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Despite extensive investigation, the utilization of sulfur and the cycling stability of lithium–sulfur (Li–S) batteries are significantly impeded by the polysulfide shuttle effect and sluggish sulfur reaction kinetics. In this study, aimed at enhancing the performance of Li–S batteries, we focus on the implementation of single metal atom (Be, Mg, Ca, V, Nb, and Ta)-doped TiS2 monolayers as cathode catalysts. Our findings reveal that Be-TiS2, Mg-TiS2, and Ca-TiS2 exhibit superior polysulfide adsorption capabilities and lower values for the rate-determining step in terms of Gibbs free energy. Electronic structure analysis further elucidates that the enhanced anchoring and electrocatalytic activities stem from the upward displacement of the p-band center and the narrowing of the gap within the Δd-p-band, respectively. Moreover, Be-TiS2 and Ca-TiS2 monolayers facilitate the acceleration of the Li2S decomposition reaction and Li-ion migration on their surfaces. This investigation effectively advances our understanding of the role of TiS2 in the polysulfide conversion process and offers valuable insights into the design of cathodes in Li–S batteries. [ABSTRACT FROM AUTHOR]

Superstrength and high-performance textiles hold significant potential in the aviation industry, sporting goods, and extreme environment applications. In contrast, microorganisms that can survive on dry fabric surfaces for several months pose a threat to human health; thus, it is crucial to exploit antibacterial textiles. However, antimicrobial textiles prepared by incorporating functional elements onto the surface of the fabrics are vulnerable to degradation due to the peeling of the functional compounds after prolonged operation. Here, we present a facile approach to in situ grown zeolite imidazole framework 8 (ZIF-8) crystal particles on basalt fibers (BF) by solution impregnation method, in which the ZIF-8 is intensely grafted with the large number of hydroxyl groups on the surface of basalt fibers. The ZIF-8 in situ basalt fiber exhibits excellent antibacterial properties against Pseudomonas aeruginosa , Gram-negative Escherichia coli , and Gram-positive Staphylococcus aureus. Furthermore, the stable and uniform distribution of ZIF-8 on the surface of basalt fibers endows the originally hydrophilic BF with excellent hydrophobicity. Simultaneously, the powerful coordination between ZIF-8 and BF provides ZIF-8 in situ grown basalt fiber with outstanding air/water retainability and remarkable mechanical robustness to satisfy the requirements of routine use and multiple laundering. ZIF-8 in situ grown basalt textiles produced with a highly scalable and low-cost method are promising for large-scale use in extreme environments. [ABSTRACT FROM AUTHOR]

Thickness in sub-10-nm metal film deposition is a seldom explored parameter that can influence not only the film mechanical properties but also the surface functional characteristics. In this study, we designed bilayer systems comprising Au on a poly-(dimethylsiloxane) (PDMS) substrate to reveal a unique thickness-mediated surface morphology evaluation phenomenon. Our results show that, within a specific range of elastic modulus of the selected PDMS substrate, surface wrinkling starts when the deposited theoretical Au thickness is around 0.2 nm, reaches a maximum deformation at thickness 1–2 nm, and disappears when the thickness is equal to or larger than 8 nm. The thickness-mediated wrinkling on and off suggest that film thickness can strongly impact the patterns observed on soft elastomers. This finding indicates that what we observed may not be the intrinsic surface properties but rather thickness-controlled wrinkling. Using 2 nm Au deposition as a highly sensitive nondestructive testing method, a potential application for identifying surface defects on solid surfaces is proposed. [ABSTRACT FROM AUTHOR]

Modulating surface wrinkling is important for a variety of engineering applications. It has been known for more than two decades that the wavelength of surface wrinkles occurring in a metal film–soft polymer system scales linearly with the deposited film thickness. In the current experimental study of ultrathin gold film (0.2–8 nm) deposition on polydimethylsiloxane (PDMS), an unexplored thickness-dependent wrinkling phenomenon is found. By manipulating the deposition sequence as a degree of freedom for tailoring surface topography, we discovered a morphology memory effect where the wrinkle evolution in the subsequent deposition step inherits the surface pattern already formed in the previous step. Moreover, a stepwise deposition targeting 1 nm thick film can lead to 1 order of magnitude higher surface roughness than the one in the continuous deposition. By programming the sequences within 8 nm Au deposition, a surface strain map varying drastically from 0.2% to 27% is realized. Instructed by the strain map, we show the great potentials of tailored wrinkles in alternating surface wettability, enhancing surface Raman scattering, and on-demand tuning of surface adhesion. [ABSTRACT FROM AUTHOR]

The cavitation effect, as a kind of geochemical phenomenon, widely exists under intense hydrodynamic circumstances, turbulent streams, earthquakes, or waterfalls and anywhere else where a shear force abruptly breaks the continuity of liquid surfaces. The development of an efficient and cheap sonocatalyst is hence one of the effective ways to utilize the cavitation effect to harness energy. In this study, we use a flower-like cobalt nitride nanowires catalyst with rich nitrogen-vacancy nanostructures to achieve efficient sonocatalytic hydrogen production in various water resources. In pure water, an exceptional sonocatalytic hydrogen generation rate of 28.5 μmol g–1 h–1 is delivered by the flower-like cobalt nitride nanowires. More interestingly, hydrogen peroxide, a high-value oxidation product, is also detected in the liquid phase after ultrasonic wave vibrations. Due to the acid/alkali resistance and corrosion resistance of the transition metal nitrides (TMNs), cobalt nitride nanowires can also produce hydrogen in acidic water, alkaline water, seawater, and wastewater. Enriched active sites in cobalt nitride nanowires greatly promote the recombination of radicals generated by the implosion of cavitation bubbles, which promotes sonochemical reaction efficiency. In addition, the cobalt nitride nanowire catalyst displays excellent stability and reusability during the sonochemical catalytic reaction. The findings are anticipated to be useful for further research on transition metal nitride materials as prospective sonocatalysts for energy conversion and environmental remediation. [ABSTRACT FROM AUTHOR]

The fabrication of thin composite films incorporating metal-based fillers with a delicate structure to achieve high electromagnetic interference shielding effectiveness (EMI SE) at low metal content remains a great challenge. In this work, benefiting from the excellent electrical conductivity of Ag nanoparticles, Ag nanoparticle-coated polystyrene (PS@Ag) microspheres with a large PS core were selected as electrically conductive fillers, and the volume exclusion effect guaranteed the construction of an electrically conductive network with low silver loading. A spontaneous process to construct a segregated laminar structure with a three-dimensional electrically conductive network happened with the assistance of a gravity-driven effect. The flexible thin films with a low amount of silver exhibited outstanding EMI SE per unit thickness (SE/d). To further investigate the effect of the structure on the EMI SE efficiency, it is found that the alternate interfaces play a critical role in enhancing shielding performance by stacking multiple films compared to the bulk films obtained by casting. The EMI SE for an only 0.3 mm triple-piece stacking film with 6.3 wt % Ag loading could reach 55.3 dB compared to 37.2 dB for the triple-thickness casting film. Using the stacking process results in easy accessibility for tailored composites with the desired EMI SE, which supplies a new strategy for the design of shielding materials in the next-generation electronics. [ABSTRACT FROM AUTHOR]

Direct asymmetric α-C-H conjugate addition of propargylamines to α,β-unsaturated ketones remains a great challenge due to the low α-amino C-H acidity of propargylamines and the nucleophilic interference of the NH 2 group. Utilizing a new type of pyridoxals featuring a benzene-pyridine biaryl skeleton and a bulky amide side chain as carbonyl catalyst, we have accomplished direct asymmetric α-C-H conjugate addition of NH 2 -unprotected propargylamines to α,β-unsaturated ketones. The adducts undergo subsequent in situ intramolecular cyclization, delivering a wide range of chiral polysubstituted 1-pyrrolines in high yields (up to 92%) with excellent diastereo- and enatioelectivities (up to >20:1 dr and 99% ee). This work has demonstrated a straightforward approach to access pharmaceutically important chiral 1-pyrrolines, and it has also provided an impressive instance of direct asymmetric functionalization of inert C-H bonds enabled by biomimetic organocatalysts.

Carbon nanotubes/polyaniline (CNTs/PANI) composites have attracted significant attention in thermoelectric (TE) conversion due to their excellent stability and easy synthesis. However, their TE performance is far from practical demands, and few flexible yarns/fibers have been developed for wearable electronics. Herein, we developed flexible CNTs/PANI yarns with outstanding TE properties via facile soaking of CNT yarns in a PANI solution, in which the PANI layer was coated on the CNT surface and served as a bridge to interconnect adjacent CNT filaments. With optimizing PANI concentration, immersing duration, and doping level of PANI, the power factor reached 1294 μW m -1 K -2 with a high electrical conductivity of 3651 S cm -1 , which is superior to that of most of the reported CNTs/PANI composites and organic yarns. Combining outstanding TE performance with excellent bending stability, a highly integrated and flexible TE generator was assembled consisting of 40 pairs of interval p-n segments, which generate a high power of 377 nW at a temperature gradient of 10 K along the out-of-plane direction. These results indicate the promising application of CNTs/PANI yarns in wearable energy harvesting.