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Water ices at 15 and 144 K were bombarded by swift heavy ions, 45.8 MeV 58Ni11 + and 606 MeV 64Zn26 +, to measure the induced chemical and physical effects. The column densities of water and the synthesized species, hydrogen peroxide (H2O2) and ozone (O3), were monitored via infrared spectroscopy. The formation and destruction cross-sections of precursor and products were determined and compared with literature. The H2O2 formation and destruction cross-sections reveal a linear dependence with electronic stopping power, σ ∝ Se. The sputtering yield (Y0) shows a power law with electronic energy lost, $Y_0\propto S_\mathrm{e}^2$, and an exponential increase with the sample temperature. The findings indicate that the radiolysis rate of water ice is higher at low temperatures while the desorption yield increases at higher temperatures. A large amount of water ice is located in the grain mantles of the circumstellar envelopes and the interstellar medium regions, which are exposed to galactic cosmic rays (GCRs). The synthesis of H2O2 and O3 molecules as a function of absorbed doses of GCR irradiation and their irradiation time is analysed in detail. Besides, the extrapolation of the sputtering yield rates, as a function of time and temperature, for astrophysical conditions can contribute to a better understanding of non-thermal sputtering of water ices.

The interstellar chemistry of nitrogen is considerably less understood than the chemistry of other common elements, such as carbon and oxygen. Even though a relatively large number of species containing nitrogen atoms have already been detected in the interstellar medium, only six of them bear a nitrogen–oxygen (N–O) bond. Some astrophysical and primeval Earth models suggest that N–O species, such as hydroxylamine (NH2OH), are potential precursors of prebiotic amino acids, and even peptides. In this work, we have analyzed an apolar ice mixture of N2:CO of astrophysical interest to investigate possible formation mechanisms of N–O bearing molecules due to processing of the sample by 64Ni24+ 538 MeV ions (8.4 MeV/u) at 14 K. The results show the formation of simple nitrogen oxides ($\rm {N_{1 - 2}}{O_y})$, but no CN–O species of any kind. We have also determined the formation cross-sections of some of the products, as well as the destruction cross-sections of precursors and products. The results presented here are discussed in light of our previous work on the processing of a NH3:CO ice mixture, which have found no N–O bearing molecules at all.

Cost-effective and sustainable high-performance supercapacitor material was successfully prepared from cellulosic waste (Sapindus trifoliatus nut shells) biomass-derived activated carbon (CBAC) by physical activation method. The CBAC displays nanofiber morphology, high specific surface area (786 m2/g), large pore volume (0.212 cm3 g−1) which are evaluated using FESEM, BET and possessed excellent electrochemical behavior analyzed through various electrochemical methods. Moreover, the assembled symmetric CBAC//CBAC device exhibits high specific capacitance of 240.8 F g−1 with current density of 0.2 A g−1 and it is maintained to 65.6 F g−1 at high current density of 2.0 A g−1. In addition, the symmetric device delivers an excellent specific energy maximum of over 30 Wh kg−1 at 400 W kg−1 of specific power and excellent cycling stability in long term over 5000 cycles. The operation of the device was tested by light-emitting diode. Hence, CBAC-based materials pave way for developing large-scale, low-cost materials for energy storage device applications.

Energy crisis and environmental pollution have been one of the major global issues. In this regard, the search for new energy storage materials is cheap, flexible and high-performance supercapacitors electrode which has become intensive. Also, reducing the amount of organic dyes polluting in water is a great significance. Herein, one-step electropolymerization of methylene blue on carbon fiber and the resulting films were applied to the supercapacitor. The high performance is associated to the outstanding conductivity, electrochemical stability and superior mechanical flexibility of carbon fiber. A new flexible electrode for supercapacitors was successfully fabricated by demonstrating with a good electrochemical performance and a promising alternative to reduce the water pollution.

Supercapacitors are considered as one of the most efficient and reliable approaches to fulfill the specifications of the energy storage devices, owing to high-efficiency storage of energy, which makes supercapacitive electrode materials provoke large curiosity. In this work, we report the electropolymerization of poly(p-phenylenediamine) (PpPD) films on lightweight and inexpensive flexible carbon fiber fabrics by potentiostatic technique. The ladder structure of the electrochemically prepared PpPD was examined by Fourier transform infrared spectroscopy (FTIR). The surface characteristics and elemental composition studies were performed through field-emission scanning electron microscope (FESEM) and energy-dispersive X-ray spectroscopy (EDS), which confirmed the polymerization on the carbon fabrics. The electrochemical behavior of the fabricated supercapacitors was investigated by electrochemical analysis including cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The electrodes presented a good capacitive retention in a sweep rate range between 5 and 100 mV s−1 using cyclic voltammetry. The coated electrode exhibited good electrochemical property with a high specific capacitance of 80 F g−1 at the current density of 1 A g−1. The high electrochemical performance is associated to the outstanding conductivity, high electrochemical stability, and superior flexibility of the carbon fiber fabrics. The accomplishment of such superior performance, lightweight, and mechanically flexible supercapacitor can stimulate the use in energy storage applications and wearable electronics.

H2O:CO, at concentrations of (3:2) and (10:1), was condensed on CsI substrate at 15 K and irradiated with 46-MeV 58Ni11 + ion beam. Radiolysis induced by fast heavy ions was analyzed by infrared spectroscopy (FTIR). The formation of nine molecular species: CO2, H2O2, HCOOH, HCO, H2CO, 13CO2, CH3OH, O3, and C3O2 was observed. For both concentrations, carbon dioxide (CO2), formaldehyde (H2CO), formic acid (HCOOH), and hydrogen peroxide (H2O2) are the most abundant products species, and tricarbon dioxide (C3O2) is much less abundant. Precursor destruction cross-sections and formation cross-sections of products are determined. The CO destruction cross-section for the (3:2) concentration is almost five times higher than that of water, while those for the (10:1) concentration are practically the same. Atomic sputtering yields are estimated for the two ice films, the total mass sputtered is approximately 2.5 × 106 u per impact. These results contribute to figure out the chemical pathways of compounds synthesized from the two most abundant organic species (H2O and CO) observed in the ices of grain mantles of the circumstellar envelopes and interstellar medium. In additional, the finding results reveal that molecular astronomical percentages are comparable to those obtained after 15 eV molec−1 of deposited dose in current experiments compared with the relative concentration of molecules in solid phase observed in MYSO, LYSO, BG Stars, and Comets.

H2O and CO molecules are the main constituents of the interstellar dust grain ice mantles. Infrared spectra of the ices in line of sights of young stellar objects and background stars have shown that the CO stretching vibration band can be decomposed into three main components: 2143, 2139 and 2136 cm−1, assigned to CO in different environment sites. The relative strengths between the components have been associated to an evolutionary track of the interstellar molecular clouds. H2O:CO (3:2) and (10:1) ices samples were irradiated by 0.79 MeV/u 58Ni13 + ions to simulate the effects produced by heavy ion cosmic rays in typical interstellar ices mixtures. The CO stretching vibration band is decomposed into six Gaussians functions (2150, 2144, 2141, 2138, 2136 and 2133 cm−1) and their integrated absorbances were measured as a function of fluence. The results have shown that, at the final fluence, the component 2138 cm−1 is the main component of the CO stretching vibration band. The component 2150 cm−1 disappears at the beginning of irradiation. Based on the present and previous results, a time scale for the components in the interstellar ices is proposed. For H2O:CO ice in the ISM it is predicted that, after 1 Myrs, the main components of the CO stretching vibration band are the 2138 cm−1 and 2141 cm−1, due to the CO monomers and dimers, respectively.

International audience; N2O and CO2 can be formed in the interstellar space and in ices on the surface of outer solar system bodies, such as Pluto and Triton. Energetic ions can simulate the energy transfer processes that occur by cosmic ray irradiation of interstellar ices, comets, and icy solar system bodies. Proceeding systematic research, pure nitrous oxide (N2O) ice, and nitrous oxide and carbon dioxide (CO2) ice mixture were irradiated at 11 K with MeV-nitrogen (N+) and -xenon (Xe23+) ion beams. The chemical and physical effects induced by ion irradiation on the N2O ice and the N2O:CO2 ice mixture are compared. The formation and dissociation cross sections scale with the electronic stopping power (Se) roughly as σ ∼ a Sen, where n ∼ 3/2. The n power law is helpful for predicting the N2O formation and dissociation cross-sections for other ion beam projectiles and energies; these predictions will allow estimating the effects of the entire cosmic ray radiation field.

This paper reports the fabrication of an ultra-high energy and power density asymmetric supercapacitor (ASC) containing a novel porous carbon nanofiber derived from hypercross-linked polymers (HCP-CNF) and two-dimensional copper cobalt oxide nanosheets (CCO-NS) as the negative and positive electrodes, respectively. The micropore-enriched HCP-CNF is obtained from a facile Friedel-Crafts reaction with naphthalene and α, α′-dichloro-p-xylene as the starting material. The CCO-NS have been prepared by a simple and inexpensive hydrothermal synthesis using polyvinylpyrrolidone (PVP) as a shape controlling agent. The fabricated CCO-NS//HCP-CNF ASC device exhibit a high specific capacitance, 244 F g−1 at a current density of 1 A g−1, owing to the unique porous architecture of CCO-NS and the interconnected microporous carbon skeleton with a high surface area of HCP-CNF. Furthermore, the assembled ASC device show an ultra-high energy density of 25.1 Wh kg−1 at a power density of 400 W kg−1 with maximum operating voltage of 1.60 V. The electrode shows good capacitance retention (91.1%) after 5000 cycles in a 3 M aqueous KOH solution. In addition, two ASC devices are connected in series powered a 5 mm diameter LED indicator for approximately 30 min, highlighting its efficient power supply.

A biocompatible dicalcium phosphate dihydrate (DCPD) brushite coating of flake-like crystals was developed on AZ91D and AZ31 magnesium (Mg) surfaces to control and slow down the rapid degradation rate of the substrates. The electrochemical behavior of the DCPD-coated substrates was examined in a simulated body fluid (SBF) with uncoated substrates as the control. Fabrication of the coating was achieved via chemical immersion technique by modifying the surfaces with Ca(NO3)2·4H2O and KH2PO4 in addition to heat treatment. The morphology of the DCPD coating is uniform and dense with a flake-like crystal structure. After in vitro tests, the DCPD coating would have exhibited excellent corrosion resistance with more biomineralization of the active calcium phosphate (CaP). Moreover, the DCPD coating induced CaP formation after immersion in the SBF, indicating excellent bioactivity upon increasing the coating. Hence, the two-step chemical treatment enhances the bioactivity of DCPD coatings on Mg alloys, making them better implant materials.

Highly ordered mesoporous carbon (OMC) is an attractive material that can be exploited in electrochemistry owing to its chemical inertness, highly specific surface area, excellent conductivity of electrons, well-ordered pore structure and tuneable pore diameters (uniform pore volume and size) in the mesopores range. Herein, we review the recent utilization of an OMC-based disposable electrode material, which has been devoted to electrochemical sensors and biosensors fabrication. The well-ordered mesostructure of three-dimensional mesoporous carbon is essential in those applications. OMC offers numerous favourable active sites for transferring electrons to sensing the analytes due to its characteristics, such as large surface area, oxygen-containing functional groups and numerous edge plane-like defective sites, which makes OMC a prospective material for the examination of the electrocatalytic behaviour of various analytes. Nowadays, the number of research related to OMC-based disposable sensors is increasing because of their excellent physicochemical properties. This chapter details recent developments on the design and fabrication of OMC related materials that are used for modified electrodes in disposable sensors. The chapter provides a basic understanding of the synthesis methods, a description of the structural properties and electrochemical performances and applications towards sensing and biosensing.

Dye-sensitized solar cells, termed as DSSC’s have been gaining interest from researchers and industry in the last few years. Such an interest derives from their low-cost manufacturing and easy processing to replace conventional silicon cells. A DSSC operating system consists of three steps: a photoelectrode (anode), an electrolyte solution and a counter electrode (cathode). The dyes aims to expand the absorption band of the device. The most popular dyes are those containing anthocyanins that exist in leaves, fruits, roots, among others. Two photosensitizing natural dyes are proposed in this paper: a passion fruit (Passi-flora eduris) and green coconut (Cocos n ucifera). Measurements such as structural and morphological, optical characterization and electrochemical analyzes of the photoelectrode coated with TiO 2 and platinum were performed. The photo-voltaic efficient performance were measured and compared with the literature. The electrolytic solution made in laboratory fulfilled its function, regenerating the dye with ions. The results showed that Passiflora eduris dye showed the best efficiency 0.52% compared to other types of fruits in the literature. The results reveal that both present good performance for DSSC’s manufacturing.

Among the existing energy storage devices, supercapacitors have attracted an increasing attention in recent years. In this work, two different transition metal (M = Cu, Co) oxides grafted on graphitic carbon nitride (GCN) nanosheets were successfully synthesized through single-step pyrolysis assisted route. The as-prepared nanocomposites exhibit high specific surface area and demonstrate the excellent electrochemical performances for supercapacitors. The CoO/GCN-NS and CuO/GCN-NS electrodes facilitate rapid Faradaic reaction in aqueous 6.0 M KOH electrolyte, and deliver the highest specific capacitance of 458 F g-1 and 154.5 F g-1 at 0.5 A g-1. The CoO/GCN-NS and CuO/GCN-NS electrodes were integrated with commercial activated carbon (AC) to fabricate asymmetric supercapacitors, which exhibits high specific capacitance of 124.75 F g-1 (CoO/GCN-NS//AC) and 84.28 F g-1 (CuO/GCN-NS//AC) at 0.5 A g-1 and higher cycling performance (about 96% retention after 2000 cycles). An asymmetric supercapacitor device could power a light emitting diode (LED), demonstrating that metal oxide/GCN-NS is a potential electrode material for energy storage applications.

Sonoluminescence (SL) is a physicochemical phenomenon that is observed when a single or multiple air bubbles, excited by an acoustic field in water, collapse and emit light. Until nowadays, it is still an outstanding phenomenon in which acoustic energy is (partially) transformed into light. Along the years, some models have been proposed to explain sonoluminescence and a lot of experimental setups have been built in an attempt to reproduce and study it. Since the flash of light is forced to occur inside a resonant cavity (i.e., a glass flask filled with water) by using external circuitry, many efforts have been made to study the relationship between the phenomenon and the electrical and mechanical quantities involved in the experimental apparatus. Following this field of study, this paper proposes an electronic instrumentation system based on a FPGA device for performing automatic monitoring of the input signal applied to the resonator as well as the output response signal produced by it. The objective of using the automated setup is to collect data for characterizing the resonator frequency response in order to identify its input/output behavior. The key idea is to find out whether there is a linear circuit which might have analogous input/output characteristics that may be used to simulate the phenomenon in future studies.

Dye-sensitized solar cells (DSSCs) have been considered as an alternative energy resource in recent years, due to low-cost fabrication and non-toxic compared to silicon-based and thin film solar cells. Herein, the natural dye containing anthocyanins were extracted from Thunbergia erecta natural flower petals by simple extraction techniques and used as photosensitizers in the DSSC. The extracts showed the UV–Vis absorptions in the 400–800 nm range with broad maxima in visible region around 537 nm. Fourier transform infrared (FTIR) spectrum was obtained after the dye coating on a semi-conductive layer, to identify the presence of anthocyanin according to the functional groups present in the dye molecules. To precise and progressive optimization of the TiO2 photoanodes film thicknesses were prepared by spin coating technique and characterized by atomic force microscopy, field emission scanning electron microscopy and J-V characteristics. The photovoltaic performance studies were carried out to understand the effect of the TiO2 multilayer photoanodes and the interaction with the dye molecules on the cells efficiency. Photovoltaic parameters like short circuit current (JSC), open circuit voltage (VOC) and fill factor (FF) were evaluated for fabricated cells. The optimized film thickness of the TiO2 photoanode is ∼5.5 μm with an efficiency of 0.37% under AM 1.5G illumination of sunlight. The VOC of DSSCs gradually decreases as the thickness increases of the TiO2 thin film and the highest conversion efficiency while it has the maximum short-circuit current density.

Solar power is a renewable and promising solution to the today’s world energy needs. Recently, researchers in finding an alternative energy resource for the next generation lead to the production of efficient photovoltaic cells. Herein, dye-sensitized solar cells (DSSCs) containing semiconducting nanostructured TiO2 thin film photoanodes were fabricated by spin-coating technique, using a self-constructed spin coater, which is a simple and cost-effective method. The composition and superficial characteristics of the films were studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier transform infrared spectroscopy (FTIR). Microscopic analysis revealed the electrode surface morphology, and microstructure were influenced by spin-coating technique compared to doctor blade method. The natural dyes of anthocyanin were extracted from jabuticaba (Plinia cauliflora) fruit using a simple extraction technique, used as photosensitizers in DSSCs and their characteristics were studied. The extracts showed the UV–Vis absorptions in the 450–600 nm range with broad maxima at ~ 545 nm. FTIR showed the presence of anthocyanin in the dye molecules of jabuticaba fruit, which can be related to a better photon to electron conversion. The photoelectrochemical performance and the efficiency of assembled DSSCs using jabuticaba fruit dye extract were evaluated, and efficiency enhancement was obtained by spin-coated TiO2 electrodes. The efficiency and fill factor of the DSSC using jabuticaba fruit dye were 0.13% and 0.29%, respectively. The results successfully showed that the DSSC, using jabuticaba fruit extract as a dye photosensitizer, is valuable for the preparation of eco-friendly, less-expensive, renewable, and clean sources of energy.

Undoped and gadolinium doped nanostructured mesoporous materials, such as NiO, Ni0.98Gd0.02O, Ni0.95Gd0.05O, and Ni0.92Gd0.08O, were synthesized by a facile hydrothermal route using urea as the hydrolysis controlling agent and were studied for supercapacitor applications. The thermal stability of the synthesized samples was identified by thermogravimetric analysis. The phase structure of the as-synthesized and calcined materials was characterized by using powder X-ray diffraction. The average crystallite size of the oxide materials was found to be in the range of 8.2–11.3 nm. Fourier transform infrared spectroscopy revealed the metal–oxygen bond in the compounds. The analyzed morphological phenomenon of the prepared samples confirms the mesoporous flake-like shape. The N2 adsorption/desorption isotherms were performed to examine the surface area and pore-size distribution. The elemental composition and charge states analyses were obtained by energy-dispersive X-ray and X-ray photoelectron spectroscopy, re...

Protecting the surface of metals and alloys against corrosion and wear is of abundant importance owing to their widespread applications. In the present work, we report the improved anticorrosion and tribo-mechanical performance of copper (Cu) by a hard carbon (HC) coating synthesized in different pyrolysis temperature. Structural and surface characterization with roughness measurements was systematically investigated using various techniques. Effect of pyrolysis temperature on the corrosion behavior of coated Cu substrates in 0.6 M NaCl solution was evaluated via electrochemical impedance spectroscopy, potentiodynamic polarization. Pin-on-disk wear test of coated Cu substrate showed the influence of the pyrolysis temperature on the wear resistance performance of the HC coatings. According to the obtained results, it could be concluded that the HC coatings synthesized at 1100 °C revealed an enhanced comprehensive performance, revealing their possible utilization as a protective coating for Cu substrates in chloride environment. Monte Carlo simulations have been utilized to elucidate the interaction between the Cu surface and HC coatings.

A facile approach based on electrochemical polymerization was used to synthesize polypyrrole/CeO 2 (PPy/CeO 2 ) nanocomposite on an AA2024 alloy surface. CeO 2 nanoparticles (NPs) embedded in the PPy matrix were observed using FESEM micrographs with EDX analysis. IR and UV–vis spectroscopy were used to characterize the synthesized PPy/CeO 2 nanocomposite. The Raman spectra reflected the interactions between the π-conjugated structure of PPy and CeO 2 NPs. TGA thermograms revealed improved thermal stability of the synthesized nanocomposite and were used to determine the amount of nano ceria incorporated in the PPy matrix. The electrochemical corrosion behavior of the coated alloys in 0.6 M NaCl solution was examined through potentiodynamic polarization and electrochemical impedance spectroscopic (EIS) measurements. From these electrochemical studies, a larger shift of E corr in the positive direction with a high amount of CeO 2 in the nanocomposite was obtained, as well as a maximum corrosion protection efficiency of 99.64% by incorporating 3% of CeO 2 NPs in the PPy coatings. EIS studies also confirmed the enhanced corrosion protection behavior of PPy/CeO 2 coatings with higher R ct , R f and lower CPE dl values compared to those of pure PPy coatings. The results showed that the PPy coatings with CeO 2 nanoparticles can be potential coating materials for the corrosion protection of AA2024 alloys substrates.

Improvement of the electrical conductivity, specific capacitance and binder-free polyaniline (PANI) interconnected with metal(II) hexacyanoferrate(III) (MHCF) nanocomposites (M = Ni, Co) on flexible carbon fibers (CF) were designed in our present research goal. PANI/MHCF/CF nanocomposites were prepared by one-step co-polymerization method. Electrochemical studies like cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy were analyzed. Under the optimized conditions, the nanocomposites demonstrated remarkable electrochemical performances as supercapacitor electrode with outstanding specific capacitances of ~725 F g−1 at a current density of 1 A g−1, and retained ~325 F g−1 even at a high current density of 20 A g−1 in 0.5 M H2SO4 + 0.5 M Na2SO4 solution. The excellent cycling stability with capacitance retention of 80% after 1000 cycles may be a potential electrode material for future supercapacitor when its cycling stability and rate performance are addressed.

)3 Acetylene, C2H2, has been observed in the interstellar medium, mostly around young stellar objects, as well as in molecular clouds and cometary comae, representing an important species of astrophysical interest. In this work, we present a laboratory study of the C2H2 radiolysis at 45 K for three different beams and energies: 1.0 MeV H+ and He+, and 1.0 and 1.5 MeV N+ beams. Fourier transform infrared spectroscopy was used for monitoring the molecular changes induced by the ion processing. Two different sample thicknesses were irradiated; for the thicker one, implantation had occurred. Spectra and absorbance evolutions for the thin and thick films are qualitatively different. Four C2H2 bands are observed at 3225, 1954, 1392, and 763 cm−1. The C2H2 compaction and apparent destruction cross-sections are determined. For the case of the H+ beam, the compaction cross-section dominates. Concerning molecular synthesis by irradiation, New product bands were not observed in the thin ice irradiations; for the thicker film ice, the daughter species CH4, C2H4, C3H6, and C4H4 have been identified and their destruction and formation cross-sections determined. The apparent destruction cross-section was found to be a function of the electronic stopping power (Se) as σd ∝ S$_\mathrm{ e}^{3/2}$. The half-life of the C2H2 bombarded by galactic cosmic rays is estimated. The current findings are a contribution to the understanding of how the molecules synthesized upon irradiation of Interstellar and outer Solar system ices participate to the molecular enrichment and to the physicochemical evolution of the Universe.

Experimental results on the processing of NH3:CO ice mixtures of astrophysical relevance by energetic (538 MeV 64Ni24+) projectiles are presented. NH3 and CO are two molecules relatively common in interstellar medium and Solar system; they may be precursors of amino acids. 64Ni ions may be considered as representative of heavy cosmic ray analogues. Laboratory data were collected using mid-infrared Fourier transform spectroscopy and revealed the formation of ammonium cation (NH$_4^+$), cyanate (OCN−), molecular nitrogen (N2), and CO2. Tentative assignments of carbamic acid (NH2COOH), formate ion (HCOO−), zwitterionic glycine (NH$_3^+$CH2COO−), and ammonium carbamate (NH$_4^+$NH2COO−) are proposed. Despite the confirmation on the synthesis of several complex species bearing C, H, O, and N atoms, no N–O-bearing species was detected. Moreover, parameters relevant for computational astrophysics, such as destruction and formation cross-sections, are determined for the precursor and the main detected species. Those values scale with the electronic stopping power (Se) roughly as σ ∼ a S$_\mathrm{ e}^n$, where n ∼ 3/2. The power law is helpful for predicting the CO and NH3 dissociation and CO2 formation cross-sections for other ions and energies; these predictions allow estimating the effects of the entire cosmic ray radiation field.

In this work, the natural flower extracted dyes containing luteolin were prepared using three different specimens from daisy flowers family (Leucanthemum vulgare), namely yellow daisy, purple daisy and wine daisy, according to the color of its petals. Moreover, DSSCs were fabricated using nanosized titanium dioxide (TiO2) as an anode; for the photocathodes, two different specimens were used: i) graphite electrode and ii) platinum electrode. To recognize the light absorption behavior, the existence of anchoring groups and coloring components of the extracted dyes were determined using absorption spectroscopy. The surface roughness of the photoanodes and cathodes were examined using atomic force microscope (AFM). The photovoltaic performance and efficiency of assembled DSSCs were evaluated to realize the influence of TiO2 photoanodes on interaction of the Leucanthemum vulgare extracted dye molecules with graphite or platinum photocathodes. DSSCs fabricated with platinum cathode show higher conversion efficiency (η) of 0.6%, 0.4% and 0.8% for the yellow daisy, wine daisy and purple daisy, respectively. DSSCs sensitized with daisy wine dye showed highest open-circuit voltage (Voc) of 520 mV and efficiency of 0.79% and 0.88%, for the graphite and platinum cathodes, respectively. These results showed that the DSSCs, using daisy flowers extracts as efficient photosensitizers, are suitable for the fabrication of environmentally safe, inexpensive, clean and renewable energy.

There is increasing demand for highly stable and solid-state dye-sensitized solar cells (DSSCs) for renewable energy resources. Following this concern, we have fabricated DSSCs using different thicknesses thin films of TiO2 photo-anode, graphite film as cathode and extracted natural dyes from fruits and vegetables as sensitizers. The effect of natural dye molecules on TiO2 particles and photon–electron conversion efficiencies were studied. Microstructures of photo-anodes, cathodes and the functional groups of the extracted dye molecules and their conjunction with TiO2 films were analyzed using scanning electron microscopy, atomic force microscopy and Fourier transform infrared spectroscopy, respectively. A mixture of polyvinylpyrrolidone and iodine has been used to prepare a polymer-gel electrolyte, and it confirms the promising behavior of highly stable and solid-state DSSCs. Amongst a variety of natural dyes extracted from fruits, jabuticaba skin dye shows better performance of the DSSCs in this work. The obtained results show that the thickness of the photo-anode thin film influences directly on the photovoltaic performance.

Synthesis of biomass derived microporous activated carbon materials has fascinated attention in the emerging field of energy storage due to its high specific surface area, excellent electrical conductivity, low cost and environmental benevolence. Herein, we report facile and cost-effective method to produce porous activated carbons for the first time by physical activation method using two different biomass sources Syzygium cumini fruit shells (SCFS) and Chrysopogon zizanioides roots (CZR) for fabrication of symmetric supercapacitors. Biomass-derived activated carbon (BAC) materials were obtained via a two-step synthesis: (i) carbonization at 700 °C in N2 atmosphere (ii) CO2 activation at 700 °C in N2 atmosphere. The formation of high surface area and disordered micropores on the carbon by CO2 activation was identified by N2 adsorption-desorption and FE-SEM techniques. SCFS-AC and CZR-AC exhibit enhanced electrochemical performances in three-electrode configuration showing their high specific capacitances with good capacitance retention. These biomass derived activated carbon (BAC) based symmetric supercapacitors deliver energy density maximum of 27.22 W h kg−1 (SCFS-AC) and 16.72 W h kg−1 (CZR-AC) at 200 W kg−1 power density with an outstanding cycling stability over 5000 cycles. This work offers an environmentally safe and innovative approach to control the porosity in BAC for energy storage applications.

International audience; Physico-chemical modifications induced by swift heavy ions on methane-water (CH 4 :H 2 O) ices at 15 K are analyzed. Ice films, at concentrations of (1:3) and (1:15), were irradiated by 40 MeV 58 Ni 11+ ions. Fourier transform transmission spectroscopy in the mid-range was used to monitor the evolution ices at 15 K as a function of projectile fluence. New IR bands appearing for the irradiated (CH 4 :H 2 O) (1:3) ice are attributed to the synthesized molecules: C 3 H 8 , HCO, H 2 CO, CO, CO 2 , H 2 O 2 , HCOOH, CH 3 OH, C 2 H 5 OH, and CH 3 CHO. For the irradiated (CH 4 :H 2 O) (1:15) ice, the abundances of the compounds containing two carbons atoms are lower than those for the (1:3) ice; in contrast, CH 3 OH and H 2 O 2 abundances increase when compared to the values obtained with the (1:3) ice. After irradiation, the ices were warmed up until 110 K, when the IR spectra reveal features of complex organic molecules. The destruction and formation cross sections and the sputtering yields of the ice mixtures are estimated. These findings provide possible pathways for the occurrence of compounds rich in C, O, and H, which are indeed observed in the cold regions of the universe such as ices in grain mantles of the interstellar medium and circumstellar envelopes.

Nitrogen rich porous carbon balls are derived from hypercross-linked polymers (HCPs) of anthracene and subsequent carbonization with urea. The obtained materials exhibit combination of abundant microporous and minimal mesoporous property with large surface area (623.27 to 928.44 m2 g − 1). The influence of annealing temperature in nitrogen doped porous HCPs was examined the capacitive performance of the prepared electrode materials using electrochemical techniques. A symmetric device was assembled, and it shows a high specific capacitance of 206.4 F g − 1 at 0.2 A g − 1 with excellent rate capability. Also, the material exhibits excellent durability only 3.5% loss was observed after 5000 cycles (capacitance retention of 96.5%). These outcomes justify that nitrogen anchored porous carbon balls are excellent materials for high-performance symmetric supercapacitors.

Astronomical observations towards star-forming regions have revealed the presence of molecules with the N-O bond such as NO, N2O, and HNO. These species are considered potential precursors of prebiotic molecules. Thus, understanding nitrogen and oxygen chemistry may help us to better understand the origin and evolution of prebiotic molecules in space. However, species with the N-O bond are poorly studied and laboratory works on the effects induced on them by solar wind and galactic cosmic rays are still scarce. For this, we wanted to study the effects of ion bombardment on molecules with the N-O bond. We focus here on N2O ices and NO2:N2O4 = 1:1 ice mixtures (at 16 and 50/60 K) irradiated with 200 keV protons. Infrared transmission spectroscopy (8000-500 cm-1; 1.25-20 μm) was used to analyse the samples. Irradiation of N2O ices and NO2:N2O4 ice mixtures produces comparable effects independent of the irradiation temperature, NO being the main product. Moreover, we show that the maximum amount of N2O and N2O4 destroyed by irradiation, at the highest dose reached in our experiments, is equal to about 98 and 70 {{ per cent}}, respectively. The dose range covered in the experiments has been compared with the astrophysical time-scale of surface processing in space, showing that irradiation of N2O and NO2:N2O4 mixtures can produce, within 105-108 yr, amounts of solid NO ice detectable towards star-forming regions by the James Webb Space Telescope.

The matrix-isolated mid-IR (MIR) spectrum of neutral and ionized anthracoronene (C(36)H(18), AnthCor) in argon has been measured experimentally, compared to the spectrum of its parent molecules, coronene and anthracene, and analyzed by comparison to a theoretical spectrum computed using density functional theory (DFT). The experimental and theoretical band positions generally agree within 0–10 cm(−1). Anthracoronene exhibits extremely intense cation and anion bands around 1330 and 1318 cm(−1). The intensity of these two bands approaches what is traditionally observed in the entire 1000–1600 cm(−1) range for a typical PAH cation or anion. The matrix-isolated Near-IR (NIR) through Overlap Region (OVR) spectrum of ionized AnthCor in argon has been reported for the first time and compared to the spectrum of its parent molecules, coronene and anthracene. AnthCor cation contains a very strong electronic transition around 6175 cm(−1), placing it outside the range of the electronic transitions typically observed for PAHs. Anthracoronene is one of the few PAHs studied to-date which has exhibited the formation of anions upon UV photolysis.

A connection between the compaction of amorphous solid water (ASW) during energetic ion irradiation and the disappearing of water dangling bonds (OH-db) has been analyzed particularly by the Palumbo et al. and by Baragiola et al. In this work, a further discussion of the process for inducing the compaction is presented. Simple models for OH-db evolution for irradiated water ice are discussed. Literature results on the OH-db disappearance in ices bombarded by 100–200 keV H+ ions and on the comparison of porosity and OH-db results for 200 keV Ar+ ions are revisited. It is observed that for both, porosity decrease (compaction) and OH-db absorption signal decrease, experimental data can be well fitted by the sum of two decreasing exponentials with similar sets of parameters. Although a clear explanation for this correlation cannot be extracted, it suggests strongly that compaction and OH-db destruction are both triggered by two different processes.

Dicalcium phosphate dihydrate (DCPD) brushite coating with flake like crystal structure for the protection of AZX310 and AM50 magnesium (Mg) alloys was prepared through chemical deposition treatment. Chemical deposition treatment was employed using Ca(NO3)2·4H2O and KH2PO4 along with subsequent heat treatment. The morphological results revealed that the brushite coating with dense and uniform structures was successfully deposited on the surface of AZX310 and AM50 alloys. The X-ray diffraction (XRD) patterns and Attenuated total reflectance infrared (ATR-IR) spectrum also revealed the confirmation of DCPD layer formation. Hydrophilic nature of the DCPD coatings was confirmed by Contact angle (CA) measurements. Moreover, electrochemical immersion and in vitro studies were evaluated to measure the corrosion performance and biocompatibility performance. The deposition of DCPD coating for HTI AM50 enables a tenfold increase in the corrosion resistance compared with AZX310. Hence the ability to offer such significant improvement in corrosion resistance for HTI AM50 was coupled with more bioactive nature of the DCPD coating is a viable approach for the development of Mg-based degradable implant materials.

International audience

International audience

Electronic sputtering of organic species being mixed to water ice by residual-gas condensation is analyzed by secondary ion time-of-flight mass spectrometry. The ice samples were prepared at 15 K by deposition from a H2O gas-flow and irradiated by 1.5 MeV N2+ ions while the temperature was raised up to 216 K. Desorption ion yields of positive H2O specific ions as of some organic ion species are measured as a function of temperature. Remarkably high desorption yield variations, mainly of the CnHm ions, were observed during the enrichment of organics hiding the emission of (H2O)nH3O+ cluster ions.

Methane (CH4) ice is found in the interstellar medium and in several bodies of the Solar system, where it is commonly exposed to cosmic rays and stellar winds. The chemical, physical and structural effects induced by fast heavy ions in thin layers of pure CH4 ices at 15 K are analysed by mid-infrared spectroscopy (Fourier transform infrared). Different pure CH4 ice samples were irradiated with 6 MeV 16 O 2 + , 220 MeV 16 O 7 + , 267 MeV 56 Fe 22 + and 606 MeV 70 Zn 26 + ions at Grand Acc´´ National d’Ions Lourds/France. Results show that CnHm molecules, where n = 2–4 and m = 2(n − 1) to 2(n + 1) and radical species CH3 ,C 2H3 and C2H5 are formed. The destruction cross-sections of CH4 ice and the formation cross-sections of new molecules CnHm are reported. The extrapolation of current results allow us to estimate the half lives of CH4 ices in the interstellar medium and the Solar system (Earth orbit) as about 600 × 10 6 and 600 yr, respectively. This huge ratio strongly suggests that the vast majority of

Sonoluminescence (SL) is the phenomenon in which acoustic energy is (partially) transformed into light. It may occur by means of many or just one bubble of gas inside a liquid medium, giving rise to the terms multi-bubble- and single-bubble sonoluminescence (MBSL and SBSL). In the last years some models have been proposed to explain this phenomenon, but there is still no complete theory for the light emission mechanism (especially in the case of SBSL). In this work, we will not address this more complicated particular issue, but only present a simple model describing the dynamical behaviour of the sonoluminescent bubble, in the SBSL case. Using simple numerical techniques within the software Matlab, we discuss solutions considering various possibilities for some of the parameters involved: liquid compressibility, superficial tension, viscosity, and type of gas. The model may be used as an introductory study of sonoluminescence in physics courses at undergraduate or graduate levels, as well as a quite clarifying example of a physical system exhibiting large nonlinearity., 10 pages, 5 figures. European Journal of Physics (2013)

The radiolysis of a nitrogen-acetone mixture, condensed at 11 K, by 40 MeV $^{58}$Ni$^{11+}$ ions is studied. These results are representative of studies concerning solar system objects exposed to cosmic rays. In the Kuiper Belt, region of Trans-Neptunian Objects (TNOs), acetone, molecular nitrogen and other small molecules were detected and may be present on icy surfaces. Bombardment by cosmic rays triggers chemical reactions leading to synthesis of larger molecules. In this work, destruction cross sections of acetone and nitrogen in solid phase are determined from a sequence of infrared spectra obtained at increasing ion beam fluence. The results are analyzed and compared with those of previous experiments performed with pure acetone. It is observed that the molecular nitrogen column density decrease very fast, suggesting that nitrogen quickly leaves a porous sample under irradiation. The behavior of acetone in the mixture confirms that the ice formed by deposition of vapor mixture is more porous than that of pure acetone ice. The most abundant molecular species formed from the mixture during irradiation are: C$_3$H$_6$, C$_2$H$_6$, N$_3$, CO, CH$_4$ and CO$_2$. Some N-bearing species are also formed, but with low production yield. Comparing with pure acetone results, it is seen that dissolving acetone in nitrogen affects the formation cross sections of the new species: CH$_4$, CO$_2$ and H$_2$CO, for example, have formation cross section smaller than the respective values for irradiated pure acetone, while those for CO and C$_2$H$_6$ species are higher. This fact can explain the presence of C$_2$H$_6$ even in regions on Pluto where CH$_4$ is not pure, but diluted in a N$_2$ matrix together with less abundant species. These results also show the formation of more complex molecules, such as HNCO, acetic acid and, possibility, glycine., Comment: 16 pages, 9 figures, 5 tables

International audience; The radiolysis of pure N2O ice at 11 and 75 K by 90 MeV 136Xe23 + ion irradiation has been studied by Fourier-transformed infrared spectroscopy (FTIR). Six daughter molecular species have been observed: NO2, (NO)2, N2O3, N2O4, N2O5, and O3. The chemical evolution of the new molecules formed in the sample was followed by the measurement of the column densities of the precursor and products as a function of the beam fluence. This procedure allows the determination of their formation and dissociation cross-sections. Other processes monitored by FTIR were sublimation (non-existent at 11 K, but present at 75 K) and ice compaction by the ion beam. Comparison between results obtained for the 11 and 75 K ices shows that formation and destruction cross-sections are higher (for light products) or much higher (for heavy products) at 75 K. This enhancement of chemical activity at higher temperature should not be attributed to higher projectile ionization rate but rather to a higher mobility of the radiolysis products in an ice undergoing slow sublimation. Although N2O ice has not yet been observed in space, it is reasonable to expect its occurrence since N and O are very abundant and reactive. Furthermore, if this ice is actually absent, the knowledge of the chemical–physical processes induced by ion irradiation on N2O ice at low temperature is necessary to explain its depletion.

In dense and cold regions of the interstellar medium (ISM), molecules may be adsorbed onto dust grains to form the ice mantles. Once formed, they can be processed by ionizing radiation coming from stellar or interstellar medium leading to formation of several new molecules in the ice. Among the different kind of ionizing radiation, cosmic rays play an important role in the solid-phase chemistry because of the large amount of energy deposited in the ices. The physicochemical changes induced by the energetic processing of astrophysical ices are recorded in a intrinsic parameter of the matter called complex refractive index (CRI). In this paper, we present for the first time a catalogue containing 39 complex refractive indices (n, k) in the infrared from 2.0 - 16.6 micrometer for 13 different water-containing ices processed in laboratory by cosmic ray analogs. The calculation was done by using the NKABS (acronym of determination of N and K from ABSorbance data) code, which employs the Lambert-Beer and Kramers-Kronig equations to calculate the values of n and k. The results are also available at the website: http://www1.univap.br/gaa/nkabs-database/data.htm. As test case, a H2O:NH3:CO2:CH4 ice was employed in a radiative transfer simulation of a prototoplanetary disk to show that these data are indispensable to reproduce the spectrum of YSOs containing ices.

The S2p, S2s, C1s, and O1s Total Ion Yield (TIY) spectra of gaseous dimethyl sulfoxide (DMSO) and the C1s and O1s TIY spectra of acetone were measured using tunable synchrotron radiation. To establish a complete and accurate spectral analysis, the assignments for the main experimental bands were carried out using density functional theory (DFT) calculations based on half core hole (HCH) method, as implemented in the StoBe-deMon program, and ab initio calculations, based on the improved virtual orbital (IVO) method, as implemented in the GSCF3 program, using Hartree-Fock. The hole state was calculated in Huzinaga basis sets for the IVO method and IGLO-III basis sets for the HCH method. A nonlocal BE88-PD86 DFT method was used. The geometric parameters were calculated using the DFT-B3LYP method with the 6-311+G** basis sets. The experimental and theoretical results for the ionization potentials and the threshold energies are quite similar. The results reflect some differences for both molecules, likely caused by the presence of the S=O (Cs symmetry) as well as the C=O (C2v symmetry) groups. © 2012 Wiley Periodicals, Inc.