Developing noble‐metal‐free electrocatalysts is important to industrially viable ammonia synthesis through the nitrogen reduction reaction (NRR). However, the present transition‐metal ...electrocatalysts still suffer from low activity and Faradaic efficiency due to poor interfacial reaction kinetics. Herein, an interface‐engineered heterojunction, composed of CoS nanosheets anchored on a TiO2 nanofibrous membrane, is developed. The TiO2 nanofibrous membrane can uniformly confine the CoS nanosheets against agglomeration, and contribute substantially to the NRR performance. The intimate coupling between CoS and TiO2 enables easy charge transfer, resulting in fast reaction kinetics at the heterointerface. The conductivity and structural integrity of the heterojunction are further enhanced by carbon nanoplating. The resulting C@CoS@TiO2 electrocatalyst achieves a high ammonia yield (8.09×10−10 mol s−1 cm−2) and Faradaic efficiency (28.6 %), as well as long‐term durability.
Junction box: An interface‐engineered heterojunction, composed of carbon‐nanoplated CoS@TiO2 nanofibrous membrane, is developed for the nitrogen reduction reaction. The resulting C@CoS@electrocatalyst achieves strikingly high ammonia yield (8.09×10−10 mol s−1 cm−2) and Faradaic efficiency (28.6 %), as well as long‐term durability.
Nanopipettes provide a promising confined space that enables advances in electrochemical, optical, and mass spectrometric measurements at the nanoscale. They have been employed to reveal the hidden ...population properties and dynamics of single molecules and single particles. Moreover, new detection mechanisms based on nanopipettes have led to detailed information on single cells at high spatial and temporal resolution. In this Minireview, we focus on the fabrication and characterization of nanopipettes, summarize their wide applications for the analysis of single entities, and conclude with an outlook for advanced practical sensing.
The preparation and characterization of nanopipettes—promising devices for electrochemical, optical, and mass spectrometric measurements at the nanoscale—are the themes of this Minireview. Their application enables the dynamics and properties of single molecules and particles to be uncovered. Furthermore, new detection mechanisms based on nanopipettes have led to detailed information on single cells at high resolution.
A conceptually new, metal‐free electrocatalyst, black phosphorus (BP) is presented, which is further downsized to quantum dots (QDs) for larger surface areas, and thus, more active sites than the ...bulk form. However, BP QDs are prone to agglomeration, which inevitably results in the loss of active sites. Besides, their poor conductivity is not favorable for charge transport during electrolysis. To solve these problems, an electrochemically active, electrically conductive matrix, black tin oxide (SnO2−x) nanotubes, is employed for the first time. Through facile self‐assembly, BP QDs are stably confined on the SnO2−x nanotubes due to Sn‐P coordination, resulting in a robust, double‐active electrocatalyst. Benefiting from their synergistic superiority, the BP@SnO2−x nanotubes deliver impressively high ammonia yield and Faradaic efficiency, which represent a successful attempt toward advanced hybrid electrocatalysts for ambient nitrogen fixation.
Through facile self‐assembly, black phosphorus quantum dots are stably confined on SnO2−x nanotubes, which serve as an electrocatalytically active and electrically conductive matrix. Benefiting from their synergistic superiority, the two components result in a robust, double‐active electrocatalyst delivering impressively high ammonia yield and Faradaic efficiency.
Proteins are responsible for the occurrence and treatment of many diseases, and therefore protein sequencing will revolutionize proteomics and clinical diagnostics. Biological nanopore approach has ...proved successful for single‐molecule DNA sequencing, which resolves the identities of 4 natural deoxyribonucleotides based on the current blockages and duration times of their translocations across the nanopore confinement. However, open challenges still remain for biological nanopores to sequentially identify each amino acid (AA) of single proteins due to the inherent complexity of 20 proteinogenic AAs in charges, volumes, hydrophobicity and structures. Herein, we focus on recent exciting advances in biological nanopores for single‐molecule protein sequencing (SMPS) from native protein unfolding, control of peptide translocation, AA identification to applications in disease detection.
Nanopore electrochemistry offers a bright prospect for single‐molecule protein sequencing by measuring specific interactions between amino acids based on their natural structure and chemistry continuity and diversity. This Minireview focusses on recent advances in biological nanopores from protein unfolding, peptide translocation, amino acid identification to diagnostic application.
Recently, a new class of 2D materials, i.e., transition metal carbides, nitrides, and carbonitrides known as MXenes, is unveiled with more than 20 types reported one after another. Since they are ...flexible and conductive, MXenes are expected to compete with graphene and other 2D materials in many applications. Here, a general route is reported to simple self‐assembly of transition metal oxide (TMO) nanostructures, including TiO2 nanorods and SnO2 nanowires, on MXene (Ti3C2) nanosheets through van der Waals interactions. The MXene nanosheets, acting as the underlying substrate, not only enable reversible electron and ion transport at the interface but also prevent the TMO nanostructures from aggregation during lithiation/delithiation. The TMO nanostructures, in turn, serve as the spacer to prevent the MXene nanosheets from restacking, thus preserving the active areas from being lost. More importantly, they can contribute extraordinary electrochemical properties, offering short lithium diffusion pathways and additional active sites. The resulting TiO2/MXene and SnO2/MXene heterostructures exhibit superior high‐rate performance, making them promising high‐power and high‐energy anode materials for lithium‐ion batteries.
Transition metal oxide (TMO) nanostructures are self‐assembled on MXene nanosheets in tetrahydrofuran through van der Waals interactions, resulting in novel TMO/MXene heterostructures. Due to remarkable morphological and functional synergy, the TMO/MXene heterostructures exhibit superior high‐rate performance, which rank them as promising anode materials for fast and stable lithium storage.
Pseudouridylation is the most abundant internal post-transcriptional modification of stable RNAs, with fundamental roles in the biogenesis and function of spliceosomal small nuclear RNAs (snRNAs) and ...ribosomal RNAs (rRNAs). Recently, the first transcriptome-wide maps of RNA pseudouridylation were published, greatly expanding the catalogue of known pseudouridylated RNAs. These data have further implicated RNA pseudouridylation in the cellular stress response and, moreover, have established that mRNAs are also targets of pseudouridine synthases, potentially representing a novel mechanism for expanding the complexity of the cellular proteome.
Surface-supported isolated atoms in single-atom catalysts (SACs) are usually stabilized by diverse defects. The fabrication of high-metal-loading and thermally stable SACs remains a formidable ...challenge due to the difficulty of creating high densities of underpinning stable defects. Here we report that isolated Pt atoms can be stabilized through a strong covalent metal-support interaction (CMSI) that is not associated with support defects, yielding a high-loading and thermally stable SAC by trapping either the already deposited Pt atoms or the PtO
units vaporized from nanoparticles during high-temperature calcination. Experimental and computational modeling studies reveal that iron oxide reducibility is crucial to anchor isolated Pt atoms. The resulting high concentrations of single atoms enable specific activities far exceeding those of conventional nanoparticle catalysts. This non defect-stabilization strategy can be extended to non-reducible supports by simply doping with iron oxide, thus paving a new way for constructing high-loading SACs for diverse industrially important catalytic reactions.
Ceramic aerogels are attractive for many applications due to their ultralow density, high porosity, and multifunctionality but are limited by the typical trade-off relationship between mechanical ...properties and thermal stability when used in extreme environments. In this work, we design and synthesize ceramic nanofibrous aerogels with three-dimensional (3D) interwoven crimped-nanofibre structures that endow the aerogels with superior mechanical performances and high thermal stability. These ceramic aerogels are synthesized by a direct and facile route, 3D reaction electrospinning. They display robust structural stability with structure-derived mechanical ultra-stretchability up to 100% tensile strain and superior restoring capacity up to 40% tensile strain, 95% bending strain and 60% compressive strain, high thermal stability from -196 to 1400 °C, repeatable stretchability at working temperatures up to 1300 °C, and a low thermal conductivity of 0.0228 W m
K
in air. This work would enable the innovative design of high-performance ceramic aerogels for various applications.
The key to bringing the electrocatalytic nitrogen fixation from conception to application lies in the development of high‐efficiency, cost‐effective electrocatalysts. Layered double hydroxides ...(LDHs), also known as hydrotalcites, are promising electrocatalysts for water splitting due to multiple metal centers and large surface areas. However, their activities in the electrocatalytic nitrogen fixation are unsatisfactory. Now, a simple and effective way of phosphorus doping is presented to regulate the charge distribution in LDHs, thus promoting the nitrogen adsorption and activation. The P‐doped LDHs are further coupled to a self‐supported, conductive matrix, that is, a carbon nanofibrous membrane, which prevents their aggregation as well as ensuring rapid charge transfer at the interface. By this strategy, decent ammonia yield (1.72×10−10 mol s−1 cm−2) and Faradaic efficiency (23 %) are delivered at −0.5 V vs. RHE in 0.1 m Na2SO4.
Through phosphorus doping, the charge distribution in Fe‐Ni layered double hydroxide (LDH) is regulated to promote the activation of nitrogen. This strategy offers an opportunity of tapping the unknown potentials of the well‐known hydrotalcites (LDHs) in the field of electrocatalytic nitrogen fixation.
Gold nanoparticles (AuNPs) have been demonstrated to serve as effective nanomaterial‐based enzyme mimetics (nanozymes) for a number of enzymatic reactions under mild conditions. The intrinsic glucose ...oxidase and peroxidase activities of single AuNPs and Ag–Au nanohybrids, respectively, were investigated by single NP collision electrochemical measurements. A significantly high turnover number of nanozymes was obtained from individual catalytic events compared with the results from the classical, ensemble‐averaged measurements. The unusual enhancement of catalytic activity of single nanozymes is believed to originate from the high accessible surface area of monodispersed NPs and the high activities of carbon‐supported NPs during single‐particle collision at a carbon ultramicroelectrode. This work introduces a new method for the precise characterization of the intrinsic catalytic activities of nanozymes, giving further insights to the design of high‐efficiency nanomaterial catalysts.
Imitation is the sincerest form of flattery: The intrinsic glucose‐oxidase‐ and peroxidase‐mimicking activities of single AuNPs and Ag–Au nanohybrids, respectively, were quantified using stochastic collision electrochemistry, providing new insights for the design of high‐efficiency, nanomaterial‐based catalysts.
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