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Abstract: Rapid motion of electrolyte ions is a crucial requirement to ensure the fast charging/discharging and the high power densities of supercapacitor devices. This motion is primarily determined by the pore size and connectivity of the used porous carbon electrodes. Here, the diffusion characteristics of each individual electrolyte component, that is, anion, cation, and solvent confined to model carbons with uniform and well‐defined pore sizes are quantified. As a result, the contributions of micropores, mesopores, and hierarchical pore architectures to the overall transport of adsorbed mobile species are rationalized. Unexpectedly, it is observed that the presence of a network of mesopores, in addition to smaller micropores—the concept widely used in heterogeneous catalysis to promote diffusion of sorbates—does not necessarily enhance ionic transport in carbon materials. The observed phenomenon is explained by the stripping off the surrounding solvent shell from the electrolyte ions entering the micropores of the hierarchical material, and the resulting enrichment of solvent molecules preferably in the mesopores. It is believed that the presented findings serve to provide fundamental understanding of the mechanisms of electrolyte diffusion in carbon materials and depict a quantitative platform for the future designing of supercapacitor electrodes on a rational basis. [ABSTRACT FROM AUTHOR]

This study elucidates an innovative mechanochemical approach applying Friedel-Crafts alkylation to synthesize porous covalent triazine frameworks (CTFs). Herein, we pursue a counterintuitive approach by utilizing a rather destructive method to synthesize well-defined materials with intrinsic porosity. Investigating a model system including carbazole as monomer and cyanuric chloride as triazine node, ball milling is shown to successfully yield porous polymers almost quantitatively. We verified the successful structure formation by an in-depth investigation applying XPS, solid-state NMR and FT-IR spectroscopy. An in situ study of pressure and temperature developments inside the milling chamber in combination with two-dimensional liquid-state NMR spectroscopy reveals insights into the polymerization mechanism. The versatility of this mechanochemical approach is showcased by application of other monomers with different size and geometry. [ABSTRACT FROM AUTHOR]

The predominantly insulating nature of zeolites, as many classes of porous catalysts, can severely impair heat transfer and hence their performance in industrial processes. Strategies developed to engineer the thermophysical properties of technical zeolites for fixed-bed applications comprise the use of conductive secondary phases as structured catalyst supports or as inert diluents. However, the impact of integrating conductive additives into composite zeolite bodies (pellets, extrudates, or granules) has not been widely explored. Here, using a transient hot-plate technique to decouple the distinct contributions of porosity, sample hydration, and temperature, we quantify the impact of metallic (copper), ceramic (silicon carbide, aluminum nitride, boron nitride), and carbonaceous (graphite, carbon nanotubes) phases on the thermal conductivity of shaped zeolites at the body and packed-bed scales. The decisive role of particle morphology, dominating over the intrinsic conductivity of an additive, is corroborated through the three-dimensional reconstruction of data acquired by focused ion beam-scanning electron microscopy and X-ray microtomography coupled with in-situ thermographic studies. In particular, the order-of-magnitude improvement evidenced on application of graphite sheets stems from the extended paths of low thermal resistance created in the millimeter-sized catalyst ensemble. Through the identification of structure-property relations, our approach provides new insights into the rational design of composite porous materials with enhanced heat-transfer properties. [ABSTRACT FROM AUTHOR]

Kitset hollow spheres: The combination of twin polymerization with hard templates makes hollow carbon spheres (HCSs) with tailored properties easily accessible. The thickness and pore texture of the HCS shells and also the diameter of the spherical cavity can be varied. The application potential of synthesized HCS is substantiated by an excellent cycling stability of lithium–sulfur batteries. [ABSTRACT FROM AUTHOR]

This study reports on the extraction of strongly angiotensin-converting enzyme (ACE) inhibiting dipeptides from protein hydrolysates obtained by enzymatic proteolysis. Several dipeptides with different ACE inhibitory activities and hydrophobicities were investigated regarding to their adsorption affinity on commercially available activated carbon material Norit DLC Super 50. This porous carbon exhibits extremely high adsorption capacities for the strongest ACE inhibitor Ile-Trp (IC50=0.7µM) of 726mg/g as well as fast adsorption kinetics due to its micropore structure and small particle size. The filling of the pores was monitored by N2-physisorption revealing that complete pore filling occurred and Ile-Trp adsorption was only limited by the specific pore volume of Norit DLC Super 50, whereas less active peptides were adsorbed less efficient due to their higher hydrophobicity and did not impact Ile-Trp adsorption. After the adsorption, Ile-Trp was recovered by elution with ethanol. Three protein hydrolysates obtained by different enzyme combinations were mixed with activated carbon and the peptide adsorption was investigated by RP-HPLC. The amount of Trp-containing and ACE-inhibiting short chain peptides decreased selectively in contrast to more polar peptides, but the amount of adsorbed Ile-Trp is smaller than for single component adsorption. [ABSTRACT FROM AUTHOR]

Novolac-derived nanoporous carbon beads were used as conductive matrix for lithium-sulfur battery cathodes. We employed a facile self-emulsifying synthesis to obtain sub-micrometer novolac-derived carbon beads with nanopores. After pyrolysis, the carbon beads showed already a specific surface area of 640 m 2 g −1 which was increased to 2080 m 2 g −1 after physical activation. The non-activated and the activated carbon beads represent nanoporous carbon with a medium and a high surface area, respectively. This allows us to assess the influence of the porosity on the electrochemical performance of lithium-sulfur battery cathodes. The carbon/sulfur hybrids were obtained from two different approaches of sulfur infiltration: melt-infusion of sulfur (annealing) and in situ formation of sulfur from sodium thiosulfate. The best performance (∼880 mAh g sulfur −1 at low charge rate; 5th cycle) and high performance stability (>600 mAh g sulfur −1 after 100 cycles) were found for the activated carbon beads when using melt infusion of sulfur. [ABSTRACT FROM AUTHOR]

In this contribution, we report a general surface engineering strategy to transform nonpolar nanocarbons (e.g., carbon nanotube and graphene) into amphiphilic nanocarbons with unique ultrahydrophilic@ultrahydrophobic surface configuration and hierarchical structure by grafting a thin layer of metal-organic frameworks followed by pyrolysis and leaching. The outer ultrahydrophilic carbon layer features rich surface heterogeneity (B-/N-doping both up to ca. 10 at. %) and high density of microporosity, while the inner nonpolar CNT or graphene provides a high electronic conductivity. The unique bipolar surface and high heterogeneity as well as highly accessible hierarchical structures render this family of nanocarbons capable of a high surface efficiency under both aqueous and organic conditions, as it is reflected in the behavior of the electrodes for supercapacitors by comparing a wide range of highly porous nonpolar carbons. The bipolar hierarchical carbons' efficiency in terms of areal capacitance and energy density are 3-6 times and 2-3 times higher than that of typical benchmark materials (e.g., commercially popular YP-50F carbons, CNT, and graphene etc.). More importantly, the study of this series of model carbon materials may help researchers to understand in-depth how carbon surface chemistry with a high density of doping sites influences the wetting, transport, and electrosorption behavior of charged ions in aqueous and organic conditions. [ABSTRACT FROM AUTHOR]

Developing electrocatalysts with low cost, high activity, and good durability is urgently demanded for the wide commercialization of fuel cells. By taking advantage of nanostructure engineering, we fabricated PtAg nanotubular aerogels (NTAGs) with high electrocatalytic activity and good durability via a simple galvanic replacement reaction between the in situ spontaneously gelated Ag hydrogel and the Pt precursor. The PtAg NTAGs have hierarchical porous network features with primary networks and pores from the interconnected nanotubes of the aerogel and secondary networks and pores from the interconnected thin nanowires on the nanotube surface, and they show very high porosities and large specific surface areas. Due to the unique structure, the PtAg NTAGs exhibit greatly enhanced electrocatalytic activity toward formic acid oxidation, reaching 19 times higher metal-based mass current density as compared to the commercial Pt black. Furthermore, the PtAg NTAGs show outstanding structural stability and electrochemical durability during the electrocatalysis. Noble metal-based NTAGs are promising candidates for applications in electrocatalysis not only for fuel cells, but also for other energy-related systems. [ABSTRACT FROM AUTHOR]

We evaluated the potential of several novel porous materials for toluene capture in air under humid conditions. Four novel porous solids of different nature were studied and compared to two reference materials: two hyper-cross-linked polymers HCP and SMP, the metal organic framework MAF-6 and the activated carbon derived from MAF-6 (AC-MAF-6) with references (Norit RB3 and a dealuminated Y zeolite (DAY)). The affinity of the sorbents for toluene was determined from adsorption isotherms recorded at 25 °C and the low pressure part of the isotherms (<100 Pa) were successfully fitted with the Unilan equation allowing extrapolation to sub ppm (<0.1 Pa) concentration range. These equilibrium measurements were complemented by recording the breakthrough curves at 10 Pa of toluene under dry and humid conditions (50% relative humidity). While MAF-6 and DAY show low dynamic capacities under these conditions, HCP and AC-MAF-6 exhibit much better performances which in the case of AC-MAF-6 are close to RB3 activated carbon even under humid conditions. Moreover, these sorbents can be successfully regenerated under mild conditions (200 °C) and show stable performance through adsorption/desorption cycles. Our work suggests that HCP and MAF-6-derived activated carbon are promising materials for toluene capture in air under realistic conditions. [Display omitted] • Potential of novel sorbents for toluene capture under humid conditions is evaluated. • The reactivity was characterized by measuring adsorption isotherms and breakthrough curves. • Activated carbon derived from MAF-6 MOF shows promising properties even below 1 ppm. • Hyper-cross-linked polymers show high capacity at 100 ppm, but not below 1 ppm. • Regenerability of the hyper-cross-linked polymers is confirmed. [ABSTRACT FROM AUTHOR]

Bioactive peptides from food proteins such as natural ACE (angiotensin-converting enzyme)-inhibitors have attracted particular attention for their potential to prevent hypertension. ACE-inhibiting peptides were enriched from food protein hydrolysates prepared from α-lactalbumin and lysozyme by selective adsorption on microporous activated carbons. For the eluate, it was shown by liquid chromatography that the strongest inhibitor isoleucyl-tryptophan was enriched by a factor of 11.2 compared to the initial α-lactalbumin hydrolysate. Natural inhibitors derived from lysozyme hydrolysates (e.g., alanyl-tryptophan) were successfully enriched as well. Identification of the enriched peptide fraction by mass spectroscopy revealed the hydrophobic character of the enriched peptides. The molecular weight distribution of the enriched peptide fraction can be controlled by the pore size distribution of the chosen adsorbent, which was proven by size exclusion chromatography of enriched peptide fractions derived from three different model carbons differing in their pore size. The selective enrichment of natural ACE-inhibitors from the α-lactalbumin hydrolysate lead to a 6 times stronger in vitro ACE-inhibition demonstrating the high potential as ingredients for hypotensive functional foods with reduced side effects. [ABSTRACT FROM AUTHOR]

• MCM-41 and B-PMO possess different wettability to explore methane hydrate formation. • The methane sorption isotherms possess two discrete methane gas consumption steps. • The external and core water in pores is rapidly consumed to form bulk-like hydrate. • The adsorbed water is slowly consumed to form less stable confined hydrates. • A model of water and hydrate distribution in porous media is proposed. The methane hydrate (MH) formation process in confinement was investigated using high-pressure methane sorption experiments on two wet materials with similar pore size distributions, B – PMO (hydrophobic) and MCM – 41 (hydrophilic). Their methane sorption isotherms possess two discrete methane gas consumption steps at ~10 bar and ~ 30 bar at 243 K. A systematic analysis reveals that external water and the so-called 'core water' inside the pore is rapidly consumed in the first step to form bulk-like hydrate, whereas adsorbed water is slowly consumed in the second step to form less stable confined hydrates at higher pressures. Synchrotron powder X-Ray results confirm methane hydrate structure I and reveal that bulk ice is swiftly and fully converted to hydrate in MCM – 41, whereas inactive bulk ice co-exists with MH in B – PMO at 6 MPa demonstrating the huge impact of the surface wettability on the water's behavior during MH formation. [ABSTRACT FROM AUTHOR]