ...
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High temperature polymer electrolyte membrane fuel cells (HTPEMFCs) are energy efficient systems with the potential to address all energy issues of present and future generations. Polybenzimidazole (PBI) based high temperature fuel cells are subject of high importance because PBI membranes are proved to be one of the best candidates for high temperature fuel cell applications. The stability of PBI membranes has been identified as crucial issue for the long-term durability under oxidative conditions of fuel cells. The present investigation highlights the photo-oxidative degradation studies accomplished on polybenzimidazole based poly(2,2'-butylene-5,5'-bibenzimidazole) (PBIB) membranes. The PBIB polymer membranes are found suitable for both in high temperature fuel cells as well as other high temperature applications. In this research article, PBIB membranes were photoirradiated under polychromatic UV rays (λ > 290 nm). The photo-oxidative degradation of membranes was characterized by Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscopy (SEM). FT-IR results showed significant amount of photo-oxidation and chemical degradation in fuel cell membranes which is proposed to be initiated by free radical mechanism. SEM images revealed development of nano-dimensional cracks and holes on surface of membranes which indicate structural and morphological degradation. The present study showed better results of accelerated photo-degradation as compared to the oxidative degradation results already reported in literature obtained chemically and thermally. Hence, the proposed photo-oxidative degradation method may be useful in determining stability, life time expectancy and degradation mechanism of fuel cell and other high performance membranes.
