Dealloyed Ruthenium Film Catalysts for Hydrogen Generation from Chemical Hydrides

Thin-film ruthenium (Ru) and copper (Cu) binary alloys have been prepared on a Teflon™ backing layer by cosputtering of the precious and nonprecious metals, respectively. Alloys were then selectively dealloyed by sulfuric acid as an etchant, and their hydrogen generation catalysts performances were evaluated. Sputtering time and power of Cu atoms have been varied in order to tailor the hydrogen generation performances. Similarly, dealloying time and the sulfuric acid concentration have also been altered to tune the morphologies of the resulted films. A maximum hydrogen generation rate of 35 mL min-1 was achieved when Cu sputtering power and time were 200 W and 60 min and while acid concentration and dealloying time were 18 M and 90 min, respectively. It has also been demonstrated that the Ru content in the alloy after dealloying gradually increased with the increasing the sputtering power of Cu. After 90 min dealloying, the Ru to Cu ratio increased to about 190 times that of bare alloy. This is the key issue for observing higher catalytic activity. Interestingly, we have also presented template-free nanoforest-like structure formation within the context of one-step alloying and dealloying used in this study. Last but not least, the long-time hydrogen generation performances of the catalysts system have also been evaluated along 3600 min. During the first 600 min, the catalytic activity was quite stable, while about 24% of the catalytic activity decayed after 3000 min, which still makes these systems available for the development of robust catalyst systems in the area of hydrogen generation. © 2017 by the authors

Printable solar cells

This book provides an overall view of the new and highly promising materials and thin film deposition techniques for printable solar cell applications. The book is organized in four parts. Organic and inorganic hybrid materials and solar cell manufacturing techniques are covered in Part I. Part II is devoted to organic materials and processing technologies like spray coating. This part also demonstrates the key features of the interface engineering for the printable organic solar cells. The main focus of the Part III is the perovskite solar cells, which is a new and promising family of the photovoltaic applications. Finally, inorganic materials and solution based thin film formation methods using these materials for printable solar cell application is discussed in Part IV. © 2017 Scrivener Publishing LLC. All rights reserved

Electrical properties and photoconductivity of polyaniline/sulfonated poly(arylene ether sulfone) composite films

Temperature dependent electrical conductivity of the polyaniline-sulfonated poly(arylene ether sulfone) with 35 mol percent sulfonation (PANI-BPS35) composite films were investigated in the temperature range of 80-380 K. These composite films showed semiconductor behavior with the exponential variation of inverse temperature dependence of electrical conductivity. Calculated Mott's parameters showed that variable range hopping mechanism is the dominant transport mechanism for the carriers in low temperature region. Photoconductivity of the PANI-BPS35 composite films having 10, 20, and 40 weight percent conductive filler under various illumination intensities was also studied. Photocurrent of the composite films increased with increasing both polyaniline weight fraction and temperature. Finally, the effect of doping on both electrical conductivity and the photoconductivity of the composite films was investigated

Directly Copolymerized Disulfonated Poly (arylene ether sulfone) Membranes for Vanadium Redox Flow Batteries

For the first time with this study, membranes from directly copolymerized disulfonated poly(arylene ether sulfone) (BPSH 35) were utilized to replace NafionTM in vanadium redox flow batteries (VRFB). Direct copolymerization provided exact control of the degree of disulfonation on the chemical structure. BPSH 35 showed higher proton conductivity (75 mS cm-1), lower vanadium permeability (1.6x10-13 m2 s-1) and better selectivity (4.7x1013 S m-3 s) than N212. The water uptake values for N212 and BPSH 35 membranes were 28 and 40 % by weight, respectively. Higher proton conductivity and water uptake were observed due to the higher ion exchange capacity (IEC) values of BPSH35. In spite of high water uptake of BPSH35, it showed better resistance to vanadium permeation which was most probably because of the chemically bulky nature of the membrane. Moreover, higher columbic (98.9 %) and energy efficiencies (75.6-90.3 %) at the considered current densities than N212 were achieved. Consequently, BPSH 35 membranes were successfully demonstrated as an inexpensive energy efficient candidate for VRFB

High performance chromium (VI) removal from water by polyacrylonitrile-co-poly (2-ethyl hexylacrylate) and polyaniline nanoporous membranes

This article reports the chromium (VI) removal from water by preparing polyacrylonitrile-co-poly (2-ethyl hexylacrylate) (PAN(92)-co-P2EHA(8)) and polyaniline (PANI) nanoporous membranes at various PANI loadings. It was observed that chromium (VI) rejections of nanoporous membranes are highly concentration and pH dependent. Almost complete chromium removal (99.9%) with higher flux values (120-177 L m-2 h-1) was observed for nanoporous membranes. Moreover, nanoporous membranes were also demonstrated as fouling resistant. Total flux loss was low and a part was attributed to reversible flux loss, which cannot cause any permanent hysteresis and easily overcome with simple washing. Scanning electron microscopy (SEM) studies were performed for identifying cross sectional morphology. It was pointed out that pore size should be small enough for filtration and optimized for higher flux but pores should be functionalized for rejection. Chemical structure, swelling ratios, sheet resistivity, and fracture morphologies of nanoporous membranes were reported. POLYM. ENG. SCI., 2012. (C) 2012 Society of Plastics Engineer

Tailoring the Swelling and Glass-Transition Temperature of Acrylonitrile/Hydroxyethyl Acrylate Copolymers

Novel polyacrylonitrile (PAN)-co-poly(hydroxyethyl acrylate) (PHEA) copolymers at three different compositions (8,12, and 16 mol % PHEA) and their homopolymers were synthesized systematically by emulsion polymerization. Their chemical structures and compositions were elucidated by Fourier transform infrared, H-1-NMR, and C-13-NMR spectroscopy. Intrinsic viscosity measurements revealed that the molecular weights of the copolymers were quite enough to form ductile films. The influence of the molar fraction of hydroxyethl acrylate on the glass-transition temperature (T-g) and mechanical properties was demonstrated by differential scanning calorimetry and tensile test results, respectively. Additionally, thermogravimetric analysis of copolymers was performed to investigate the degradation mechanism. The swelling behaviors and densities of the free-standing copolymer films were also evaluated. This study showed that one can tailor the hydrogel properties, mechanical properties, and T-g's of copolymers by changing the monomer feed ratios. On the basis of our findings, PAN-co-PHEA copolymer films could be useful for various biomaterial applications requiring good mechanical properties, such as ophthalmic and tissue engineering and also drug and hormone delivery. (C) 2009 Wiley Periodicals, Inc. J AppI Polyrn Sci 116: 628-635, 201

Synthesis and Characterization of 2-Hydroxyethyl Methacrylate (HEMA) and Methyl Methacrylate (MMA) Copolymer Used as Biomaterial

A series of poly(methyl methacrylate-co-hydroxyethyl methacrylate) (PMMA-co-PHEMA), copolymers were synthesized by an emulsion polymerization technique. Copolymer compositions were determined by FT-IR and 1H-NMR spectroscopy. It was found that comonomer ratios used in the recipes were comparable within the actual copolymers. Glass transition temperatures (Tg) of PMMA-co-PHEMA copolymers were varied from 119 degrees C to 100 degrees C by increasing HEMA content. Thermogravimetric analysis showed that the copolymers were stable up to 330 degrees C. High intrinsic viscosity values of copolymer resulted in ductile solution-cast films. The hydrophilicity of the films was analyzed by water uptake measurements