ISSN / EISSN : 1936-0851 / 1936-086X
Published by: American Chemical Society (ACS) (10.1021)
Total articles ≅ 16,552
Latest articles in this journal
ACS Nano; doi:10.1021/acsnano.1c03893
We investigate the anti-Stokes Raman scattering of single carbyne chains confined inside double-walled carbon nanotubes. Individual chains are identified using tip-enhanced Raman scattering (TERS) and heated by resonant excitation with varying laser powers. We study the temperature dependence of carbyne’s Raman spectrum and quantify the laser-induced heating based on the anti-Stokes/Stokes ratio. Due to its molecular size and its large Raman cross section, carbyne holds great promise for local temperature monitoring, with potential applications ranging from nanoelectronics to biology.
ACS Nano; doi:10.1021/acsnano.1c03492
Nanoporous silica membranes exhibit excellent H2/CO2 separation properties for sustainable H2 production and CO2 capture but are prepared via complicated thermal processes above 400 °C, which prevent their scalable production at a low cost. Here, we demonstrate the rapid fabrication (within 2 min) of ultrathin silica-like membranes (∼3 nm) via an oxygen plasma treatment of polydimethylsiloxane-based thin-film composite membranes at 20 °C. The resulting organosilica membranes unexpectedly exhibit H2 permeance of 280–930 GPU (1 GPU = 3.347 × 10–10 mol m–2 s–1 Pa–1) and H2/CO2 selectivity of 93–32 at 200 °C, far surpassing state-of-the-art membranes and Robeson’s upper bound for H2/CO2 separation. When challenged with a 3 d simulated syngas test containing water vapor at 200 °C and a 340 d stability test, the membrane shows durable separation performance and excellent hydrothermal stability. The robust H2/CO2 separation properties coupled with excellent scalability demonstrate the great potential of these organosilica membranes for economic H2 production with minimal carbon emissions.
ACS Nano; doi:10.1021/acsnano.1c03516
Exploring nanostructured transition-metal sulfide anode materials with excellent electrical conductivity is the key point for high-performance alkali metal ion storage devices. Herein, we propose a powerful bottom-up strategy for the construction of a series of sandwich-structured materials by a rapid interfacial self-assembly approach. Oleylamine could act as a functional reagent to guarantee that the nanomaterials self-assemble with MXene. Benefiting from the small size of Co-NiS nanorods, excellent conductivity of MXene, and sandwiched structure of the composite, the Co-NiS/MXene composite could deliver a high discharge capacity of 911 mAh g–1 at 0.1 A g–1 for lithium-ion storage. After 200 cycles at 0.1 A g–1, a high specific capacity of 1120 mAh g–1 could be still remaining, indicating excellent cycling stability. For sodium-ion storage, the composite exhibits high specific capacity of 541 mAh g–1 at 0.1 A g–1 and excellent rate capability (263 mAh g–1 at 5 A g–1). This work offers a straightforward strategy to design and construct MXene-based anode nanomaterials with sandwiched structure for high-performance alkali metal ion storage and even in other fields.
ACS Nano; doi:10.1021/acsnano.1c01879
MoS2 intrinsically show Pt-like hydrogen evolution reaction (HER) performance. Pristine MoS2 displayed low HER activity, which was caused by low quantities of catalytic sites and unsatisfactory conductivity. Then, phase engineering and S vacancy were developed as effective strategies to elevate the intrinsic HER performance. Heterojunctions and dopants were successful strategies to improve HER performance significantly. A couple of state-of-the-art MoS2 catalysts showed HER performance comparable to Pt. Applying multiple strategies in the same electrocatalyst was the key to furnish Pt-like HER performance. In this review, we summarize the available strategies to fabricate superior MoS2 HER catalysts and tag the important works. We analyze the well-defined strategies for fabricating a superior MoS2 electrocatalyst, propose complementary strategies which could help meet practical requirements, and help people design highly efficient MoS2 electrocatalysts. We also provide a brief perspective on assembling practical electrochemical systems by high-performance MoS2 electrocatalysts, apply MoS2 in other important electrocatalysis reactions, and develop high-performance two-dimensional (2D) dichalcogenide HER catalysts not limited to MoS2. This review will help researchers to obtain a better understanding of development of superior MoS2 HER electrocatalysts, providing directions for next-generation catalyst development.
ACS Nano; doi:10.1021/acsnano.1c00687
Safe application of nanoparticles in medicine requires full understanding of their pharmacokinetics including catabolism in the organism. However, information about nanoparticle degradation is still scanty due to difficulty of long-term measurements by invasive techniques. Here, we describe a magnetic spectral approach for in vivo monitoring of magnetic particle (MP) degradation. The method noninvasiveness has allowed performing of a broad comprehensive study of the 1-year fate of 17 types of iron oxide particles. We show a long-lasting influence of five parameters on the MP degradation half-life: dose, hydrodynamic size, ζ-potential, surface coating, and internal architecture. We observed a slowdown in MP biotransformation with an increase of the injected dose and faster degradation of the particles of a small hydrodynamic size. A comparison of six types of 100 nm particles coated by different hydrophilic polymer shells has shown that the slowest (t1/2 = 38 ± 6 days) and the fastest (t1/2 = 15 ± 4 days) degradations were achieved with a polyethylene glycol and polyglucuronic acid coatings, respectively. The most significant influence on the MP degradation was due to the internal architecture of the particles as the coverage of magnetic cores with a solid 39 nm polystyrene layer slowed down the half-life of the core–shell MPs from 48 days to more than 1 year. The revealed deeper insights into the particle degradation in vivo may facilitate rational design of nano- and microparticles with predictable long-term fate in vivo.
ACS Nano; doi:10.1021/acsnano.1c04526
The development of modern electronics has raised great demand for multifunctional materials to protect electronic instruments against electromagnetic interference (EMI) radiation and ice accretion in cold weather. However, it is still a great challenge to prepare high-performance multifunctional films with excellent flexibilty, mechanical strength, and durability. Here, we propose a layer-by-layer assembly of cellulose nanofiber (CNF)/Ti3C2Tx nanocomposites (TM) on a bacterial cellulose (BC) substrate via repeated spray coating. CNFs are hybridized with Ti3C2Tx nanoflakes to improve the mechanical properties of the functional coating layer and its adhesion with the BC substrate. The densely packed hierarchical structure and strong interfacial interactions endows the TM/BC films with good flexibility, ultrahigh mechanical strength (>250 MPa), and desirable toughness (>20 MJ cm–3). Furthermore, benefiting from the densely packed hierarchical structure, the resultant TM/BC films present outstanding EMI shielding effictiveness of 60 dB and efficient electro-/photothermal heating performance. Silicone encapsulation further imparts high hydrophobicity and exceptional durability against solutions and deformations to the multifunctional films. Impressively, the silicone-coated TM/BC film (Si-TM/BC) exhibits desirable low voltage-driven Joule heating and excellent photoresponsive heating performance, which demonstrates great feasibility for efficient thermal deicing under actual conditions. Therefore, we believe that the Si-TM/BC film with excellent mechanical properties and durability holds great promise for the practical applications of EMI shielding and ice accretion elimination.
ACS Nano; doi:10.1021/acsnano.1c05182
The United States Centers for Disease Control and Prevention and World Health Organization recognize that wearing cloth face coverings can slow the transmission of respiratory diseases via source control. Adding a partial layer of material with a high filtration efficiency (FE, e.g., polypropylene sheets that meet the HEPA standard) as an insert can potentially provide additional personal protection; however, data on the necessary areal coverage are sparse. The relationship between insert area ratio (IAR) relative to fabric area, FE, differential pressure (ΔP, a surrogate for breathability), and quality factor (QF, a ratio including FE and ΔP) utilizing two fabrics (rayon and 100% cotton lightweight flannel) and three insert materials (HEPA vacuum bag, sterilization wrap and paper coffee filter) was investigated. The effect of inserts on particle flows mimicking human exhalation is semiquantitatively and qualitatively examined using flow visualization techniques. The following was found: (1) The relationship between FE, ΔP, and QF is complex, and a trade-off exists between personal protection from filtration during inhalation and source control from leakage during exhalation; (2) FE and ΔP of the composite covering increase with IAR, and the rate is dependent upon insert type; (3) improvements (decrements) in the QF of the composite assemblage require inserts with a higher (lower) QF than the fabric and larger differences yield greater gains (losses); (4) the increased ΔP from an insert results in increased leakage during exhalation; (5) to minimize leaks, ΔP must be as low as possible; and (6) small relative areas not covered by an insert (i.e., IAR slightly smaller than 1) strongly deteriorate the benefits of an insert similar to small leaks in a covering.
ACS Nano; doi:10.1021/acsnano.1c02047
It is a significant challenge to design a dense high-sulfur-loaded cathode and meanwhile to acquire fast sulfur redox kinetics and suppress the heavy shuttling in the lean electrolyte, thus to acquire a high volumetric energy density without sacrificing gravimetric performance for realistic Li–S batteries (LSBs). Herein, we develop a cation-doping strategy to tailor the electronic structure and catalytic activity of MoSe2 that in situ hybridized with conductive Ti3C2Tx MXene, thus obtaining a Co-MoSe2/MXene bifunctional catalyst as a high-efficient sulfur host. Combining a smart design of the dense sulfur structure, the as-fabricated highly dense S/Co-MoSe2/MXene monolith cathode (density: 1.88 g cm–3, conductivity: 230 S m–1) achieves a high reversible specific capacity of 1454 mAh g–1 and an ultrahigh volumetric energy density of 3659 Wh L–1 at a routine electrolyte and a high areal capacity of ∼8.0 mAh cm–2 under an extremely lean electrolyte of 3.5 μL mgs–1 at 0.1 C. Experimental and DFT theoretical results uncover that introducing Co element into the MoSe2 plane can form a shorter Co–Se bond, impel the Mo 3d band to approach the Fermi level, and provide strong interactions between polysulfides and Co-MoSe2, thereby enhancing its intrinsic electronic conductivity and catalytic activity for fast redox kinetics and uniform Li2S nucleation in a dense high-sulfur-loaded cathode. This deep work provides a good strategy for constructing high-volumetric-energy-density, high-areal-capacity LSBs with lean electrolytes.
ACS Nano; doi:10.1021/acsnano.1c02632
The long-range alignment of supramolecular structures must be engineered as a first step toward advanced nanopatterning processes aimed at miniaturizing features to dimensions below 5 nm. This study introduces a facile method of directing the orientation of supramolecular columns over wafer-scale areas using faceted surfaces. Supramolecular columns with features on the sub-5 nm scale were highly aligned in a direction orthogonal to that of the facet patterning on unidirectional and nanoscopic faceted surface patterns. This unidirectional alignment of supramolecular columns is also observed by varying the thickness of the supramolecular film or by altering the dimensions of the facet pattern. The ordering behavior of the supramolecular columns can be attributed to the triangular depth profile of the bottom facet pattern. Furthermore, this directed self-assembly principle allows for the continuous alignment of supramolecular structures across ultralarge distances on flexible patterned substrates.
ACS Nano; doi:10.1021/acsnano.1c02944
The ability of amyloid proteins to form stable β-sheet nanofibrils has made them potential candidates for material innovation in nanotechnology. However, such a nanoscale feature has rarely translated into attractive macroscopic properties for mechanically demanding applications. Here, we present a strategy by fusing amyloid peptides with flexible linkers from spidroin; the resulting polymeric amyloid proteins can be biosynthesized using engineered microbes and wet-spun into macroscopic fibers. Using this strategy, fibers from three different amyloid groups were fabricated. Structural analyses unveil the presence of β-nanocrystals that resemble the cross-β structure of amyloid nanofibrils. These polymeric amyloid fibers have displayed strong and molecular-weight-dependent mechanical properties. Fibers made of a protein polymer containing 128 repeats of the FGAILSS sequence displayed an average ultimate tensile strength of 0.98 ± 0.08 GPa and an average toughness of 161 ± 26 MJ/m3, surpassing most recombinant protein fibers and even some natural spider silk fibers. The design strategy and the biosynthetic approach can be expanded to create numerous functional materials, and the macroscopic amyloid fibers will enable a wide range of mechanically demanding applications.