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Exploring non-platinum group metal (n-PGM) based efficient oxygen reduction reaction (ORR) electro-catalysts is highly important for realizing advancement in sustainable next generation-alkaline anion exchange membrane fuel cells (AAEMFCs). Herein, we demonstrate a new “hierarchical shape tuning approach” for the synthesis of controlled sized and shaped non-PGM based Ag ORR electro-catalysts with surface active nano-islands. Hierarchical shapes ranging from spherical (S-AgNs), worm-in-sphere, sphere-in-worm and vermiform (worm-like) Ag nanostructures (V-AgNs) were obtained by precisely varying the ratios of capping agent to dual reducing agents in water at ambient conditions. Compared to S-AgNs, V-AgNs revealed a higher mass normalized ORR Tafel activity (0.303 A mgAg−1 at 0.9 V), onset (1.06 V) and half wave (0.78 V) potentials and higher retention of limiting current density (>88%) after 5000 cycles in 0.5 M potassium hydroxide (KOH) solution attributable to their unique worm like morphology with surface active nano-islands and support free-nature enabled better catalyst utilization. In a fully “non-PGM AAEMFC” (n-PAAEMFC), V-AgNs exhibited the highest fuel cell activity of 115.6 mW cm−2 and stable short-term durability (∼240 h) compared to S-AgNs (41.3 mW cm−2) and previously reported fully n-PAAEMFCs indicating their potential use in next-generation alkaline fuel cells.

Aziridinofullerene-porphyrin (C60-TPP) dyad was synthesized using triethyl phosphite mediated [2+1] cycloaddition reaction. Structural elucidation of the compound was carried out using NMR and FT-IR spectroscopic methods. The synthesized C60-TPP was further characterized using UV-Vis absorption and photoluminescence emission studies. An optical study of the synthesized compound shows absorption maxima at 424 nm, around 516, 550, and 593 nm with small broad absorption peaks at 360 and at 480 nm. Photoluminescence studies of the compound shows emission maxima at around 597, 652 and 717 nm. Electrochemical studies of the compound shows oxidation potentials at 0.30, 0.52, 0.74 V and reduction potentials at−1.69,−2.07 and−2.42 V with respect to internal Fc/Fc+ reference corresponding to porphyrin and fullerene C60 moiety in the compound and the formation of C60-TPP. Furthermore, the absence of obtain XPS peaks corresponding to nitro group in C60-TPP confirms the conversion of nitro group to aziridine group.

Poly(fluorene-alt-benzothiadiazole) having 5 and 10% equivalent meso-tetraphenylporphyrin (m-MTPCC) linked through oxyethylene spacer in carbazole (P2, P3) and the parent poly(9,9-di-hexylfluorene-alt-2,1,3-benzothiadiazole) (P1) were synthesized using Suzuki polymerization reaction. These polymers were characterized using FT-IR, 1H NMR, TGA and gel permeation chromatography. The synthesized polymers are soluble in common organic solvents and are found to be thermally stable. Weight average molecular weights of the polymers were 51.895, 71.224 and 34.789 kDa for P1, P2 and P3, respectively. These copolymers (P2 and P3) shows absorption maxima at around 320, 422, 452 nm and emission maxima at 540 nm in solution, whereas in film state, these polymers (P2 and P3) shows absorption maxima at around 322, 422, 466 and 554 nm and emission at around 539, 654 and 718 nm. The photoluminescence emission at 648 and 720 nm when excited at 320 nm shows that energy transfer from polymer backbone to porphyrin. Surface morphology, optical absorption and emission properties of these polymers with PCBM were also studied. Electrochemical characterization of these polymers shows deep HOMO levels for P2 and P3 when compared with parent polymer and the details are reported.

Herein, we report a simple and elegant aqueous synthesis of Pd100-xPtx (x=5, 10, 15 and 20) nano-porous structures (NPoS) derived from Pd100-xMn2x (x=5, 10, 15 and 20) nano-alloys. Pd100-xPtx/C NPoS exhibit enhanced oxygen reduction reaction (ORR) activity along with higher retention of figure of merit in the presence of methanol compared to HiSPEC Pt/C catalyst. The ORR mass and specific activity values of Pd100-xPtx/C NPoS are high and exceed the U.S. department of energy (DOE) 2017–2020 targets. The enhanced methanol tolerance and ORR activity of Pd100-xPtx/C NPoS is attributed to their unique surface active Pd−Pt islands on nano-porous Pd. Direct methanol fuel cell performance studies employed using Pd85Pt15/C NPoS as cathode material (0.4 mgPt/cm2) and HiSPEC PtRu/C NPs as anode material (0.2 mgPt/cm2) shows improved direct methanol fuel cell (DMFC) single cell activity at low Pt loading and the results are presented.

Gold-platinum nano-porous structures (Au100-xPtx NPoS) with unique surface enriched Au−Pt islands are synthesised through a galvanic replacement strategy from Au100-xAg2x nano-alloys with ultra-low platinum loading (x=1.25, 2.5 and 5). Formic acid oxidation reaction (FAOR) on Au100-xPtx/C NPoS shows a distinct peak at around 0.5 V related to CO2 formation. A characteristic peak at around 1.5 V increases with increasing FA concentration owing to the direct FAOR by nano-porous Au centers. FAOR peaks and If/Ib peak current ratios indicates that, Au100-xPtx/C NPoS facilitates direct FAOR pathway unlike HiSPEC Pt/C (dehydration pathway). Based on the enhanced chrono-amperometric response, Tafel behaviour and mass activity values, Au97.5Pt2.5/C NPoS (5.5 A/mgPt) reflects as the optimal catalyst for efficient FAOR. The intriguing catalytic role of surface enriched Au−Pt islands present on nano-porous Au greatly helps in determining the superior FAOR activity in Au97.5Pt2.5/C NPoS towards direct dehydrogenation pathway at ultra-low Pt content compared to other NPoS and HiSPEC Pt/C catalysts.

We demonstrate electrochemical cycling-induced reduction of MoO3 to monoclinic molybdenum dioxide and molybdenum sub-oxides (MoO3-x), which exhibit excellent electrochemical hydrogen evolution reaction (HER) activity. The conversion of MoO3 during cycling was probed; after 250 cycles, the redox peaks were found to diminish with an onset potential shift and increased HER current density. At 400 cycles, the insertion/deinsertion processes observed in the initial cycles are completely absent and the HER current density is enhanced to the maximum. The effect of MoO3 morphology and size on the electrochemical reduction of MoO3 was also studied.

Five new polymers were synthesized by Suzuki coupling reaction using 9,9-dihexylfluorene-2,7-diboronic acid and 3,3′-dibromo-4,4′-dialkoxybiphenyl as the starting materials. The synthesized alternating copolymers were characterized using gel permeation chromatography, 1H and 13C NMR, FT-IR, optical absorption and emission spectroscopic techniques. The thermal behavior of these polymers was analyzed using thermal gravimetric analysis and temperature modulated differential scanning calorimetric studies. The thermal studies show all the polymers were stable up to 300 °C and the glass transition temperature depends on the alkyl chain length. All the polymers have absorption around 330 nm in solution as well as in film, whereas the polymers have emission around 390 nm in both solution and film. Absorption and emission properties of the synthesized materials are not significantly different in solution, but are dramatically different as thin films at different annealing temperatures.

Poly(fluorene-alt-carbazole) appended with meso-tetraphenylporphyrin (MTPPC) linked through oxyethylene spacer and the parent poly(N-hexyl-2,7-carbazole-alt-9,9-di-n-hexyl fluorene) (P1) were synthesized and characterized. Optical absorption properties of the polymers containing 5% of MTPPC (P2) and 10% of MTPPC (P3) in the polymer backbone show extended optical absorption toward long wavelength compared to the parent polymer P1. Optical absorption studies of the polymers showed that polymer P1 has absorption at 384 nm in solution, whereas polymers P2 and P3 have absorption at 384 nm corresponding to polymer backbone and soret band at 421 nm with Q bands at around 518 and 554 nm in solution. P1 shows photoluminescence emission around 417 nm, whereas P2 and P3 fall around 656 nm. Thermal, electrochemical, and quenching studies of the polymers have been studied and the details are reported.

Degradation of high-density polyethylene (HDPE) films blended with 0.5, 1.0, and 2.0% metal ions (MIs, chromium = 36%, silicon = 8%, aluminum = 4%, and chlorine = 2%) and 5, 10, and 20% potato starch were studied under two different abiotic treatment conditions (they were either heated to 70�C or exposed to UV at 300-400 nm) for a period of 100 days. The addition of metals did not affect the mechanical strength of the polymer, whereas starch blending did. The latter turned the polymer yellow. HDPE with MIs exhibited higher levels of oxidation than the other samples. UV treatment affected the mechanical strength of the MI-blended HDPE more than the other additive or the thermal treatment. The formation of extractable oxygenated compounds and unoxidized low-molecular-weight hydrocarbons increased with increasing concentration of additives in HDPE. The surface energy in all cases increased, this indicated that the polymers turned hydrophilic. The maximum weight loss (28%) was seen in the 2% MI-blended HDPE exposed to UV followed by the 20% starch-blended polymer exposed to heat (24%). These results indicate a synergy between blending and the treatment strategy, this also suggests an optimal waste-disposal strategy. � 2012 Wiley Periodicals, Inc.

Hexagonal BiPO4·xH2O and Bi0.95Eu0.05PO4·xH2O nanoparticles were synthesized by a polyol-mediated method employing diethylene glycol. The powder X-ray diffraction revealed the phase purity and isostructural nature of both undoped and Eu3+-doped BiPO4. The monoclinic Bi0.95Eu0.05PO4 was obtained by heating the hexagonal Bi0.95Eu0.05PO4·xH2O at 600 °C. The microscopical characterization revealed the formation of nanocrystalline materials. Water molecules present in the bismuth precursor favoured the formation of hexagonal phase at low temperature. The role of DEG molecules in arresting the particle growth during the phase transformation of Bi0.95Eu0.05PO4 from hexagonal to monoclinic was observed. The synthesized materials were characterized using different spectroscopic techniques such as FT-IR, Raman, 31P MAS-NMR, DRUV-Vis and PL. The difference in the crystal structures and symmetries is clearly reflected in the spectral results of hexagonal and monoclinic Bi0.95Eu0.05PO4. The structure-property relations were studied to derive its importance from both fundamental and technological aspects.

We are reporting the preparation and characterization of nano-titanium dioxide and silica. The corrosion resistance performance of these nanopigments in silicone as well as silicone–polypyrrole Interpenetrating Polymer Network has been evaluated by impedance spectroscopy. The capacitance and resistance exerted by this nanocomposite coating were compared with the microcomposite coating and found that the nanocomposite coatings has the resistance in the order of 108 Ω cm2 in 3% sodium chloride solution, which is more than the microcomposite coating. The comparison of heat resistance performance of these composite coatings indicates that nanocomposite coatings exhibit higher heat resistance property than the microcomposite coatings.

Divalent europium-activated alkaline-earth-metal chlorophosphate luminophores (MCAP:Eu 2+ ; M=Ca, Sr, Ba) have been prepared by self-propagating high-temperature (SPHT) synthesis in one pot employing the corresponding nitrates/chlorides, urea and diammonium hydrogen phosphate. The synthesized materials have been characterized by X-ray diffraction, photoluminescent emission spectroscopy, thermogravimetry, scanning electron microscopy and particle size analysis. The formation of chloroapatite depends on the nature of acid used in the combustion mixture. The photoluminescent emission efficiency and particle size distribution are found to depend on the amount of metal chloride used and on the sintering temperature. The results obtained are discussed with respect to the processing method employed.

SUMMARYIn conclusion, first time we report that SnCl 2 candope PAni-EB form by producing SnO 2 and HCl.The formed HCl doped the quinoid segments of theE.B structure in a conventional way to form conduct-ing PAni salt and SnO 2 is deposited on the surfaceof the polymer concomitantly to give conductingPAni-SnO 2 composite. In this method of preparation(composite A), tin oxide particles are deposited onPAni fibers. In the case of in situ polymerization(composite B), the composite is a homogeneous mix-ture of some free SnO 2 particles, SnO 2 on PAni andas well as SnO 2 encapsulated/embedded in PAni.The conductivity of the samples A and B increasedsignificantly due to the presence of SnO 2 nanopar-ticles, where the tin oxide particles are crystallizedin tetragonal (t-SnO 2 ) structure. In this study, it isalso established that composite A and B exhibitedimproved electrochemical property compared withpure PAni. The composite B showed enhancedpseudo capacitance as high as 219 F g 1 .The authors thank the directors of IICT and CECRIfor their constant encouragement, unstinted support.References

Recently there has been a considerable focus on the synthesis of nitrogen functionalized graphene for energy storage and conversion. Herein, we report a simple, economical and facile process for the synthesis of nitrogen containing graphene composite which can be scaled up for mass production by using a nitrogen containing organic compound, ethylenediaminetetraacetic acid (EDTA) and graphene oxide as precursors. From the XRD studies, the increase in the interlayer distance between the graphene sheets confirms the functionalization of graphene sheets and the FT-IR spectroscopic analysis revealed the presence of N-containing functional groups in N-doped graphene sheets. XPS analysis confirms the chemical nature of N-containing functional groups, and TG analysis showed the amount of EDTA loaded on the graphene sheets. This composite exhibits a large specific capacitance of 290 F g−1 at 0.1 A g−1 with a capacitance retention of 67% and 58% at high current densities of 10 and 20 A g−1, respectively, thereby showing superior rate capability. In addition, it showed long-term electrochemical stability through 6000 charge–discharge cycles even at a high current density of 5 A g−1 with a specific capacitance loss of 2%.

A graded nano-alloy of Au100−xPtx (x = 7, 15, 23, 32, 40, 51, 62, 73 and 86) nanoparticles (NPs) formed by co-reduction of HAuCl4 and H2PtCl6 and the details are presented in this work. Au100−xPtx NPs were characterized using surface plasmon resonance (SPR) absorption spectroscopy and transmission electron microscopy (TEM). The NPs were dispersed in Vulcan carbon (Au100−xPtx/C) and annealed at 250, 400, 600 and 800 °C. The as-formed and annealed materials were characterized using TEM, high resolution transmission electron microscopy (HR-TEM), powder X-ray diffraction (XRD), cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS). The CV studies indicate excess Pt on the surface, which is corroborated by XPS and HR-TEM results. The XRD data show that Vegard's law is obeyed by the as-formed material and the materials annealed at 250 and 400 °C, indicating that these materials are not nano-alloys. The studies clearly indicate that the formation of Au100−xPtx NPs is kinetically controlled rather than being controlled by the thermodynamic stability. The results demonstrate the formation of graded alloys of Au100−xPtx NPs. Pt excess in the graded nano-alloy is reflected favourably in the electrochemical oxidation of small organics. In the methanol oxidation reaction (MOR), the peak current value per mg of Pt increases as a function of x, reaches a maximum value at x = 23 and the ratio of forward current to reverse current for MOR reached an unprecedented value of 6.7, which shows the catalyst’s stability against poisoning by carbonaceous intermediates.

Bulk-synthesized silicon carbide, hitherto considered inactive for electrochemical lithium insertion, is demonstrated as a potential high-capacity, long-cycling anode material for lithium-ion batteries. In this study, we show that cubic (3C polytype) nano SiC, prepared by a chemical vapour deposition (CVD) method, delivers a reversible lithium insertion capacity of about 1200 mA h g−1 over 200 cycles.

8 We acticipate that this reaction, while quite useful in its own right, may also be the prototype for other novel transformations based on transition-metal-centered radicals.'* As a first step in this direction we plan to explore intermolecular additions of epoxides to activated olefins. Supplementary Material Available: Details of isolation and characterization (13C NMR, 'H NMR, HRMS, elemental analysis) of products 1-8 (4 pages). Ordering information is given on any current masthead page.