This paper covers the optimization of methane volumetric storage capacity by controlling the sub-nanometre (<1 nm) and supra-nanometre (1–5 nm) pore volumes. Nanospace engineering of KOH activated carbon generates an ideal structure for methane storage in which gas molecules are adsorbed as a high-density fluid by strong van der Waals forces into pores that are a few molecules in diameter. High specific surface areas, porosities, sub-nanometre (<1 nm) and supra-nanometre (1–5 nm) pore volumes are quantitatively selected by controlling the degree of carbon consumption and metallic potassium intercalation into the carbon lattice during the activation process. The formation of tuneable sub-nanometre and supra-nanometre pores is validated by sub-critical nitrogen adsorption. Aberration-corrected scanning transmission electron microscopy data show the atomic structure of high-surface-area activated carbon (2600 m2/g). While high surface area and high porosity are optimal for gravimetric methane storage, the results indicate that an exclusive sub-nanometre region, a low porosity and an acceptable surface area (approximately 2000 m2/g) are ideal for methane volumetric storage, storing 120 g CH4/l (184 vol/vol) at 35 bar and room temperature (22 °C). High-pressure methane isotherms up to 150 bar at 30, −25 and −50 °C on optimal activated carbons are presented. Methane volumetric storage capacity at 35 bar reaches 176 g/l (269 vol/vol) and 202 g/l (309 vol/vol) at −25 and −50 °C, respectively.

Despite extensive recent research efforts on material-specific peptides, the fundamental problem to be explored yet is the molecular interactions between peptides and inorganic surfaces. Here we used computer simulations (density functional theory and classical molecular dynamics) to investigate the adsorption mechanism of silicon-binding peptides and the role of individual amino acids in the affinity of peptides for an n-type silicon (n+-Si) semiconductor. Three silicon binding 12-mer peptides previously elaborated using phage display technology have been studied. The peptides' conformations close to the surface have been determined and the best-binding amino acids have been identified. Adsorption energy calculations explain the experimentally observed different degrees of affinity of the peptides for n+-Si. Our residual scanning analysis demonstrates that the binding affinity relies on both the identity of the amino acid and its location in the peptide sequence.

One of potential perspectives for clean fueling of cars is the use of hydrogen-powered fuel cells. A major challenge in the massif implementation of hydro-gen-fuelled vehicles still consist in designing hydrogen storage systems that are reversible, light, cheap and able of delivering a driving range of few hundreds of kilometers. Between the possible hydrogen adsorbents carbon porous structures with locally slit-shaped pore geometry remain the most promising ones.It has been shown in the past that it is not possible to increase hydrogen storage capacity by modification of slit width only, without simultaneous in-crease of the specific surface. Here, we propose new models of hypothetical all-carbon with specific surfaces higher than that of graphene. We call them Open Carbon Frameworks, OCF (Fig.1). The structures are ordered, and have low density architecture required for effective applications for mobile storage. Theoretically they may have the specific surfaces exceeding 6000 m2/g. From the analysis of the computer simulations of adsorption properties of the new structures, a rich spectrum of relations between structural characteristics of OCFs and ensuing hydrogen adsorption (structure-function relations) emerg-es: (i) storage capacities higher than in slit-shaped pores can be obtained by fragmentation/truncation of graphene sheets, which creates additional surface areas (with respect to infinite graphene sheets), carried mainly by edge sites; ii) for OCFs with a ratio of in-plane to edge sites approximately equal 1 and sur-face areas of 3800-6500 m2/g, we found at 77 K record maximum excess ad-sorption of 75-85 g H2/kg C, and record storage capacity of 100-260 g H2/kg C (at 100 bar); (iii) additional increase of hydrogen uptake could potentially be achieved by chemical substitution and/or intercalation of OCF structures, in or-der to increase the energy of adsorption. In consequence we conclude that OCF structures, if synthesized, will allow the hydrogen uptake at the level re-quired for vehicular applications.

pas d'abstract

Engineering shape-controlled bionanomaterials requires comprehensive understanding of interactions between biomolecules and inorganic surfaces. We explore the origin of facet-selective binding of peptides adsorbed onto Pt(100) and Pt(111) crystallographic planes. Using molecular dynamics simulations, we show that upon adsorption the peptides adopt a predictable conformation. We compute the binding energies of the amino acids constituting two adhesion peptides for Pt, S7, and T7 and demonstrate that peptides' surface recognition behavior that makes them unique among populations originates from differential adsorption of their building blocks. We find that the degree of peptide binding is mainly due to polar amino acids and the molecular architecture of the peptides close to the Pt facets. Our analysis is a first step in the prediction of enhanced affinity between inorganic materials and a peptides, toward the synthesis of novel nanomaterials with programmable shape, structure, and properties.