Alternative fuels are essential to enable the transition to a sustainable and environmentally friendly energy supply. Synthetic fuels derived from renewable energies can act as energy storage media, thus mitigating the effects of fossil fuels on environment and health. Their economic viability, environmental impact, and compatibility with current infrastructure and technologies are fuel and power source specific. Nitrogen-based fuels pose one possible synthetic fuel pathway. In this review, we discuss the progress and current research on utilization of nitrogen-based fuels in power applications, covering the complete fuel cycle. We cover the production, distribution, and storage of nitrogen-based fuels. We assess much of the existing literature on the reactions involved in the ammonia to nitrogen atom pathway in nitrogen-based fuel combustion. Furthermore, we discuss nitrogen-based fuel applications ranging from combustion engines to gas turbines, as well as their exploitation by suggested end-uses. Thereby, we evaluate the potential opportunities and challenges of expanding the role of nitrogen-based molecules in the energy sector, outlining their use as energy carriers in relevant fields.
Ceramic Fe-Al-O nanofibers with a core-shell architecture were obtained by electrospinning. The fibers consist of an Fe-Al-O core with novel lamellar-like mesopores and an Fe-rich shell. A mechanism of this unique core and shell formation is outlined and confirmed. The described mesoporous nanofibers are highly promising for new research and applications involving catalysis, sensing and absorption of mobile components on the accessible porous core surface.
Ceramic nanobelt
catalysts consisting of Fe–Al–O
spinel modified with potassium were synthesized for CO2 hydrogenation into hydrocarbons. Nanobelts and hollow nanofibers
were produced utilizing the internal heat released by oxidation of
the organic component within the fibers. This extremely fast and short
heating facilitated crystallization of the desired phase, while maintaining
small grains and a large surface area. We investigated the effects
of mat thickness, composition, and heating rate on the final morphology.
A general transformation mechanism for electrospun nanofibers that
correlates for the first time the mat’s thickness and the rate
of oxidation during thermal treatment was proposed. The catalytic
performance of carburized ceramic K/Fe–Al–O nanobelts
was compared to the K/Fe–Al–O spinel powder. The electrospun
catalyst showed a superior carbon dioxide conversion of 48% and a
selectivity of 52% to light C2–C5 olefins,
while the powder catalyst produced mainly C6
+ hydrocarbons. Characterization of steady state catalytic materials
by energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray
photoelectron spectroscopy, high-resolution transmission electron
microscopy, and N2-adsorption methods revealed that high
olefin selectivity of the electrospun materials is related to a high
extent of reduction of surface iron atoms because of more efficient
interaction with the potassium promoter.
Controlling polymorphism in molecular crystals is crucial in the pharmaceutical, dye, and pesticide industries. However, its theoretical description is extremely challenging, due to the associated long time scales (>1 μs). We present an efficient procedure for identifying collective variables that promote transitions between conformational polymorphs in molecular dynamics simulations. It involves applying a simple dimensionality reduction algorithm to data from short (∼ps) simulations of the isolated conformers that correspond to each polymorph. We demonstrate the utility of our method in the challenging case of the important energetic material, CL-20, which has three anhydrous conformational polymorphs at ambient pressure. Using these collective variables in Metadynamics simulations, we observe transitions between all solid polymorphs in the biased trajectories. We reconstruct the free energy surface and identify previously unknown defect and intermediate forms in the transition from one known polymorph to another. Our method provides insights into complex conformational polymorphic transitions of flexible molecular crystals.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.