Among the carbon allotropes, carbyne chains appear outstandingly accessible for sorption and very light. Hydrogen adsorption on calcium-decorated carbyne chain was studied using ab initio density functional calculations. The estimation of surface area of carbyne gives the value four times larger than that of graphene, which makes carbyne attractive as a storage scaffold medium. Furthermore, calculations show that a Ca-decorated carbyne can adsorb up to 6 H(2) molecules per Ca atom with a binding energy of ∼0.2 eV, desirable for reversible storage, and the hydrogen storage capacity can exceed ∼8 wt %. Unlike recently reported transition metal-decorated carbon nanostructures, which suffer from the metal clustering diminishing the storage capacity, the clustering of Ca atoms on carbyne is energetically unfavorable. Thermodynamics of adsorption of H(2) molecules on the Ca atom was also investigated using equilibrium grand partition function.

. (2016) Direct fabrication of functional ultrathin single-crystal nanowires from quasi-one-dimensional van der Waals crystals. Nano Letters. Permanent WRAP URL:http://wrap.warwick.ac.uk/81687 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher's statement:"This document is the Accepted Manuscript version of a Published Work that appeared in final form in Nano Letters copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work http://pubs.acs.org/page/policy/articlesonrequest/index.html ." A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP URL above for details on accessing the published version and note that access may require a subscription. A functional logic gate consisting of both n-type Ta2Pd3Se8 and p-type Ta2Pt3Se8 field-effect

Electrocatalytic hydrogen evolution reaction (HER) in alkaline solution is hindered by its sluggish kinetics toward water dissociation. Nickel-based catalysts, as low-cost and effective candidates, show great potentials to replace platinum (Pt)-based materials in the alkaline media. The main challenge regarding this type of catalysts is their relatively poor durability. In this work, we conceive and construct a charge-polarized carbon layer derived from carbon quantum dots (CQDs) on NiN nanostructure (NiN@CQDs) surfaces, which simultaneously exhibit durable and enhanced catalytic activity. The NiN@CQDs shows an overpotential of 69 mV at a current density of 10 mA cm in a 1 M KOH aqueous solution, lower than that of Pt electrode (116 mV) at the same conditions. Density functional theory (DFT) simulations reveal that NiN and interfacial oxygen polarize charge distributions between originally equal C-C bonds in CQDs. The partially negatively charged C sites become effective catalytic centers for the key water dissociation step via the formation of new C-H bond (Volmer step) and thus boost the HER activity. Furthermore, the coated carbon is also found to protect interior NiN from oxidization/hydroxylation and therefore guarantees its durability. This work provides a practical design of robust and durable HER electrocatalysts based on nonprecious metals.

We propose a new way to produce high-quality films of diamond from chemically functionalized few-layer graphene. Our ab initio calculations show that depending on functionalization few-layer graphene may convert spontaneously in a welldefined way to either cubic or hexagonal diamond films with a specific surface and welldefined properties. We provide specific results for the converting process using H, H 2 , F, F 2 , H 2 O, and NH 3 as adsorbates at different temperatures and pressures.