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This paper summarizes an innovative demonstration by the Minnesota Department of Transportation (MnDOT) of the distance-based fee (DBF) concept. Fees based on actual road usage, as opposed to fuel consumption, have been explored by numerous states as an alternative transportation revenue source to the motor fuel tax. These approaches rely on the collection of road usage data, and most states have pilot tested approaches reliant on aftermarket devices installed within individually owned vehicles. Private-sector vendors are responsible for managing data collection, fee assessment, and account management. In the near term, the most feasible and scalable option for DBF deployment may be to leverage embedded telematics technologies under a fleet-based reporting and collection approach. MnDOT worked with two shared mobility (SM) providers offering carsharing services in the Minneapolis–St. Paul region. A connected and automated vehicle (C/AV) partner was also included to demonstrate the collection of road usage information from emerging C/AV technologies. The demonstration successfully collected the required information for DBF assessment from the SM and C/AV providers including information necessary to support audits by the Minnesota Department of Revenue. The demonstration showed that the information necessary for assessing and collecting DBF could be obtained from embedded telematics systems and reported by a fleet provider on behalf of all users in that fleet. Although the specific architecture demonstrated would probably need significant adaption for scaling to a national system, it nonetheless provides insights that support development of a broader ecosystem of usage-based charging strategies.

Funding: The authors are grateful to the Ministry of Human Resource Development of the Government of India for financial support through the SPARC initiative (project: SPARC/2018-2019/P307/SL). One of the authors (AM) is thankful to MANIT, Bhopal for providing fellowship support. Herein, the efficiency of an ordered mesoporous carbon (OMC), synthesized through metal and halide free pathways, is evaluated to remove an anionic dye Chrysoidine R through fixed-bed adsorption. Potentially toxic azo dye, Chrysoidine R, was employed as a test and encouraging results are obtained. The bulk removal of the dye was accomplished with 99.77% column saturation and treatment of the exhausted bed of adsorbent with a suitable eluent resulted in almost 100% dye-recovery. The efficiency of the column remained almost unchanged in five adsorption/desorption cycles. The fixed-bed column studies clearly reveal that the OMC is a highly efficient and robust material for large-scale wastewater treatment applications. Publisher PDF

The authors are grateful to the Ministry of Human Resource Development of the Government of India for financial support through the SPARC Project- SPARC/2018–2019/P307/SL. One of the authors (Asna Mariyam) is also grateful to MANIT, Bhopal for providing fellowship assistance. We thank the University of St Andrews for a PhD scholarship for FS. We acknowledge EPSRC Strategic Resources Grant (EP/R023751/1). The present report is an outcome of investigations to assess the adsorptive potential of a synthesized metal- and halide-free variant of ordered mesoporous carbon (OMC) towards an anionic azo dye, Methyl Orange. The results of preliminary studies, carried out in batch mode, helped in setting up the process variables to achieve optimum adsorption conditions. The experimental data were then fitted to Langmuir, Freundlich, Temkin, and Dubinin-Radushkevitch isotherm models. The equilibrium data fitted well to the Langmuir model at 303 K and the monolayer adsorption capacity was 0.33 mmol g−1. The adsorption kinetics were explored by fitting the data to pseudo-first-order and pseudo-second-order kinetic models. The latter described the kinetics well, as indicated by higher regression coefficients. To elucidate the mechanism of mass transfer, various well-known mathematical models were employed. The adsorption of the dye was found to involve particle diffusion. Thermodynamic studies revealed that the adsorptive uptake of Methyl Orange by the OMC was spontaneous (ΔG0 = −23.71 kJ mol−1) and exergonic (ΔH0 = −123.15 kJ mol−1). Finally, the bulk removal of the anionic dye was investigated through column operations followed by column regeneration (desorption) studies. Column saturation of up to 96.55% could be realized. Values for dye recovery reached up to 93.26%. The column efficiency was then evaluated by carrying out three consecutive adsorption/desorption cycles. The results obtained indicated that the adsorbent has a good ability to eliminate Methyl Orange from wastewater, both in batch and column operations. Postprint

Funding: Support by the Chinese Scholarship Council and the University of St Andrews for a stipend (Z. Y.) are gratefully acknowledged. Electron microscopy was carried out at the Electron Microscopy Facility, School of Chemistry, University of St Andrews and we acknowledge recent funding for the Facility from the EPSRC (EP/T019298/1, EP/L017008/1) and the EPSRC Strategic Resources Grant (EP/R023751/1). A scheme for the electrodeposition of ultrathin bimetallic layers on top of a self-assembled monolayer (SAM) is investigated which combines the deposition of one metal (Pd) coordinated to a functionalized SAM (3-(4-pyridine-4-yl-phenyl)-propane-1-thiol, PyP3) on Au/mica with another metal (Cu) from the bulk electrolyte. The coordination-controlled electrodeposition (CCED) is a four-phase process comprising (i) Pd2+ coordination to the terminal pyridine units of the SAM, (ii) reduction of Pd and nanoparticle formation, (iii) formation of an intermixed shell of Pd and Cu, and (iv) deposition of bulk Cu. Chronoamperometry reveals a fast nucleation phase where Pd nanoparticles form within a few milliseconds and seed the Cu deposition. The Pd-Cu core-shell nature of deposited nanoparticles is confirmed by transmission electron microscopy (TEM). Harnessing the selective coordination of Pd2+ to PyP3, a one-pot procedure is further developed using electrolytes containing both Pd2+ and Cu2+ ions. Thus simplifying complexation and reduction, continuous Pd/Cu films are obtained in a multistep process as verified by scanning tunneling microscopy (STM). With a percolation threshold below 3 nm, CCED, as a SAM-controlled deposition strategy, offers an avenue for generation of ultrathin films. Publisher PDF

A simulation methodology for calculating the lattice parameter and oxygen ion migration energy of ceria-based electrolyte formulations is devised. The results are analysed and benchmarked against experimentally obtained values to verify the efficacy of the simulation methodology. A total of 26, 2 x 2 x 2 samarium (Sm)- and gadolinium (Gd)-doped supercells of different compositions and doping profiles were modelled and simulated by molecular mechanics force field methods using CP2K. The results of the computational simulations are comparable with those obtained experimentally, especially when there are equal amounts of Sm and Gd dopants in the structure. Simulation results can also provide insights into the mechanisms of ionic conduction. The incongruence of the computational and experimental results is attributed to the limitations of the molecular mechanics force field methodology utilised, with the expectation that an ab initio density functional theory (DFT) calculation would yield closer conformance.

The authors thank the University of St Andrews for a PhD scholarship for FS. Raman Spectroscopy was performed at the Light Element Analysis Facility (EPSRC grant EP/T019298/1), University of St Andrews, and we acknowledge EPSRC Strategic Resources Grant (EP/R023751/1). The preparation of mesoporous carbons possessing a highly ordered body centred cubic (bcc) arrangement of pores by employing a halide- and metal-free synthesis method is reported. Products were characterised using gas physisorption, Small Angle X-ray Diffraction and X-ray Scattering, Raman spectroscopy and High Resolution Transmission Electron Microscopy (TEM). The materials produced in this work had Specific Surface Areas of between 422 and 988 m2g−1 and pore diameters of around 7 nm. From the TEM images, high quality Digital Diffraction Patterns, relating to the ordered mesopore structure, were obtained. On increasing calcination temperature from 350 to 1000°C the bcc structure was retained but its dimensions decreased progressively as the mesopore structure shrank. The effects on the structure and texture of the materials of the three key parameters of polymerisation time and the concentrations of the two catalysts employed, NH4OH and oxalic acid, were studied. Shorter polymerisation times and lower catalyst concentrations gave rise to the most well-ordered products whereas longer polymerisation times with higher concentrations of base and acid catalyst resulted in disordered pore structures. Publisher PDF

The authors are grateful to the Ministry of Human Resource Development of the Government of India for financial support through the SPARC initiative (project: SPARC/2018-2019/P307/SL). We thank the University of St Andrews for a PhD studentship for FS. TEM was carried out at the Electron Microscopy Facility, School of Chemistry, University of St Andrews. One of the authors (Asna Mariyam) is thankful to MANIT, Bhopal for providing fellowship support. Herein, an ordered mesoporous carbon (OMC) material was prepared using a metal and halogen free method, and its adsorptive potential for the cationic dye, ‘Methylene Blue’ (MB), was investigated. Batch studies were carried out to determine the influence of pH, dye concentration, adsorbent quantity, and contact time on adsorption behaviour. Adsorption models based on Langmuir, Freundlich, Temkin and Dubinin-Radunkevich isotherms were validated and the thermodynamic variables governing the nature and feasibility of reaction were evaluated. Values of the adsorption uptake at equilibrium (qe) decreased as the temperature was increased, suggesting thereby that the adsorption process involved was exothermic. Kinetic studies indicated that adsorption obeyed pseudo-second order behaviour and operated via a ‘film-diffusion’ mechanism. When attempts were made to carry out bulk removal of MB using a fixed bed adsorption column, 99.5% saturation could be achieved. Desorption of MB from the used column was performed and dye recovery was almost 100% in the first cycle and on 5th cycle 99% of dye was obtained. This pattern clearly indicates that for the cationic dye MB, OMC acts as a highly efficient and robust adsorbent. Publisher PDF

Ordered mesoporous carbon (OMC) was employed as a support for palladium nanoparticles in catalysts for the gas phase hydrodechlorination (HDC) of trichloromethane (TCM). 1 wt% palladium was incorporated using three methods: incipient wetness (IW), a dilute solution (DS) method, and a solid-liquid (SL) method. The effect of the preparation method on catalyst structure and activity was investigated. Catalyst composition and nanostructure were studied using gas physisorption, high specification transmission electron microscopy and X-ray photoelectron spectroscopy. Catalytic conversion and product selectivities were determined in steady-state activity tests at temperatures between 70 and 300 &deg, C. Two of the catalysts (IW and DS) showed excellent dispersion of fine Pd nanoparticles of average diameter ~2 nm. These materials showed excellent activity for HDC of TCM which compares favourably with the performance reported for Pd on amorphous carbon catalysts. In addition, they showed relatively high selectivities to the more valuable higher hydrocarbons. However, the SL method gave rise to catalysts with larger particles (~3 nm) and a less uniform palladium distribution. This resulted in lower conversion and lower selectivities to higher hydrocarbons and in more severe catalyst deactivation at the highest reaction temperatures.

This work has received financial support from FEDER/MINECO (MAT2017‐87579‐R, MAT2016‐81118‐P, and MTM2016‐74983‐C2‐2‐R). NetmeetData Project from Fundación BBVA convocatoria 2020. Junta de Andalucía is also acknowledged (MULTITOM Project, P18‐FR‐1422 Project FQM334, FQM355). J.M.M. acknowledges the Youth Employment Program (Plan de Empleo Juvenil) of Junta de Andalucía. Electron microscopy data were acquired using the equipment at the DME‐UCA node of the ELECMI Spanish Unique Infrastructure for Electron Microscopy of Materials. The authors thank the University of St. Andrews for a Ph.D. scholarship for F.S. A novel procedure to optimize the 3D morphological characterization of nanomaterials by means of high angle annular dark field scanning‐transmission electron tomography is reported and is successfully applied to the analysis of a metal‐ and halogen‐free ordered mesoporous carbon material. The new method is based on a selection of the two parameters (μ and β) which are key in the reconstruction of tomographic series by means of total variation minimization (TVM). The parameter‐selected TVM reconstructions obtained using this approach clearly reveal the porous structure of the carbon‐based material as consisting of a network of parallel, straight channels of ≈6 nm diameter ordered in a honeycomb‐type arrangement. Such an unusual structure cannot be retrieved from a TVM 3D reconstruction using default reconstruction values. Moreover, segmentation and further quantification of the optimized 3D tomographic reconstruction provide values for different textural parameters, such as pore size distribution and specific pore volume that match very closely with those determined by macroscopic physisorption techniques. The approach developed can be extended to other reconstruction models in which the final result is influenced by parameter choice. Postprint Postprint

Authors thank the University of St Andrews for the PhD scholarship of FS. We acknowledge funding from MINECO/FEDER (Projects MAT2017-87579-R and MAT2016-81118-P) and from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 823717 –ESTEEM3. Ordered mesoporous cerias were synthesised by employing metal- and halogen- free ordered mesoporous carbons (OMCs) as the hard templates in a ‘nanocasting’ procedure. TEM, small angle (SA) and wide angle (WA) XRD, and N2 physisorption analyses were used to characterise the templates, intermediates and ceria products and electron tomography (STEM-HAADF) was used to explore the 3D morphology of the ceria nanostructures grown within the carbon templates. This allowed the relationships between the structures of the OMC templates and the products to be considered in detail as two parameters were varied. These were: the method of impregnation of the ceria precursor; and the temperature of calcination of the OMC template. Of the four impregnation methods tested, the solid-liquid method was found to be the most successful. This gave a high quality product with the highest yield of uniform mesopores, and crystalline nanorods of ceria arrayed in clear long-range order, as viewed by TEM and determined in SA and WAXRD. The specific surface area and pore volume exhibited by this sample were 111 m2/g and 0.39 cm3/g, respectively. 3D electron tomography reconstructions revealed the presence of a network of ordered, nanoscale, rod-like structures interlinked in a complex fashion. The effect of calcination temperature of the template on uptake of the ceria precursor during impregnation was studied by calcining OMCs at temperatures from 350 to 800 °C and using these as hard templates for the nanocasting of ceria. Of these, the carbon template calcined at 400 °C gave the highest quality product. Publisher PDF

The authors thank the University of St Andrews and the UK Engineering and Physical Sciences Research Council for the PhD studentship for AVC-A (grant code: EP/M506631/1). Electron microscopy was performed at the Electron Microscope Facility, University of St Andrews. In a systematic study, two compositional series of ceria-based oxides, both co-doped with Sm and Gd, were synthesised using a low temperature method and evaluated as oxygen ion-conducting electrolytes for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs). Series one, Ce1-2xSmxGdxO2-x, had equal concentrations of Sm and Gd but varying total dopant concentration. Series two, Ce0.825SmxGd0.175-xO1.9125, had a fixed total dopant concentration but the Sm:Gd concentration ratio was varied. The materials were characterised using scanning and transmission electron microscopy, inductively coupled plasma mass spectrometry and X-ray diffraction. Impedance spectra were recorded on dense pellets of these materials. From these, total, bulk and grain boundary conductivities and capacitances along with activation energies, pre-exponential constants and enthalpies of ion migration and defect association were obtained. These gave a detailed insight into the fundamental conduction processes in the materials. Ce0.825Sm0.0875Gd0.0875O1.9125 had the highest total ionic conductivity at temperatures of 550 °C and above and also demonstrated an enhanced conductivity with respect to its singly-doped parent compounds, Ce0.825Sm0.175O1.9125 and Ce0.825Gd0.175O1.9125, at 400 °C and above. This compares favourably with previously-reported values and has promising implications for the development of IT-SOFCs. Postprint

In this work, nanostructured Ce0.9Gd0.1O2-δ (GDC) and Ce0.9Pr0.1O2-δ (PrDC) spheres previously obtained by microwave assisted hydrothermal homogeneous co-precipitation were impregnated with 1 wt% Pd by the incipient wetness impregnation by an aqueous Pd2+ solution. Their properties were characterized by synchrotron radiation X-ray diffraction (SR-XRD), X-ray absorption near-edge spectroscopy (XANES) and scanning and high resolution electron microscopy with X-ray spectroscopy. Spherical particles with average diameters around 200 nm were found to consist of crystallites of average size, 10 nm, with small particles of PdO finely dispersed over the sphere surface. In situ XRD and XANES experiments were carried out under reducing and oxidizing conditions in order to investigate the redox behaviour of these materials and to evaluate the effect of Pd loading on the oxidation state of Ce. All of the lanthanide-doped ceria (LnDC) supports were found to have a cubic crystal structure (Fm3m space group). An increase in lattice parameters was observed under reducing conditions which was attributed to the reduction of Ce4+ ions to the larger Ce3+ ions, and to the associated increase in oxygen vacancy (VO) concentration. Addition of Pd to the LnDC spheres increased their Ce3+ content. Finally, catalytic tests for CH4 combustion were performed on the LnDC and Pd/LnDC nanocatalysts. The best performance was observed in samples with 1 wt% Pd loading, which exhibited T50 values (temperature at which 50% of CH4 conversion was reached) close to 310 °C. These values are 220 °C and 260 °C lower than those obtained for nanostructured PrDC and GDC spheres alone, respectively. Fil: Fuentes, Rodolfo Oscar. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Acuña, Leandro Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina Fil: Leyva, A. Gabriela. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina Fil: Baker, Richard T.. University of St. Andrews; Reino Unido Fil: Pan, Huiyan. Universidad de Cádiz; España Fil: Chen, Xiaowei. Universidad de Cádiz; España Fil: Delgado Jaén, Juan J.. Universidad de Cádiz; España

Funding from Higher Education Commission (HEC) of Pakistan under NRPU program (grant number 4430 and 5911) is greatly acknowledged to carry out this research. Funding for Ms Iram Aziz, lead author, was provided by British Council to carry out part of this work in University of St. Andrews, UK, and by HEC under Indigenous PhD Fellowship Program. Non-precious metal-based electrocatalysts on carbon materials with high durability and low cost have been developed to ameliorate the oxygen-reduction reaction (ORR) and oxygen-evolution reaction (OER) for electrochemical energy applications such as in fuel cells and water electrolysis. Herein, two different morphologies of FeNi/NiFe2O4 supported over hierarchical N-doped carbons were achieved via carbonization of the polymer nanofibers by controlling the ratio of metal salts to melamine: a mixture of carbon nanotubes (CNTs) and graphene nanotubes (GNTs) supported over carbon nanofibers (CNFs) with spherical FeNi encapsulated at the tips (G/CNT@NCNF, 1 : 3), and graphene sheets wrapped CNFs with embedded needle-like FeNi (GS@NCNF, 2 : 3). G/CNT@NCNF shows excellent ORR activity (on-set potential: 0.948 V vs. RHE) and methanol tolerance, whilst GS@NCNF exhibited significantly lower over-potential of only 230 mV at 10 mA cm-2 for OER. Such high activities are due to the synergistic effects of bimetallic NPs encapsulated at CNT tips and N-doped carbons with unique hierarchical structures and the desired defects. Publisher PDF

Non-precious metal-based electrocatalysts on carbon materials with high durability and low cost have been developed to ameliorate the oxygen-reduction reaction (ORR) and oxygen-evolution reaction (OER) for electrochemical energy applications such as in fuel cells and water electrolysis. Herein, two different morphologies of FeNi/NiFe

Catalysts of 2 wt% Pd/Sm-doped Ceria (SDC) were prepared and evaluated for hydrogen production by methanol reforming. Three preparation methods were used: a one-step method in which formation of the SDC phase and Pd incorporation took place in a single citrate-complexation process (Method A); impregnation of pre-prepared SDC nanopowder supports using Pd(NO3)2 solution (Method B); and impregnation of pre-prepared SDC from H2PdCl4 solution (Method C). Both methanol conversion and hydrogen yield increased as: bare supports

This work analyses the deactivation of activated carbon-supported Rh and Ru (both at 1 wt%) catalysts (Rh/C and Ru/C) in the hydrodechlorination (HDC) of dichloromethane (DCM) and chloroform (TCM). The deactivation can be mainly attributed to the coverage of active metal centres by organometallic species resulting from the chemisorption of reaction products, such as olefins, at the electro-deficient metal sites. With DCM, the activity of Ru/C decreased by more than 80% after 90 h on stream at 250 °C and with a space time of 1.7 kg h mol−1. Under the same conditions, with TCM, the Rh/C and Ru/C catalysts lost 75% of activity after 84 and 54 h on stream, respectively. A regeneration treatment with air at 250 °C allowed complete recovery of the catalytic activity. After each deactivation-regeneration cycle, the selectivity to olefins increased. Therefore, HDC with the catalysts tested provides a promising way for the upgrading of chloromethanes from waste gas streams into light olefins.

The authors thank the University of St Andrews and the UK Engineering and Physical Sciences Research Council for the PhD studentship for AVC-A (grant code: EP/M506631/1). Cerias, appropriately doped with trivalent rare earth ions, have high oxide ion conductivity and are attractive SOFC (solid oxide fuel cell) electrolytes. Here, seven compositions of Ce0.8SmxGdyNdzO1.9 (where x, y and z = 0.2, 0.1, 0.0667 or 0 and x + y + z = 0.2) are synthesised using a low temperature method in order to determine the effect of multiple doping on microstructure and conductivity. Analysis using scanning and transmission electron microscopy, inductively coupled plasma mass spectrometry, X-ray diffraction and impedance spectroscopy is carried out. Crystallite sizes are determined in the powders and relative densities and grain size distributions were obtained in sintered pellets. Total, bulk and grain boundary conductivities are obtained using impedance spectroscopy and corresponding activation energies and enthalpies of ion migration and defect association are calculated. The highest total conductivity observed at 600 °C is 1.80 Sm−1 for Ce0.8Sm0.1Gd0.1O1.9 and an enhancement effect on conductivity for this combination of co-dopants between 300 °C and 700 °C relative to the singly doped compounds - Ce0.8Sm0.2O1.9 and Ce0.8Gd0.2O1.9 - is seen. This has interesting implications for their application as SOFC electrolytes, especially at intermediate temperatures. Postprint

This work is supported through the EPSRC (UK) critical mass research grant EP/J0118O58/1 awarded to PLG and EDB. PLG and EDB thank the EPSRC and Johnson Matthey Plc for the award of studentships to MRW and MW. KY thanks the Japan Society for the Promotion of Science (JSPS) for a visiting Fellowship at the Nanocentre of University of York during the early part of the work and the Japan Fine Ceramic Center for the AC-Titan facility. The water gas shift (WGS) reaction, CO+H2O = CO2 + H2, is the basis of heterogeneous catalysis important in the generation of clean hydrogen energy for fuel cells, transportation fuels and in ammonia manufacture. Ceria supported gold and related nanoparticles are potentially viable catalysts for the low temperature WGS reaction. The WGS catalytic reaction is a dynamic process and takes place on the solid catalyst surface at the atomic level. The current understanding of the reaction is inferred from studies of static catalysts and from indirect chemical studies without single atom sensitivity. Therefore the nature of dynamic atomic processes in the WGS reaction has remained inaccessible. Since the catalyst reaction site and atomic processes by which it activates and deactivates, change both in magnitude and mechanism with the reaction environment it is of fundamental importance to visualise the dynamic catalyst at the atomic level in WGS (CO + water mixture) environments, in real time. Novel environmental (scanning) transmission electron microscope with singe atom resolution is used herein to directly visualise and characterise, in real time, evolving atomic structures and processes in practical gold/ceria catalysts in controlled WGS environments. The in-situ observations in WGS have revealed the formation of clusters of only a few gold atoms resulting from single atom dynamics and the catalytic effect of low coordination surface sites. The new insights have important implications for applications of nanoparticles in chemical process technologies including for transportation fuels and emission control. Postprint

Research has shown that transportation funding is a subject about which the public lacks a strong knowledge base. However, because of the complexity of the funding process, crafting outreach and educational materials that convey necessary information can be difficult. In 2014, researchers with the Texas A&M Transportation Institute conducted a series of 11 focus groups throughout Texas to test three transportation funding outreach and educational items. The research team found that by emphasizing that fuel taxes were excise fees and lost purchasing power over time and that reduced transportation funding led to greater reliance on debt, participants became more aware of transportation funding issues and showed greater interest in addressing them. Furthermore, showing participants what they actually paid in transportation fees and taxes increased their willingness to consider funding alternatives. The research team was also able to elicit greater interest in transportation funding issues by presenting information in relation to per-person costs and impacts and by discussing funding issues at a local–regional scale.

Electrolyte-soaked Nafion is commonly used as an ionic polymer in soft actuators. Here, a multi-technique investigation was applied to correlate the electrochemical behavior of Nafion membranes with their microstructures and nanostructures as a function of electrolyte type. The influence of electrolytes of Li salts with different counteranions on the Nafion membranes was investigated in terms of hydration level, structure (using X-ray diffraction and small angle X-ray scattering), stress–strain characteristics, and electrochemical behavior (by cyclic voltammetery and electrochemical impedance spectroscopy). The effects of using ionic liquid (IL), as the electrolyte, addition of different supporting solvent and the addition of Li+ ions to water-free IL-soaked membranes on the structural and electrochemical properties of Nafion were examined. The nano- and microstructure of the Nafion changed considerably as a function of the identity of the electrolyte solution. The electrochemical behavior of the IL-soaked samples was compared with that of the water-soaked Li+-exchanged Nafion. It was seen that the ionic conductivity of the Nafion membranes was reduced significantly when water was replaced by pure IL. Using the supporting solvents increased the conductivity of IL-soaked Nafion membranes dramatically. The presence of a small amount of Li+ ions together with the IL ions caused a significant decrease in charge transfer resistance and increases in double layer capacitance and in ionic conductivity over that of the water-free sample and also over water-soaked Li+-exchanged Nafion. These findings can be useful to improve the knowledge on Nafion's microstructure and also to improve the electromechanical behavior of Nafion-based ionic polymer–metal composites actuators. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45239.

We thank the University of St Andrews for the PhD scholarship of FS. Mesoporous carbon materials are of great interest as catalyst supports. However, the presence of impurities such as the metal or halide ions which are often used to catalyse the polymerisation and condensation reactions in their preparation can be poisonous to the final catalyst product. For this reason, in this work, metal- and halogen-free mesoporous polymer and carbon materials (OMCs) were synthesised using a modified two phase method employing alternative polymerisation and condensation catalysts. The OMC materials synthesised exhibit a highly ordered two dimensional hexagonal arrangement of cylindrical mesopores, as revealed by small angle XRD, gas physisorption and TEM analysis, and have typical specific surface areas of ca. 600 m2/g, pore size of ca. 7.0 nm, and pore volume of approximately 0.60 cm3/g. Their physical evolution with increasing calcination temperature is examined as are the effects of varying synthesis parameters on the nature of the final mesostructure. Postprint

The authors thank the University of Aberdeen for financial support. AuPd nanoparticles were prepared following a methodology designed to produce core-shell structures (Au core and Pd shell). Characterisation suggested slow addition of the shell metal favoured deposition onto the pre-formed core, whereas more rapid addition favoured the formation of a monometallic Pd phase in addition to some nanoparticles with core-shell morphology. When used for the selective hydrogenation of acetylene, samples which possessed monometallic Pd particles favoured over-hydrogenation to form ethane. A sample prepared by slow addition of a small amount of Pd resulted in the formation of a core-shell structure but with an incomplete Pd shell layer. This material exhibited completely different product selectivity with ethylene and oligomers forming as the major products as opposed to ethane. The improved performance was thought to be as a result of the absence of Pd particles which were capable of forming a Pd-hydride phase with enhanced oligomer selectivity associated with reaction on uncovered Au atoms. Postprint

In order to obtain different morphologies, nanostructured Gd 0.1 Ce 0.9 O 1.95 (GDC10) and Gd 0.2 Ce 0.8 O 1.90 (GDC20) were synthesized using three different chemical methods: reverse microemulsion (RM), cation complexation (CC) and template-filling (TF). The resulting materials were characterized by synchrotron radiation X-ray diffraction (SR-XRD), by X-ray absorption near-edge spectroscopy (XANES) and by scanning and high resolution transmission electron microscopy (SEM and HRTEM). All nanostructured mixed oxides were found to have a cubic crystal phase ( Fm3m space group) with an average crystallite sizes ranging from 9.6 to 13.2 nm. Tubular nanostructured GDC10 obtained using a template-filling method exhibited the largest specific surface area (97 m 2 g −1 ) while the lowest values were obtained using the cation complexation method (23 m 2 g −1 ). XANES results indicated that the extent of reduction of these materials was small. Nevertheless, the Ce 3+ ion was detected. Preliminary catalytic studies showed that the tubular nanostructured (TF) GDC10 samples exhibited better catalytic activity for CH 4 oxidation than the CC and RM nanopowders of the same chemical composition.

Ce x Zr 1− x O 2 mixed oxides nanopowders with x = 0.10, 0.25, 0.50, 0.75 and 0.90, and pure ceria, all prepared by a low temperature citrate complexion technique, were investigated using a range of temperature programmed (TP) techniques in order to evaluate their suitability for use as anode catalyst materials in solid oxide fuel cells operating on hydrocarbon fuels. In TP reduction experiments, reduction peak temperatures and peak areas were related to the activity and amount, respectively, of available catalyst oxygen. Mixed oxides with higher Ce contents ( x ≥ 0.50) were found to be reduced at significantly lower temperatures than samples with x x = 0.75 supplied the largest amount of labile oxygen. TP reaction experiments performed in dry methane on two samples indicated that susceptibility of the oxides to carbon deposition was inversely related to availability of catalyst oxygen. Light-off experiments in a stoichiometric CH 4 /O 2 mixture were performed to investigate the catalytic activity of the mixed oxide compositions for methane oxidation. Catalytic activity increased with cerium content to a maximum at x = 0.75 before decreasing at x = 0.90. All the mixed oxides were considerably more active for methane oxidation than pure CeO 2 prepared by the same citrate route.

A platinum catalyst with activated carbon-support (Pt/C) was prepared and showed a high activity for the deep gas-phase hydrodechlorination (HDC) of dichloromethane (DCM) and chloroform (TCM), with conversions of up to 70% and 100%, respectively (operating conditions: atmospheric pressure, reaction temperatures of 150–250 °C, and space–times of 0.08–1.7 kg h mol −1 ). The catalyst was highly selective to methane (the only non-chlorinated product) with selectivities of up to 85% for HDC of DCM and 93% for HDC of TCM. The catalyst showed exceptional stability with no loss of activity after 26 days on stream in the HDC of DCM. This can be ascribed to its high resistance to poisoning by organic compounds compared to Pd/C catalysts previously studied. This can be attributed to re-dispersion of Pt during the reaction and to the high proportion of metal in the zero-valent state (Pt 0 ) which disfavors the stabilization of chlorocarbon compounds at the active centers of the catalyst.

In a systematic study, Samarium doped ceria (SDC) nanopowders, Sm x Ce 1− x O 2− x /2 ( x = 0.1, 0.2 or 0.3), were prepared by a low temperature citrate complexation route. The synthesis and crystallisation of the SDC powders were followed by thermochemical techniques (TGA/DTA), X-ray diffraction, elemental analysis, specific surface area determination (BET) and electron microscopy (SEM and TEM). Mean crystallite sizes were found to be around 10 nm for all compositions calcined at 500 °C. Dense electrolyte bodies were prepared at 1300 °C, 1400 °C and 1450 °C using two sintering times, 4 h or 6 h. Densities of 91–97% of theoretical were obtained, with a marked improvement in density on going from 1300 °C to higher sintering temperatures. Grain size analysis was conducted using SEM. Grain size distributions were related to %Sm and sintering conditions. Impedance spectroscopy was used to determine the total, bulk and grain boundary conductivities, the related activation energies and enthalpies of defect association and ion migration. Sintering at 1400 °C/6 h or 1450 °C/4 h gave superior grain structure and conductivity, with oversintering occurring after more severe treatments. At 600 °C the highest total ionic conductivity was 1.81 × 10 −2 S cm −1 for Sm 0.2 Ce 0.8 O 1.9 . The relationships between chemical composition, sintering parameters, grain structure and electrochemical performance are discussed.

In this work, 1 wt % Pd/ZrO2−CeO2 mixed oxide nanotubes with 90 mol % CeO2 were synthesized following a very simple, high-yield procedure and their properties were characterized by synchrotron radiation X-ray diffraction, X-ray absorption near-edge spectroscopy (XANES), and scanning and high-resolution transmission electron microscopy (SEM and HRTEM). In situ XANES experiments were carried out under reducing conditions to investigate the reduction behavior of these novel nanotube materials. The Pd/CeO2-based nanotubes exhibited the cubic phase (Fm3m space group). The nanotube walls were composed of nanoparticles with an average crystallite size of about 7 nm, and the nanotubes exhibited a large specific surface area (85 m2·g−1). SEM and HRTEM studies showed that individual nanotubes were composed of a curved sheet of these nanoparticles. Elemental analysis showed that the Ce:Zr:Pd ratios appeared to be approximately constant across space, suggesting compositional homogeneity in the samples. XANES results ...

In the present work, a nanostructured Zr0.5Ce0.5O2 solid solution was synthesized using a citrate complexation technique with different thermal treatments. The resulting powders were characterized by employing X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). A qualitative analysis of the XRD data indicated that all samples exhibited a tetragonal phase (P42/nmc space group). In HRTEM observations, the internal crystal structure of the nanoparticles was studied and the primary particle sizes were measured. Average crystallite size, obtained from the XRD data using the Scherrer equation, ranged from 4.1 nm to 7.7 nm.

The Supergen fuel cell programme is the UK's flagship fuel cell research consortium, funded by the Research Councils. Established just under four years ago it brings together four academic partners (Imperial College, Newcastle University, Nottingham University and St Andrews University), three industry partners (Johnson Matthey, Rolls-Royce Fuel Cell systems and Ceres Power), and the UKs defence laboratory (DSTL), to work together to bring fundamental science to address key industry challenges in the fuel cell sector. This presentation will review progress made in tackling a number of key issues in solid oxide fuel cells, namely the constrained sintering of thick film electrolytes, electrolytes with higher conductivity at lower temperature, the relationship between fuel composition and anode behaviour - including work on sulphur poisoning and new anode materials, and new methods to characterize and model electrode performance.

The design of new anode materials to promote the reforming of methanol is important for the development of intermediate temperature direct methanol solid oxide fuel cells. A previous study showed Pd/CeO2−Sm2O3 to be a good candidate. Here, the influence of the calcination pretreatment of the support and the reduction temperature of the catalyst on the steam reforming of methanol are investigated, as they can become key factors in the performance of the catalyst. Conversion, H2 yield, and TOF were considerably higher when the support was calcined at 800 °C (Pd/CS-800) instead of 1000 °C (Pd/CS-1000). Characterization results suggest a stronger interaction of Pd particles with the support in Pd/CS-1000, which hinders its accessibility to the gas atmosphere, and a less homogeneous distribution of Pd particles. In both cases, the activity increases on increasing the reduction temperature from 400 to 500 °C. In addition, these catalysts were highly resistant to deactivation.

Catalysts of 2 wt % Pd supported on CeO2, Sm2O3, and CeO2/Sm2O3 (in a 4:1 molar ratio) were studied in detail by high-resolution transmission electron microscopy and elemental mapping, both as-prepared and after undergoing one of three reduction pretreatments of increasing severity. The evolution in the nanostructure, composition, and disposition of the phases were studied in detail as a function of starting composition and of pretreatment conditions. The trends observed were compared with the trends in activity and selectivity of the catalysts for hydrogen generation from methanol fuel, with a view to their application in direct methanol intermediate-temperature solid oxide fuel cells. The catalyst preparation conditions had a dramatic effect on the Sm-containing materials but not on the Pd/CeO2. The Pd/CeO2/Sm2O3 catalyst was seen to develop a beneficial hierarchical structure in which Pd particles were supported on fine Sm2O3 crystallites, which were in turn supported on larger CeO2 particles. This eff...

SrCe 0.95 Yb 0.05 O 3 (SCY) and related materials are under consideration as a proton conductors for Solid Oxide Fuel Cell (SOFC) electrolytes. Sintered pellets of SCY are used to perform impedance spectroscopy (IS) studies and fuel cell tests on cells with Pt electrodes of two different morphologies. Electrodes are applied to the SCY pellets by two routes: either by firing on a layer of Pt paint (denoted electrode P) or by magnetron sputtering (electrode S). In impedance spectra recorded over a wide temperature range under humidified hydrogen, in symmetrical cell conditions, cells with S electrodes give rise to a much smaller low frequency impedance feature than the cells with P electrodes. This is tentatively attributed to faster diffusion-related processes taking place at the S electrodes. The behaviour of working fuel cells with S and P electrode morphologies is evaluated in terms of maximum power output and Area Specific Resistance in two-atmosphere tests. The fuel cell anode with the S morphology results in superior fuel cell performance, in agreement with the impedance study. The influence of the two different electrode morphologies on the behaviour of the cells is discussed with reference to their morphology, as determined by SEM and AFM.

A variant of the sol–gel technique known as cation complexation is used to prepare a nanocrystalline Gd 0.1 Ce 0.9 O 1.95 (GDC) solid solution. A range of techniques including thermal analysis (TGA/DTA), X-ray diffraction, specific surface area determination (BET) and electron microscopy (SEM and TEM) are employed to characterise the GDC powders. GDC calcined at 500 °C is found to have an average crystallite size of 11 nm. Specific surface areas are found to be 29.7 m 2 g −1 for the as-calcined powder and 57.5 m 2 g −1 after ball milling at 400 rpm. Dense ceramic pellets are prepared from unmilled and ball-milled GDC powders employing different thermal treatments. Their electrical properties are studied by impedance spectroscopy. Those samples sintered at 1300 °C for 30 h (starting from ball-milled powders) exhibit the highest density (96% of theoretical density) and the highest total ionic conductivity (1.91 × 10 −2 S cm −1 at 600 °C).

In this research, interviews and survey data were used to understand better the truckers’ use of toll roads. On the basis of interviews with industry representatives, shipping companies, and drivers, it was clear that owner–operators were the least likely to use toll roads because of the difficulty in passing the cost of the toll on to their customers. Company-owned shipping operations were the most likely to analyze the potential benefits of a toll route carefully and possibly to use that route. A survey of truck drivers in the Austin, Texas, area was conducted both online and by paper. The survey's focus was on the use of State Highway (SH) 130, a tolled bypass route around Austin, versus the use of I-35, which runs through Austin. More than 2,000 respondents indicated their preferred route and whether certain incentives would motivate them to use SH-130. The survey results mirrored the results from the interviews, with smaller companies (owner–operators) preferring the nontoll route. The incentives that most interested the truckers were off-peak discounts, followed by the incentive of a free trip after a number of paid trips. The average value of travel time savings was $44.20/h.

In this work, ZrO2−CeO2 mixed oxide nanotubes with 50, 70, and 90 mol % CeO2 were synthesized following a very simple, high yield procedure, and their properties were characterized by synchrotron radiation XRD and by high resolution electron microscopy. The 50, 70, and 90 mol % CeO2 nanotubes exhibited the tetragonal phase (t′-form and t′′-form, P42/nmc space group) or the cubic phase (Fm3m space group). The nanotube walls were composed of nanoparticles with an average crystallite size ranging from 4.7 to 7.6 nm. Electron microscopy observations confirmed the size of these nanoparticles by direct observation. The SEM and TEM results showed that individual nanotubes were composed of a curved sheet of these nanoparticles. By SEM analysis, the nanotubes were found to have lengths of around 1−8 μm, diameters of around 500 nm, and wall thicknesses of 20 nm. Elemental analysis showed that Ce:Zr ratios appeared to be constant across space, suggesting compositional homogeneity in the samples. The 90 mol % CeO2 na...

To develop the proton exchange membrane water electrolyzer (PEMWE) with satisfactory performance and durability for application in a regenerative fuel cell (RFC) system, anode electrocatalysts of Ir, Ru and their oxides were prepared and incorporated into the catalyst coated membranes (CCM) of the PEMWE. Repetitive cyclic voltammetry of the Nafion bonded electrodes, steady state polarization curves and stability testing of the single PEMWE cells were performed to investigate the performance and stability of these electrocatalysts. The structure and specific surface areas of the electrocatalysts were characterized by XRD and BET. IrO 2 exhibited a slightly lower performance but a markedly higher stability than the other electrocatalysts. By modifying the preparation process via a colloidal iridium hydroxide hydrate precursor, which permitted a lower heat treatment temperature, its performance was enhanced, corresponding to a terminal voltage of 1.63 V at 1 A/cm 2 .

In this work, a variant of the sol–gel technique known as cation complexation was used for the preparation of Gadolinum-doped ceria (GDC) solid solution. This method has the advantage of low cost and relative simplicity. A range of techniques including X-ray diffraction (XRD), specific surface area determination (BET) and scanning electron microscopy (SEM) were employed to characterize the GDC powder. GDC calcined at 500 ∘ C was found to have an average crystallite size of 10 nm. To obtain an insight into any changes in the electrolyte material during operation, the electrochemical properties of dense GDC samples were studied by impedance spectroscopy (IS) before and after simple ageing treatment in dry air at 800 ∘ C for 40 h. A reduction in grain boundary conductivity was observed after thermal treatment in the sample with the lower density.

Soft actuators are of great technological interest and one class of these is made from ionic polymer-metal composites (IPMCs). It has been established that replacement of water with an ionic liquid (IL) in IPMCs results in larger actuation response and considerably longer operating life. However, the rate of displacement of IL-based IPMCs is very low. In the current work, IPMC actuators were fabricated using Nafion membrane and an imidazolium-based IL. The effects of incorporating the IL with and without Li+ ions were followed using electromechanical and electrochemical measurements and were compared with the corresponding behavior of water-based Li+-exchanged and un-exchanged IPMC actuators. The addition of Li+ ions to the IL-based system resulted in dramatic increases in the capacitance, ionic conduction, operating life and in the displacement rate of the actuator. This strategy is of considerable interest for enabling the use of IPMC-based soft actuators in medicine and robotics. Postprint

This work was conducted under the aegis of the Engineering and Physical Sciences Research Council (EPSRC) of the United Kingdom (EP/I004173/1). Amin Abdolvand is an EPSRC Career Acceleration Fellow at the University of Dundee. In order to enable exploitation of noble metal/poly(vinyl-alcohol) nanocomposites for device fabrication, solutions of poly(vinyl-alcohol) suitable for piezo-driven inkjet printing techniques are identified and discussed in terms of their material properties. The printable poly(vinyl-alcohol) medium is then exploited as a host material through the formation of silver or gold nanoparticles in order to create nanocomposites that exhibit a surface plasmon resonance behaviour associated with the small metallic inclusions. To mitigate some of the material redistribution effects associated with the drying of printed droplets containing finely divided materials, the metallic nanoparticles are formed after the printing and drying process is completed, by way of an in-situ reduction of an appropriate metal salt by the poly(vinyl-alcohol)-host matrix itself, which takes place at modest temperatures compatible with most substrate materials. An obvious application for such nanocomposites is in optical elements whereby the surface plasmon resonance associated with the metal is the functional aspect of devices such as sensors or active optical elements. High Resolution Transmission Electron Microscopy was used to examine the dimensions, distribution, morphology and crystal structure of the silver and gold nanoparticles in detail allowing discussion of their suitability for these applications and what further optimisation may be necessary to adequately control their formation. Publisher PDF

In this work, nanostructured Ce1−xTbxO2−δ (x = 0.1 and 0.2) spheres were synthesized by microwave assisted hydrothermal homogeneous co-precipitation and their properties were characterized by synchrotron radiation X-ray diffraction (SR-XRD), X-ray absorption spectroscopy (XAS) and scanning and high resolution electron microscopy (SEM and HRTEM) with energy dispersive X-ray spectroscopy (EDS). Spherical particles with average diameters around 200 nm were obtained in excellent yields. In order to compare the effect of the morphology on the physico-chemical properties, terbium-doped ceria nanopowders were also synthesized by a cation complexation method. In situ SR-XRD, X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) experiments were carried out under reducing and oxidizing conditions in order to investigate the redox behaviour of these materials and to evaluate the oxidation state ratios in the Ce3+/Ce4+ and Tb3+/Tb4+ couples. All of the Ce1−xTbxO2−δ samples were found to have a cubic crystal structure (Fm[3 with combining macron]m space group). The spheres were composed of nanoparticles with an average crystallite size of about 10 nm. In situ XRD experiments showed an increase in lattice parameters on reduction which was attributed to the reduction of Ce4+ and Tb4+ cations to Ce3+ and Tb3+, which have larger radii, and to the associated increase in the VO concentration. The effect of the synthesis method on structural properties was evident in that the percentage of Tb present as Tb3+ in the nanostructured spheres was larger than that in the nanopowders of the same elemental composition. Fil: Acuña, Leandro Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas de las Fuerzas Armadas. Centro de Investigaciones en Sólidos; Argentina Fil: Muñoz, Fernando Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas de las Fuerzas Armadas. Centro de Investigaciones en Sólidos; Argentina Fil: Albornoz, Cecilia Andrea. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina Fil: Leyva de Guglielmino, Ana Gabriela. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina Fil: Baker, Richard. University of St. Andrews; Reino Unido Fil: Fuentes, Rodolfo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina