This study evaluated the catalytic activity of Mo catalysts derived from hydrotalcite-like compounds for steam reforming of toluene as a model compound for tar. The catalysts with 1.5, 3 and 4.5 Mo loadings (wt%), denoted as Mo1.5MgAl, Mo3MgAl and Mo4.5MgAl respectively, were prepared by coprecipitation and characterized by BET, XRD, SEM, TEM, FT-IR and UV–VIS. The results showed that toluene conversion increased with increasing molybdenum content. The hydrogen amount depended on two factors: the presence of molybdate species on the surface and the presence of aluminum cations in tetrahedral sites (Mo3MgAl), with molybdenum influence being more pronounced. The H2/CO ratio decreased at increasing temperature while, the H2/CO2 ratio increased proportionally with temperature. Mo1.5MgAl catalyst was more selective for CO2 and H2, while, Mo3MgAl and Mo4.5MgAl were more selective for CO and H2.

Coatings of hierarchically meso-macroporous antimony-doped tin oxide (ATO) enable interfacing adsorbed species, such as biomacromolecules, with an electronic circuit. The coating thickness is a limiting factor for the surface coverage of adsorbates, that are electrochemically addressable. To overcome this challenge, a carbon black-based templating method was developed by studying the composition of the template system, and finding the right conditions for self-standing templates, preventing the reaction mixture from flowing out of the mask. The thicknesses of as-fabricated coatings were measured using stylus profilometry to establish a relationship between the mask thickness and the coating thickness. Cyclic voltammetry was performed on coatings with adsorbed cytochrome c to check whether the entire coating thickness was electrochemically addressable. Further, bacterial photosynthetic reaction centers were incorporated into the coatings, and photocurrent with respect to coating thickness was studied. The template mixture required enough of both carbon black and polymer, roughly 7% carbon black and 6% poly(ethylene glycol). Coatings were fabricated with thicknesses approaching 30 µm, and thickness was shown to be controllable up to at least 15 µm. Under the experimental conditions, photocurrent was found to increase linearly with the coating thickness, up to around 12 µm, above which were diminished gains.

Housing bio-nano guest devices based on DNA nanostructures within porous, conducting, inorganic host materials promise valuable applications in solar energy conversion, chemical catalysis, and analyte sensing. Herein, we report a single-template synthetic development of hierarchically porous, transparent conductive metal oxide coatings whose pores are freely accessible by large biomacromolecules. Their hierarchal pore structure is bimodal with a larger number of closely packed open macropores (∼200 nm) at the higher rank and with the remaining space being filled with a gel network of antimony-doped tin oxide (ATO) nanoparticles that is highly porous with a broad size range of textual pores mainly from 20-100 nm at the lower rank. The employed carbon black template not only creates the large open macropores but also retains the highly structured gel network as holey pore walls. Single molecule fluorescence microscopic studies with fluorophore-labeled DNA nanotweezers reveal a detailed view of multimodal diffusion dynamics of the biomacromolecules inside the hierarchically porous structure. Two diffusion constants were parsed from trajectory analyses that were attributed to free diffusion (diffusion constant D = 2.2 μm2/s) and to diffusion within an average confinement length of 210 nm (D = 0.12 μm2/s), consistent with the average macropore size of the coating. Despite its holey nature, the ATO gel network acts as an efficient barrier to the diffusion of the DNA nanostructures, which is strongly indicative of physical interactions between the molecules and the pore nanostructure.

NASICON-type materials with general formula A(x)M(2)(PO4)(3) (A = Li or Na, M = Ti, V, and Fe) are promising candidates for Li-and Na-ion batteries due to their open three-dimensional framework structure. Here we report the electrochemical properties of hydrogen titanium phosphate sulfate, HoATi(2)(PO4)(2.4)(SO4)(0.6) (HTPS), a new mixed polyanion material with NASICON structure. Micron-sized HTPS aggregates with crystallite grain size of ca. 23 nm are synthesized using a sol-gel synthesis in an acidic medium. The properties of the as-synthesized HTPS, ball-milled HTPS, and samples prepared as carbon composites using an in-situ glucose decomposition reaction are investigated. A capacity of 148 mAh r1 corresponding to insertion of 2 Li+ per formula unit is observed in the ball-milled HTPS over the potential window of 1.5-3.4 V vs. Li/Li+. Lithiation at ca. 2.8 and 2.5 V is determined to occur through filling of the M1 and M2 sites, respectively. Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) are used characterize the HTPS before and after cycling. Evaluation of the HIPS in a Na-ion cell is also performed. A discharge capacity of 93 mAh g(-1) with sodiation at ca. 2.9 and 2.2 V vs. Na/Na+ is observed.(C) 2017 Elsevier B.V. All rights reserved.

The steam reforming of toluene has been studied on three catalysts with vanadium (0.9, 1.75, 3%) derived from hydrotalcites precursors (Mg/Al molar ratio 3) in the temperature range 400-500 degrees C. Catalysts were characterized by BET, XRD, SEM, TEM, FT-IR and then a correlation between physico-chemical characteristics and catalytic activity for toluene steam reforming has been done. The results showed that the catalyst with 3% V, with polyvanadate species, achieves the best catalytic activity, with a toluene conversion of 77.5%, at 500 degrees C, and a H-2 composition of 57%. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

The conversion of alcohols towards aldehydes in the presence of catalysts by non-oxidative dehydrogenation requires special importance from the perspective of green chemistry. Sodium (Na) super ionic conductor (NASICON)-type hydrogen titanium phosphate sulfate (HTPS; H1−xTi2(PO4)3−x(SO4)x, x = 0.5–1) catalysts were synthesized by the sol-gel method, characterized by N2 gas sorption, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), NH3 temperature-programmed desorption (NH3-TPD), ultraviolet–visible (UV-VIS) spectroscopy, and their catalytic properties were studied for the non-oxidative dehydrogenation of methanol and ethanol. The ethanol is more reactive than methanol, with the conversion for ethanol exceeding 95% as compared to methanol, where the conversion has a maximum value at 55%. The selectivity to formaldehyde is almost 100% in methanol conversion, while the selectivity to acetaldehyde decreases from 56% to 43% in ethanol conversion, when the reaction temperature is increased from 250 to 400 °C.

Journal Article FIB milling of polymer ceramic nanocomposites: far-reaching thermal artefacts and application to analysis of corrosion barrier coatings Get access Konrad Rykaczewski, Konrad Rykaczewski School for Engineering of Transport, Matter and Energy, Arizona State University, Tempe, AZ, US Search for other works by this author on: Oxford Academic Google Scholar Daniel G Mieritz, Daniel G Mieritz Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, US Search for other works by this author on: Oxford Academic Google Scholar Minglu Liu, Minglu Liu School for Engineering of Transport, Matter and Energy, Arizona State University, Tempe, AZ, US Search for other works by this author on: Oxford Academic Google Scholar Yuanyu Ma, Yuanyu Ma School for Engineering of Transport, Matter and Energy, Arizona State University, Tempe, AZ, US Search for other works by this author on: Oxford Academic Google Scholar Erick B Iezzi, Erick B Iezzi Naval Research Laboratory, Chemistry Division, Washington, DC, US Search for other works by this author on: Oxford Academic Google Scholar Xiaoda Sun, Xiaoda Sun School for Engineering of Transport, Matter and Energy, Arizona State University, Tempe, AZ, US Search for other works by this author on: Oxford Academic Google Scholar Liping P Wang, Liping P Wang School for Engineering of Transport, Matter and Energy, Arizona State University, Tempe, AZ, US Search for other works by this author on: Oxford Academic Google Scholar Kiran N Solanki, Kiran N Solanki School for Engineering of Transport, Matter and Energy, Arizona State University, Tempe, AZ, US Search for other works by this author on: Oxford Academic Google Scholar Don K Seo, Don K Seo Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, US Search for other works by this author on: Oxford Academic Google Scholar Robert Y Wang Robert Y Wang School for Engineering of Transport, Matter and Energy, Arizona State University, Tempe, AZ, US Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 22, Issue S3, 1 July 2016, Pages 142–143, https://doi.org/10.1017/S1431927616001562 Published: 25 July 2016

The ability to exchange energy and information between biological and electronic materials is critical in the development of hybrid electronic systems in biomedicine, environmental sensing, and energy applications. While sensor technology has been extensively developed to collect detailed molecular information, less work has been done on systems that can specifically modulate the chemistry of the environment with temporal and spatial control. The bacterial photosynthetic reaction center represents an ideal photonic component of such a system in that it is capable of modifying local chemistry via light-driven redox reactions with quantitative control over reaction rates and has inherent spectroscopic probes for monitoring function. Here a well-characterized model system is presented, consisting of a transparent, porous electrode (antimony-doped tin oxide) which is electrochemically coupled to the reaction center via a cytochrome c molecule. Upon illumination, the reaction center performs the 2-step, 2-electron reduction of a ubiquinone derivative which exchanges with oxidized quinone in solution. Electrons from the electrode then move through the cytochrome to reoxidize the reaction center electron donor. The result is a facile platform for performing redox chemistry that can be optically and electronically controlled in time and space.

By the establishment of highly controllable synthetic routes, electronic band-edge energies of the n-type transparent semiconductor Zr-doped anatase TiO2 have been studied holistically for the first time up to 30 atom % Zr, employing powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen gas sorption measurements, UV/vis spectroscopies, and Mott-Schottky measurements. The materials were produced through a sol-gel synthetic procedure that ensures good compositional homogeneity of the materials, while introducing nanoporosity in the structure, by achieving a mild calcination condition. Vegard's law was discovered among the homogeneous samples, and correlations were established between the chemical compositions and optical and electronic properties of the materials. Up to 20% Zr doping, the optical energy gap increases to 3.29 eV (vs 3.19 eV for TiO2), and the absolute conduction band-edge energy increases to -3.90 eV (vs -4.14 eV). The energy changes of the conduction band edge are more drastic than what is expected from the average electronegativities of the compounds, which may be due to the unnatural coordination environment around Zr in the anatase phase.

We report a direct sol–gel synthesis and characterization of new proton-containing, rhombohedral NASICION-type titanium compounds with mixed phosphate and sulfate oxoanions. The synthetic conditions were established by utilizing peroxide ion as a decomposable and stabilizing ligand for titanyl ions in the presence of phosphates in a strong acidic medium. Thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), induction-coupled plasma optical emission spectroscopic (ICP-OES) elemental analysis, and Raman and 1H magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopic studies have determined the presence of sulfate and proton ions in the structure, for which the compositional range has been found to be H1−xTi2(PO4)3−x(SO4)x (x=0.5–1). The particulate products exhibit a nanocrystalline nature observed through characterization with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The N2 sorption isotherm measurements and subsequent Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) analyses confirmed the presence of the textural meso- and macropores in the materials. Future studies would determine the potential of the new compounds in various applications as battery materials, proton conductors and solid acid catalysts.

The Ti 4+ :PO 4 3- ratio (1.0—1.5) and the calcination temperature (400—750 °C) are systematically varied in the preparation of the title NASICON-type compounds.

Summary Focused ion beam and scanning electron microscope (FIB‐SEM) instruments are extensively used to characterize nanoscale composition of composite materials, however, their application to analysis of organic corrosion barrier coatings has been limited. The primary concern that arises with use of FIB to mill organic materials is the possibility of severe thermal damage that occurs in close proximity to the ion beam impact. Recent research has shown that such localized artefacts can be mitigated for a number of polymers through cryogenic cooling of the sample as well as low current milling and intelligent ion beam control. Here we report unexpected nonlocalized artefacts that occur during FIB milling of composite organic coatings with pigment particles. Specifically, we show that FIB milling of pigmented polysiloxane coating can lead to formation of multiple microscopic voids within the substrate as far as 5 μm away from the ion beam impact. We use further experimentation and modelling to show that void formation occurs via ion beam heating of the pigment particles that leads to decomposition and vaporization of the surrounding polysiloxane. We also identify FIB milling conditions that mitigate this issue.

Alumina-supported molybdena–ceria catalysts were prepared by a sol–gel method and characterized by X-ray diffraction, N2 sorptometry, UV-vis-NIR diffuse reflectance spectroscopy, SEM and TEM.

The glycerol steam reforming was investigated on alumina supported molybdena catalysts (with 2, 5 and 12wt.%) prepared by the sol–gel method and gel combustion. The catalysts were characterized by XRD, BET, UV–VIS, DRIFT, SEM and TEM. The catalytic performances were studied at 400–500°C, steam to glycerol molar ratio between 9:1 and 20:1 and feed flow rate 0.04–0.08ml/min. The conversion is directly proportional to molybdena loading, while the hydrogen selectivity has reached greater value on catalyst with 2% MoO3. The optimum ratio steam to glycerol for reforming is 15:1 and for decomposition in syngas 9:1 and the ratio 20:1 favors water gas shift reaction.