Hydrogen Ion Exchange Research Articles

A Kinetic-magnetohydrodynamic Model with Adaptive Mesh Refinement for Modeling Heliosphere Neutral-plasma Interaction

The charge exchange between the interstellar medium and the solar wind plasma is crucial for determining the structures of the heliosphere. Since both the neutral-ion and neutral–neutral collision mean free paths are either comparable to or larger than the size of the heliosphere, the neutral phase space distribution can deviate far away from the Maxwellian distribution. A kinetic description for the neutrals is crucial for accurately modeling the heliosphere. It is computationally challenging to run three-dimensional time-dependent kinetic simulations due to the large number of macroparticles. In this paper, we present the new highly efficient Solar Wind with Hydrogen Ion Exchange and Large-scale Dynamics-2 model with a kinetic model of neutrals and a magnetohydrodynamic model for the ions and electrons. To improve the simulation efficiency, we implement adaptive mesh refinement and particle splitting and merging algorithms for the neutral particles to reduce the particle number that is required for an accurate simulation. We present several tests to verify and demonstrate the capabilities of the model.

Evaluating E. coli genome-scale metabolic model accuracy with high-throughput mutant fitness data.

The Escherichia coli genome-scale metabolic model (GEM) is an exemplar systems biology model for the simulation of cellular metabolism. Experimental validation of model predictions is essential to pinpoint uncertainty and ensure continued development of accurate models. Here, we quantified the accuracy of four subsequent E. coli GEMs using published mutant fitness data across thousands of genes and 25 different carbon sources. This evaluation demonstrated the utility of the area under a precision-recall curve relative to alternative accuracy metrics. An analysis of errors in the latest (iML1515) model identified several vitamins/cofactors that are likely available to mutants despite being absent from the experimental growth medium and highlighted isoenzyme gene-protein-reaction mapping as a key source of inaccurate predictions. A machine learning approach further identified metabolic fluxes through hydrogen ion exchange and specific central metabolism branch points as important determinants of model accuracy. This work outlines improved practices for the assessment of GEM accuracy with high-throughput mutant fitness data and highlights promising areas for future model refinement in E. coli and beyond.

Enhancement of microbial fuel cell performance by introducing dosing materials in waste water to increase microorganism growth

This study uses the microbial electrochemical process to produce energy from wastewater. The bacterial growth in sewage has been controlled by applying molasses, vegetables and waste coffee as dosing materials. High-conductive silver metal has been used as an anode, whereas graphite has been used as a cathode. An agar salt membrane has been used as a separator to ensure high hydrogen-ion exchange. During bacterial culture, it is revealed that 21,600,000 cfu/ml, 14,800,000 cfu/ml, and 38,700,000 cfu/ml number of bacteria is observed for molasses, vegetable protein and waste coffee, respectively. In each dosing, E.coli, S.aureus, and Salmonella sp. were identified. The bacterial growth highly influenced electrical energy production in this method. The wastage of coffee produced more energy and grew more bacteria. Waste coffee had a maximum current density of 809.40 mA/m2 and a maximum power density of 10622.496 mW/m2, respectively. In contrast, the minimum current and power density values, 166.15 mA/m2 and 408.726 mW/m2, were attained, respectively. The produced energy is much higher than the information available in the literature. The applied method can be used in various sectors to generate electrical energy.

Sustainable Use of Marine Macroalga Sargassum muticum as a Biosorbent for Hazardous Crystal Violet Dye: Isotherm, Kinetic and Thermodynamic Modeling

The pollution of aquatic bodies by synthetic dyes is regarded as one of the most significant environmental issues, which has prompted greater research into effective and sustainable removal techniques. Even though there have been major efforts in the previous few decades, more study is still necessary to fully examine the long-term performance and usable applicability of adsorbents and different adsorption techniques for the removal of dye. In the present study, a brown marine macroalga Sargassum muticum was used as an effective and sustainable biosorbent for the crystal violet (CV) dye removal from aqueous solutions. The biosorbent was characterized by analysis of SEM, EDX, and FTIR. In order to evaluate the optimum conditions of CV biosorption, several parameters have been examined as a function of contact time, algal dose, initial concentration of CV, and pH. The maximum CV removal was obtained at 60 min contact time, 10 g/L algal dosage, 30 mg/L initial concentration of CV, and pH 6. The isothermal models of Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin are best explained the equilibrium data obtained. At the optimum conditions, the maximum biosorption capacity of the algal biomass achieved from the Langmuir model was 39.1 mg/g. The kinetic adsorption models were also better explained using the pseudo-second-order and Elovich model, and the effect of the boundary layer was indicated using the intraparticle diffusion model as well as the chemisorption-controlled biosorption process. Thermodynamically, the process of CV biosorption was shown to be random, spontaneous, and endothermic. Furthermore, the proposed mechanism of CV dye biosorption onto algal biomass is regulated by hydrogen bond formation, electrostatic interaction, and ion exchange. These findings revealed that the biomass of S. muticum is a sustainable and promising material for the biosorption of water pollutants.

Transformation of waste battery cathode material LiMn2O4 into efficient ultra-low temperature NH3-SCR catalyst: Proton exchange synergistic vanadium modification

It is essential to develop the catalyst for NH3-SCR with excellent performance at ultra-low temperature (≤150 °C), and resource recycling is another important part of environmental protection. Based on the principle of environmental friendliness, the LiMn2O4, one of the waste battery cathode materials, was successfully modified into a novel high-value catalyst for ultra-low temperature NH3-SCR through hydrogen ion exchange and two-dimensional vanadic oxide modification. The optimized LiMn2O4-0.5V-10H catalyst performed the best balance of NOx conversion and N2 selectivity, with activity reaching 96 % at 150 °C and N2 selectivity exceeding 70 % at ultra-low temperature. Due to the unique three-dimensional network structural characteristics of LiMn2O4 spinel, hydrogen exchange could exchange Li+ from the lattice and increase surface acidity; and a small amount of two-dimensional vanadic oxide loading could appropriately regulate redox ability and increase acidic sites. The in-situ DRIFTS results still showed that the L-H and E-R mechanisms coexisted during the reaction. Moreover, combining first-principles calculations and in-situ DRIFTS, the dual modification of H and V could enhance the adsorption of NH3 on the surface of LiMn2O4 but weaken the adsorption of NO, and promote the decomposition of nitrites while inhibit the formation of surface nitrate species, which was the core reason for the improvement of N2 selectivity. The modification mode in this work was simple and inexpensive, which provided a new idea for the high-value utilization of waste batteries and the design of NOx purification catalyst at ultra-low temperature.

Reconstruction of Metal Ions Extracted from Coal Gangue to Synthesize Cost-effective Adsorbent for Highly Efficient Removal of Pollutants.

An emerging "one stone, three birds" strategy was proposed to realize the value-added disposal of solid waste coal gangue (CG), the synthesis of superb adsorbent and the efficient decontamination of pollutants (i. e., dyes, heavy metals). In this process, the metal ions extrated from calcined coal gangue (CCG) was reconstituted by a one-step hydrothermal process to yield porous polymetallic silicate adsorbent (named HECCGA8h). The adsorbent has a high adsorption capacity of 270.27 and 185.53 mg/g for methylene blue (MB) and Cd(II), respectively. In the actual waters, the removal rate of MB by this adsorbent reaches 99.8% (in Yangtze River water) and 99.42% (in Seawater), and the removal rate of Cd(II) reaches 99.11% (in Yangtze River water) and 92.52% (in Seawater), respectively. Thermokinetic analysis showed that the adsorption of MB by HECCGA8h is spontaneous and endothermic with increased entropy, and the adsorption of Cd(II) is spontaneous and exothermic. The adsorption of MB is mainly driven by synergism of hydrogen bond, electrostatic attraction and ion exchange, and the adsorption of Cd(II) is mainly driven by the complexation and ion exchange between the surface group of the adsorbent and Cd(II). This research provides a new way for the realization of "treating waste with waste".

3R-IrO2 Two-Dimensional Nanosheets with Varying Layer Spacing and [IrO6] Distortion for OER

Here, two iridium-based crystal structures, K0.3IrO2·xH2O and Rb0.3IrO2·xH2O, have been synthesized for application in the oxygen evolution reaction (OER). The 3R-type layered IrO2 structures with different lattice parameters were successfully obtained from the two Ir structures by the hydrogen ion exchange method. According to synchrotron radiation spectra and the theoretical calculation of density functional theory (DFT), the increase of oxygen vacancy concentration caused by lattice distortion in the 3R-IrO2 crystal is negatively correlated with the activity of OER. A high concentration of oxygen vacancies will reduce Ir–O hybridization, which is not conducive to the balance between the adsorption and desorption of intermediate products. The higher OH adsorption energy barrier and band gap of the 3R-IrO2 crystal limited the improvement of electrochemical performance. In addition, through the analysis of the bonding orbitals and antibonding orbitals of the two structures, we concluded that 3R-IrO2 belongs to the nonthermodynamically stable structure and is not suitable for hydrogen production by electrolysis of water.

Screening of technologies for limiting the occurrence of disinfection by-products in urban water systems

Providing safe tap water while limiting the occurrence of disinfection by-products (DBPs) is probably one of the most challenging aspects of environmental chemical engineering within the urban water cycle. In the present work, an investigation about this challenge for the real water conditions of a full-scale drinking water treatment plant has been carried out. Five different and well-known technologies (four different aeration procedures, coagulation, hydrogen peroxide dosage, ion exchange and ultrafiltration) were studied in a real surface water matrix from an engineering point of view. A preliminary estimation of operation costs was also included. The study was focused primarily on trihalomethanes (THMs) and bromate, the DBPs currently regulated by the Spanish legislation, under the real treatment conditions of a drinking water treatment plant that distributes water to 100,000 inhabitants from a surface water reservoir. Based on the results, agitation aeration exhibited the greatest performance to remove THMs directly (86.46 % of removal). Ion exchange resin showed the best potential to inhibit their formation by 100 % bromide removal. Moreover, hydrogen peroxide dosage showed outstanding results in tests performed at full-scale for preventing the formation of bromate in the ozonation stage by 60 %. This was also the cheapest technology according to the dosage cost analysis performed, with 0.01 €·m−3. Thus, this investigation about the elimination of DBPs can be used as a reference to select the optimal treatment technology for limiting their occurrence under real working conditions for full-scale drinking water treatment plants.

Removal of F− from water by magnetic floriform magnesium zirconium hydrotalcite-like material doped with Fe2O3 and ZrO2

It is urgent to synthesize a kind of fluoride adsorbent with excellent fluorine removal performance in the field of treating fluorine-containing water. In this study, a magnetic floriform magnesium zirconium hydrotalcite-like material doped with Fe2O3 and ZrO2 was synthesized by urea hydrothermal method. Fe2O3 and ZrO2 particles and hexagonal laminae of hydrotalcite in the adsorption materials are uniformly stacked with each other. This structure allows the adsorbent to possess a large specific surface area (48.76 m2·g−1). The results of adsorption experiments indicate that the adsorption capacity of the adsorbent for fluoride can reach 113.38 mg·g−1. In addition, the adsorbent can be applied in a wide pH range (3–10) and has strong resistance to the effect of coexisting anions. After 5 cycles of adsorption, the fluorine removal performance of the adsorbent still maintained 80.93 % of the fresh adsorbent. Finally, DFT calculation of fluoride adsorption on the adsorbent was also carried out, and combined with the results of characterization and adsorption experiments, it is found that electrostatic attraction, hydrogen bond interaction, ion exchange and chemical adsorption are the main mechanisms of adsorption. Therefore, the material may be a potential fluoride adsorbent with good application prospect due to its various excellent properties.

Effects of banana peel compost rates on Swiss chard growth performance and yield in Shirka district, Oromia, Ethiopia

Increasing Population growth and expansion of urbanization lead to the emission of solid waste, including household waste, which causes environmental pollution. However, these wastes can be converted into forms used for organic farming. Therefore, the study was conducted to examine the effect of banana peel compost rates on the growth performance and yield of Swiss chard. The experiment took place in the Kulumsa Agricultural Research Center Greenhouse, with an area of 1.42m2 and pot area of 628cm2. The randomization of both treatments and replication was done by using Randomized Complete Block Design (RCBD). Field and laboratory data were subjected to one-way analysis of variance (ANOVA) by using general linear model (GLM) of the SAS statistical package version 9.0 to determine the existence of any statistical difference among the treatments. Soil and 10, 20, and30g rates of banana peel compost were characterized by a variety of plant nutrients. These include nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, micronutrients (iron, manganese, zinc, and molybdenum), power of hydrogen, organic carbon, and cat ion exchange capacity, carbon to nitrogen ratio, moisture content, and electrical conductivity. Each of plant nutrients were tested in the soil and banana peel compost rates(10, 20 and 30g), with nitrogen of 0.46, 1.54,1.93 and 2.58%; phosphorus of 1.51, 5.77, 5.8, and 5.91mg/kg, potassium of 11.82,41.28, 41.98, and 42.34mg/kg; calcium of 5.55, 25.04, 27.08, and 29.02mg/kg, magnesium of 6.2, 20.48, 22.88, and 23.93mg/kg; and sulfur of 5.79, 13.00, 14.38 and 16.45mg/kg/, respectively. Similarly, iron of 9.65, 15.72, 17.85, and 18.16mg/kg; manganese of 1.41, 4.23,6.38, and 8.91mg/kg; zinc of 1.17, 2.95, 4.25, and 5.60mg/kg; molybdenum of 0.53, 1.21,3.28, and 5.30mg/kg were tested, respectively. In addition to these, power of hydrogen was 6.34, 6.10, 6.22, and 7.30; organic carbon was 1.31, 15.0, 23.47, and 25.50%; carbon to nitrogen ratio was 2.85, 9.81, 12.16, and 9.88; cat ion exchange capacity was 21.08, 24.21, 34.58, and 36.94 (cmol (+) /kg; moister content was 5.75,7.24, 8.81, and 9.85%; and electrical conductivity was 0.11, 2.06, 3.23, and 4.09(ds/cm), respectively, for soil and 10, 20, and 30g rates of banana peel compost. The height of the plants, the number of leaves, the leaves area, the leaves area index (LAI), the length of the leaf and the width of the leaves were all parameters of Swiss chard growth performance based. Each of the Swiss Chard growth parameters was measured in 10g, 20g, and 30g treatments, with average plants height of 22.00, 24.67 and 26.33 cm, average leaves number of 9.00, 12.00 and 8.00, average leaves area of 111.33 and 134.30cm2and average leaves width of 8.33, 10.80, and 12.77cm, respectively. Similarly, the mean leaves area index (LAI) was 0.10, 0.30, and 0.5; leaves length was 12.80, 13.00, and 14.67cm, respectively, for 10g, 20g, and 30g treatments. In addition to the Swiss chard growth parameters, the Swiss chard yield parameters have also been measured. Fresh and dry weights were the Swiss chard yield parameters. For each treatment (10g, 20g and 30g), fresh weights 2.44, 2.03 and 3.41g, and dry weights 0.11, 0.08 and 0.14g were recorded, respectively. In conclusion, all the rates of banana peel compost were enhanced and improved Swiss chard growth performance and yield, better than the no compost control.

Adsorption of Ag/Au nanoparticles by ordered macro-microporous ZIF-67, and their synergistic catalysis application

Silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) are universally used in diverse fields, but the use and treatment of various commodities will adversely affect the human health. Therefore, the recovery and immobilization of AgNPs and AuNPs from wastewater has important economic and social benefits. The ordered macro-microporous ZIF-67 single crystal (SOM-ZIF-67) was prepared by double solvent-assisted strategy. It was used as an adsorbent to remove precious metal pollutants, AuNPs and AgNPs. Under the optimal experimental conditions, the adsorption process of nanoparticles on SOM-ZIF-67 conformed to the pseudo-second-order kinetics. The theoretical maximum adsorption capacity of SOM-ZIF-67 towards AgNPs and AuNPs was 1250 mg g−1 and 2000 mg g−1, respectively. Through some characterization methods, it can be inferred that the adsorption mechanism might include ion-dipole interaction, metal-ligand interaction, and hydrogen bond, chelation and ion exchange between AgNPs/AuNPs and nitrogen and oxygen atom, and reduction etc. Furthermore, the interpenetrating macropores and micropores of SOM-ZIF-67 further promoting the adsorption capacity. Meanwhile, after the adsorption, the composite material (SOM-ZIF-67@AgNPs or SOM-ZIF-67@AuNPs) was developed as a new kind of heterogeneous catalyst that had good catalytic activity and cycle catalytic performance for 4-nitrophenol in the presence of NaBH4. At last, the adsorbent and catalyst could be regenerated. Simultaneously recycling of precious noble metal was also possible. Thus, the prepared SOM-ZIF-67 was a potential green adsorbent for the removal and recovery of precious metal nanoparticles. The secondary utilization as an effective catalyst would elaborate the sustainability of the method.

The Solar Wind with Hydrogen Ion Exchange and Large-scale Dynamics (SHIELD) Code: A Self-consistent Kinetic–Magnetohydrodynamic Model of the Outer Heliosphere

Abstract Neutral hydrogen has been shown to greatly impact the plasma flow in the heliosphere and the location of the heliospheric boundaries. We present the results of the Solar Wind with Hydrogen Ion Exchange and Large-scale Dynamics (SHIELD) model, a new, self-consistent, kinetic–MHD model of the outer heliosphere within the Space Weather Modeling Framework. The charge exchange mean free path is on the order of the size of the heliosphere; therefore, the neutral atoms cannot be described as a fluid. The numerical code SHIELD couples the MHD solution for a single plasma fluid to the kinetic solution for neutral hydrogen atoms streaming through the system. The kinetic code is based on the Adaptive Mesh Particle Simulator, a Monte Carlo method for solving the Boltzmann equation. The numerical code SHIELD accurately predicts the increased filtration of interstellar neutrals into the heliosphere. In order to verify the correct implementation within the model, we compare the results of the numerical code SHIELD to those of other, well-established kinetic–MHD models. The numerical code SHIELD matches the neutral hydrogen solution of these studies as well as the shift in all heliospheric boundaries closer to the Sun in comparison with the multi-fluid treatment of neutral hydrogen atoms. Overall the numerical code SHIELD shows excellent agreement with these models and is a significant improvement to the fluid treatment of interstellar hydrogen.

The Impact of Kinetic Neutrals on the Heliotail

Abstract The shape of the heliosphere is thought to resemble a long, comet tail, however, recently it has been suggested that the heliosphere is tailless with a two-lobe structure. The latter study was done with a three-dimensional (3D) magnetohydrodynamic code, which treats the ionized and neutral hydrogen atoms as fluids. Previous studies that described the neutrals kinetically claim that this removes the two-lobe structure of the heliosphere. In this work, we use the newly developed Solar-wind with Hydrogen Ion Exchange and Large-scale Dynamics (SHIELD) model. SHIELD is a self-consistent kinetic-MHD model of the outer heliosphere that couples the MHD solution for a single plasma fluid from the BATS-R-US MHD code to the kinetic solution for neutral hydrogen atoms solved by the Adaptive Mesh Particle Simulator, a 3D, direct simulation Monte Carlo model that solves the Boltzmann equation. We use the same boundary conditions as our previous simulations using multi-fluid neutrals to test whether the two-lobe structure of the heliotail is removed with a kinetic treatment of the neutrals. Our results show that despite the large difference in the neutral hydrogen solutions, the two-lobe structure remains. These results are contrary to previous kinetic-MHD models. One such model maintains a perfectly ideal heliopause and does not allow for communication between the solar wind and interstellar medium. This indicates that magnetic reconnection or instabilities downtail play a role for the formation of the two-lobe structure.

A new comprehensive evaluation of the corrosion mechanism of E-type glass fibers in sulfuric acid solutions

The corrosion mechanism of the glass fibers (GFs) in the sulfuric acid environments with different times, temperatures, and concentrations were studied. The change of surface morphology, weight, composition, and tensile strength of the GFs in the corrosion process was discussed. The results indicated that the evolution of surface morphology, weight, and composition of the E-type GFs was increased by raising the significant investigated parameters. Moreover, the response surface morphology (RSM) was applied to analyze the corrosion process comprehensively. The effects of variables on the tensile strength retention (TSR) of E-type GFs and the relative pH (pHR) of the sulfuric acid solution have been investigated. The predicted TSR and pHR values had correlation coefficient higher than 90% with experimental observation, according to the obtained RSM model. The RSM model established that the special effects of the H2SO4 concentration elevated more than temperature and time on the corrosion process of E-type GFs. Finally, the corrosion mechanism of E-type GFs in sulfuric acid was attributed to two main reactions, including metal with hydrogen ion exchange reactions and fracturing of the Si-O-Si band. The results evaluated that the RSM is a very suitable approach for analyzing and modeling of the corrosion mechanism of E-type GFs in sulfuric acid.

The Confinement of the Heliosheath Plasma by the Solar Magnetic Field as Revealed by Energetic Neutral Atom Simulations

Abstract Traditionally, the solar magnetic field has been considered to have a negligible effect in the outer regions of the heliosphere. Recent works have shown that the solar magnetic field may play a crucial role in collimating the plasma in the heliosheath. Interstellar Boundary Explorer (IBEX) observations of the heliotail indicated a latitudinal structure varying with energy in the energetic neutral atom (ENA) fluxes. At energies ∼1 keV, the ENA fluxes show an enhancement at low latitudes and a deficit of ENAs near the poles. At energies >2.7 keV, ENA fluxes had a deficit within low latitudes, and lobes of higher ENA flux near the poles. This ENA structure was initially interpreted to be a result of the latitudinal profile of the solar wind during solar minimum. We extend the work of Kornbleuth et al. by using solar minimum–like conditions and the recently developed Solar-wind with Hydrogen Ion Exchange and Large-scale Dynamics (SHIELD) model. The SHIELD model couples the magnetohydrodynamic plasma solution with a kinetic description of neutral hydrogen. We show that while the latitudinal profile of the solar wind during solar minimum contributes to the lobes in ENA maps, the collimation by the solar magnetic field is important in creating and shaping the two high-latitude lobes of enhanced ENA flux observed by IBEX. This is the first work to explore the effect of the changing solar magnetic field strength on ENA maps. Our findings suggest that IBEX is providing the first observational evidence of the collimation of the heliosheath plasma by the solar magnetic field.

Identification and characterization of gene in

Toxoplasma gondii is an obligate intracellular protozoan that causes toxoplasmosis. Previous studies have shown that the perturbation of mitochondrial metabolism in T. gondii results in growth deficiency in host cells and lack of virulence in animals. Members of this Letm1 protein family are inner mitochondrial membrane proteins which play a role in potassium and hydrogen ion exchange. Letm1 has not been characterized in T. gondii. In this study, a potential TgLetm1 gene (TgGT1_288400) with Letm1-like protein domain coding sequence was identified in T. gondii. Indirect immunofluorescence assays suggested that TgLetm1 localized to the mitochondria in tachyzoites, as indicated by the colocalization with mitochondrial marker Mitotracker. TgLetm1 was found in the membrane fraction by western blot analysis. To investigate the role of TgLetm1 in T. gondii, we generated a tetracycline-inducible TgLetm1-knock-down mutant. The conditional deletion of TgLetm1 resulted in mitochondrial swelling. Functional studies showed that the conditional deletion of TgLetm1 resulted in growth inhibition, deficiency in invasion and replication, and lack of virulence in mice.

(Invited) Electrochemical Generation of Fuels: Matching Research and Application for Advanced Water Splitting and Other Technologies

Electrochemistry is becoming increasingly important in transitioning from primarily fossil fuel based energy sources to more renewable options. This challenge will require a combination of solutions, depending on geography, the mix of renewables, and other factors. The intermittent nature of wind, solar, and other forms of renewable energy, as well as demand fluctuations which do not match the generation capacity, drives the need for modular, distributed energy storage solutions, where electrochemistry can be ideal. However, for very long storage times, conversion of energy to a chemical fuel is often the most practical solution. Electrochemical generation of fuels such as hydrogen, ammonia, and CO2-derived hydrocarbons are all related and have similar R&D challenges. In addition, all of these chemicals have different advantages and disadvantages, and have benefits in different scenarios. This talk will focus on some of the considerations in developing a new electrochemical device, and research challenges applicable to low temperature electrochemical fuel generation. While fundamental research in understanding electrocatalytic reactions at the molecular level is valuable from a basic science perspective, understanding the application requirements for each market, and pricing structure vs. scale, can guide application of this research to the next logical stage. There is a large application space for fuels and industrial chemicals with widely varying price points based on scale and requirements. For example, different ground vehicle classes (consumer vehicles, heavy duty trucks, fork trucks, industrial equipment etc.,) may each be best served by different fuels depending on power and range requirements as well as customer preferences. Ships and airborne vehicles may have different optimal solutions. Smaller scale or emerging markets such as unmanned vehicles may also serve as easier market entry points. At the materials discovery stage, all of the above reactions require catalyst design and fundamental understanding in order to achieve high activity and efficiency. Specifically for ammonia and carbon-based fuels, selectivity is a key issue, and structural approaches to control the active site and competition for binding sites are being pursued. Beyond the catalyst, the electrode structure and integration also need to be designed for optimal performance, including effective fluid flow and catalyst access. While the individual catalyst composition and structures will be different, all of these pathways involve hydrogen or oxygen evolution reactions and ion exchange membranes, and can both leverage and inform electrolysis research. Proton’s work in these areas will be discussed, as well as key needs for additional research and collaborations between applied and fundamental science.

Selective Proton/Deuteron Transport through Nafion|Graphene|Nafion Sandwich Structures at High Current Density.

Ion current densities near 1 A cm-2 at modest bias voltages (<200 mV) are reported for proton and deuteron transmission across single-layer graphene in polyelectrolyte-membrane (PEM)-style hydrogen pump cells. The graphene is sandwiched between two Nafion membranes and covers the entire area between two platinum-carbon electrodes, such that proton transfer is forced to occur through the graphene layer. Raman spectroscopy confirms that buried graphene layers are single-layer and relatively free of defects following the hot-press procedure used to make the sandwich structures. Area-normalized ion conductance values of approximately 29 and 2.1 S cm-2 are obtained for proton and deuteron transport, respectively, through single-layer graphene, following correction for contributions to series resistance from Nafion resistance, contact resistance, etc. These ion conductance values are several hundred to several thousand times larger than in previous reports on similar phenomena. A ratio of proton to deuteron conductance of 14 to 1 is obtained, in good agreement with but slightly larger than those in prior reports on related cells. Potassium ion transfer rates were also measured and are attenuated by a factor of many thousands by graphene, whereas proton transfer is attenuated by graphene by only a small amount. Rates for hydrogen and deuterium ion exchange across graphene were analyzed using a model whereby each hexagonal graphene hollow site is assumed to transmit ions with a specific per-site ion-transfer self-exchange rate constant. Rate constant values of approximately 2500 s-1 for proton transfer and 180 s-1 for deuteron transfer per site through graphene are reported.

Properties of Polyurethane Coatings Based on Linseed Oil Phosphate Ester Polyol

Linseed oil was epoxidized using hydrogen peroxide (H2O2), acetic acid (AcOH) and ion exchange resin Amberlite IR-120 as a catalyst. Epoxidized oil was separately dissolved in isopropyl alcohol (IPA) or diethylene glycol butyl ether (DGBE) and phosphorylated with different amounts of phosphoric (H3PO4) acid (1%, 2%, 3% and 5%). The formation of phosphate polyesters was confirmed by Fourier-transform infrared (FTIR) and 31P nuclear magnetic resonance (NMR) spectra. Based on the synthesized polyols, polyurethane (PU) coatings were prepared. PU coating based on linseed oil diethylene glycol ester polyol was used as the reference. For the characterization of coatings, mechanical tests and thermogravimetric analysis (TGA) were used. The flammability parameters of wood samples with PU coatings at a heat flux of 35 kW/m2 were determined. It was found that PU coatings based on IPA polyols had higher mechanical characteristics, char residue upon thermal decomposition and flame retardancy.

Hierarchical yolk-shell WO3 microspheres with highly enhanced photoactivity for selective alcohol oxidations

Hierarchical WO3 microspheres with controllable interior structures from solid, yolk-shell, to hollow were synthesized through sonochemical precipitation and hydrogen ion-exchange routes followed by thermal treatment. During the photocatalytic selective oxidation of aromatic alcohols to their corresponding aldehydes in aqueous medium under light irradiation with full wavelengths, the yolk-shell WO3 microspheres exhibited much higher photocatalytic activity than those WO3 microspheres with solid and hollow structures, respectively. This superior activity of the yolk-shell WO3 microspheres can be attributed to the synergistic promoting effect of the following factors: firstly, the porous structure constructed by self-assembly of the interconnected nanosheets together with high surface area promoted the light harvesting and also facilitated the adsorption and diffusion of reactant molecules; secondly, the small crystallite size favored the rapid transfer of photoelectrons, which diminished the transfer distance of photoelectrons and thus inhibited their recombination with holes; thirdly, the yolk-shell structure enhanced light harvesting via multiple reflections in the yolk-shell chambers. Meanwhile, all the WO3 photocatalysts displayed excellent durability against structural collapse due to the robust hierarchical structures. This work identifies the important role of yolk-shell structure played in photocatalytic selective oxidation of aromatic alcohols.