نتایج جستجو برای: sulfur s t
تعداد نتایج: 1332969 فیلتر نتایج به سال:
Graphene-sulfur composites with sulfur fractions as high as 87 wt% are prepared using a simple one-pot, scalable method. The graphene envelops the sulfur particles, providing a conductive shrink-wrap for electron transport. These materials are efficient cathodes for Li-S batteries, yielding 93% coulombic efficiency over 50 cycles with good capacity.
At present, the most promising alternative cathode material is sulfur due to its high theoretical capacity (1672 mAh g −1 ), low cost, high abundance in nature, and environmental benignity. [ 11–13 ] However, the rechargeable battery chemistry based on sulfur cathode still faces three intrinsic challenges: [ 14–19 ] (1) the formation of intermediate polysulfi de products and the parasitic shutt...
Carbon materials that are intrinsically co-doped with nitrogen and sulfur heteroatoms are synthesised by facile annealing of nitrile-functionalised thiazolium salts. Extremely high degrees of doping are achieved, especially for sulfur. The method further allows for direct tuning of the amounts of both N and S, establishing a new synthetic pathway in the emerging field of S-doped carbon materials.
This work explores surface changes and the Hg capture performance of brominated activated carbon (AC) pellets, sulfur-treated AC pellets, and sulfur-treated AC fibers upon exposure to simulated Powder River Basin-fired flue gas. Hg breakthrough curves yielded specific Hg capture amounts by means of the breakthrough shapes and times for the three samples. The brominated AC pellets showed a sharp...
The cysteine desulfurase IscS is a highly conserved master enzyme initiating sulfur transfer via persulfide to a range of acceptor proteins involved in Fe-S cluster assembly, tRNA modifications, and sulfur-containing cofactor biosynthesis. Several IscS-interacting partners including IscU, a scaffold for Fe-S cluster assembly; TusA, the first member of a sulfur relay leading to sulfur incorporat...
Porous spherical carbons (PSCs) with tunable pore structure (pore volume, pore size, and surface area) were prepared by an aerosol-assisted process. PSC/sulfur composites (PSC/S, S: ca.59 wt %) were then made and characterized as cathodes in lithium/sulfur batteries. The relationships between the electrochemical performance of PSC/S composites and their pore structure and particle morphology we...
Evidence from several fields of investigation lead to the hypothesis that the sulfur atom is involved in vitamin B12-dependent methyl group transfer. To compile the evidence, it is necessary to briefly review the following fields: methylation, the new field of sulfane sulfur/hydrogen sulfide (S°/H₂S), hydrosulfide derivatives of cobalamins, autoxidation of hydrosulfide radical, radical S-adenos...
A novel nitrogen doped mesoporous carbon (NMPC) with a hierarchical porous structure is prepared by simple carbonizing the green algae, which is applied as a host material to encapsulate sulfur for lithium/sulfur (Li/S) battery. The NMPC exhibits high pore volume as well as large specific surface area, and thus sulfur content in the S/NMPC composite reaches up to 63 wt %. When tested in a Li/S ...
Lithium-sulfur (Li-S) battery is a promising high energy storage candidate in electric vehicles. However, the commonly employed ether based electrolyte does not enable to realize safe high-temperature Li-S batteries due to the low boiling and flash temperatures. Traditional carbonate based electrolyte obtains safe physical properties at high temperature but does not complete reversible electroc...
A novel purple sulfur bacterium, strain WS(T), was isolated from a microbial mat from an estuary of the White Sea. Individual cells are coccoid shaped, motile by flagella and do not contain gas vesicles. The mean cell diameter is 1.85 mum (range 1.5-2.0 mum). Cell suspensions exhibit a purple-violet colour. They contain bacteriochlorophyll a and carotenoids of the rhodopinal series as photosynt...
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