Insulator-Transition-Induced Degradation of Pyrochlore Ruthenates in Electrocatalytic Oxygen Evolution and Stabilization through Doping.

Ru-based pyrochlores (e.g., YRuO) are promised to replace IrO in polymer electrolyte membrane (PEM) electrolyzers.

Artificial intelligence for the prevention and prediction of colorectal neoplasms.

Background: Colonoscopy is a useful as a cancer screening test. However, in countries with limited medical resources, there are restrictions on the widespread use of endoscopy. Non-invasive screening methods to determine whether a patient requires a colonoscopy are thus desired.

Development and Optimization of Water-Soluble Double-Walled Carbon Nanotubes by Effective Surface Treatment of Inner Walls.

Carbon nanotubes are a significant class of nanomaterials with distinctive properties that have led to their application in a variety of fields, such as polymer composites, medicine, electronics, and material science. However, their nonpolar nature and insolubility in polar solvents limit their applications. To address this issue, highly functionalized and water-soluble double-walled carbon nanotubes (DWNTs) were developed by selectively oxidizing the inner walls of the DWNTs using oleum and nitric acid.

A finger-jointing model for describing ultrastructures of cellulose microfibrils.

In this paper, we propose a finger-jointing model to describe the possible ultrastructures of cellulose microfibrils based on new observations obtained through heating of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized cellulose nanofibrils (CNFs) in saturated water vapor. We heated the micrometers-long TEMPO-CNFs in saturated water vapor (≥ 120 °C, ≥ 0.2 MPa) and observed a surprising fact that the long TEMPO-CNFs unzipped into short (100 s of nanometers long) fibers.

Thermodynamics of Linear Carbon Chains.

Linear carbon chains (LCCs) are one-dimensional materials with unique properties, including high Debye temperatures and restricted selection rules for phonon interactions. Consequently, their Raman C-band frequency's temperature dependence is a probe to their thermal properties, which are well described within the Debye formalism even at room temperatures. Therefore, with the basis on a semiempirical approach we show how to use the C band to evaluate the LCCs' internal energy, heat capacity, coefficient of thermal expansion, thermal strain, and Grüneisen parameter, providing universal relations for these quantities in terms of the number of carbons atoms and the temperature.

Aerogels from copper (II)-cellulose nanofibers and carbon nanotubes as absorbents for the elimination of toxic gases from air.

A novel deodorizer that is capable of selectively eliminating the odorous chemicals, such as ammonia, trimethylamine, hydrogen sulfide and methyl mercaptan, is described. The deodorizer is a nanostructured aerogel by nature, consisting of 2,2-6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized cellulose nanofibrils (CNF), transition metal divalent cations (M), and multi-walled carbon nanotubes (CNT) as the constitutive elements. CNF are firstly mixed with M (M, in this paper, typifies Ni, Co and Cu) to form CNF-M complexes, monodispersed CNT is then mixed to prepare CNT/CNF-M waterborne slurries; CNT/CNF-M hybridized aerogels are finally obtained via freezing-drying of the CNT/CNF-M waterborne slurries.

Single-atom doping of MoS with manganese enables ultrasensitive detection of dopamine: Experimental and computational approach.

Two-dimensional transition metal dichalcogenides (TMDs) emerged as a promising platform to construct sensitive biosensors. We report an ultrasensitive electrochemical dopamine sensor based on manganese-doped MoS synthesized via a scalable two-step approach (with Mn ~2.15 atomic %).

Nanocomposite desalination membranes made of aromatic polyamide with cellulose nanofibers: synthesis, performance, and water diffusion study.

Reverse osmosis membranes of aromatic polyamide (PA) reinforced with a crystalline cellulose nanofiber (CNF) were synthesized and their desalination performance was studied. Comparison with plain PA membranes shows that the addition of CNF reduced the matrix mobility resulting in a molecularly stiffer membrane because of the attractive forces between the surface of the CNFs and the PA matrix. Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy results showed complex formation between the carboxy groups of the CNF surface and the m- phenylenediamine monomer in the CNF-PA composite.

Enhanced desalination performance in compacted carbon-based reverse osmosis membranes.

Reverse osmosis membranes typically suffer compaction during the initial stabilization stage due to the applied hydraulic pressure, altering the desalination performance. The elucidation of the underlying transformations during compaction is key for further development of new membranes and its deployment in real-world scenarios. Hydraulic compaction of amorphous carbon (a-C) based membranes under cross-flow operation for water purification and desalination has been observed experimentally, and analysed employing molecular dynamics simulations.

Enhanced Antifouling Feed Spacer Made from a Carbon Nanotube-Polypropylene Nanocomposite.

Spacers are widely used in membrane technologies to reduce fouling and concentration polarization. Fouling can start from the spacer surface and grow, thereby reducing flux, selectivity, and operation lifetime. Fluorescein isothiocyanate labeled bovine serum albumin was used for fouling studies and observed during cross-flow filtration operation for up to 144 h.

Graphite Whiskers Derived from Waste Coffee Grounds Treated at High Temperature.

Graphite whiskers (GWs) are obtained from coffee grounds (CGs) treated at 2500 °C for 1 h in the presence of Ar gas at 1 atm. The majority of the GWs formed inside the CGs shell are rod-like with a conical tip with diameter and length in the range between 1 to 3 µm and 4 to 10 µm, respectively. At first, the carbon layer might be grown in a turbostratic manner, and then progressively graphitized at higher temperature.

Nitrogen self-doped activated carbons the direct activation of leaves for high energy density supercapacitors.

In this study, nitrogen self-doped activated carbons (ACs) obtained the direct activation of green leaves (SSLs) for high energy density supercapacitors were investigated. The SSL-derived direct-activated carbons (hereinafter referred to SD-ACs) were synthesized by impregnating sodium hydroxide as an activating agent and heating up to 720 °C without a hydrothermal carbonization or pyrolysis step. The optimum condition was investigated by varying the weight ratio of raw SSLs to NaOH.

New Insights in the Natural Organic Matter Fouling Mechanism of Polyamide and Nanocomposite Multiwalled Carbon Nanotubes-Polyamide Membranes.

Polyamide (PA) membranes comprise most of the reverse osmosis membranes currently used for desalination and water purification. However, their fouling mechanisms with natural organic matter (NOM) is still not completely understood. In this work, we studied three different types of PA membranes: a laboratory made PA, a commercial PA, and a multiwalled carbon nanotube (CNT-PA nanocomposite membrane during cross-flow measurements by NaCl solutions including NOM, humic acid (HA), or alginate, respectively).

Preparation and electrochemical performance of nitrogen-enriched activated carbon derived from silkworm pupae waste.

In this study, nitrogen-enriched activated carbon from silkworm pupae waste (P-AC) was successfully prepared and its electrochemical performances in aqueous and organic electrolytes were investigated. Silkworm pupae waste is beneficial because it is a nitrogen-enriched, inexpensive, and locally available material. The preparation process includes hydrothermal treatment of the silkworm pupae waste at 200 °C, and chemical activation using zinc chloride at activation temperatures of 700, 800 and 900 °C (P700, P800, and P900, respectively).

Defect Engineering and Surface Functionalization of Nanocarbons for Metal-Free Catalysis.

With the advent of carbon nanotechnology, which initiated significant research efforts more than two decades ago, novel materials for energy harvesting and storage have emerged at an amazing pace. Nevertheless, some fundamental applications are still dominated by traditional materials, and it is especially evident in the case of catalysis, and environmental-related electrochemical reactions, where precious metals such as Pt and Ir are widely used. Several strategies are being explored for achieving competitive and feasible metal-free carbon nanomaterials, among which doping and defect engineering approaches within nanocarbons are recurrent and promising.

Effect of boron doping on the electrical conductivity of metallicity-separated single walled carbon nanotubes.

We explored the effect of substitutional boron doping on the electrical conductivity of a metallicity-separated single walled carbon nanotube (SWCNT) assembly. Boron atoms were introduced into semiconducting (S)- and metallic (M)-SWCNT assemblies using high temperature thermal diffusion and the concentration of the doped boron atoms was controlled by the thermal treatment temperature. Depending on the conduction mechanism of the SWCNT assembly, both positive and negative effects upon boron incorporation are observed.

Effective Antiscaling Performance of Reverse-Osmosis Membranes Made of Carbon Nanotubes and Polyamide Nanocomposites.

The antiscaling properties of multiwalled carbon nanotube (MWCNT)-polyamide (PA) nanocomposite reverse-osmosis (RO) desalination membranes (MWCNT-PA membranes) were studied. An aqueous solution of calcium chloride (CaCl) and sodium bicarbonate (NaHCO) was used to precipitate in situ calcium carbonate (CaCO) to emulate scaling. The MWCNT contents of the studied nanocomposite membranes prepared by interfacial polymerization ranged from 0 wt % (plain PA) to 25 wt %.

Effective NaCl and dye rejection of hybrid graphene oxide/graphene layered membranes.

Carbon nanomaterials are robust and possess fascinating properties useful for separation technology applications, but their scalability and high salt rejection when in a strong cross flow for long periods of time remain challenging. Here, we present a graphene-based membrane that is prepared using a simple and environmentally friendly method by spray coating an aqueous dispersion of graphene oxide/few-layered graphene/deoxycholate. The membranes were robust enough to withstand strong cross-flow shear for a prolonged period (120 h) while maintaining NaCl rejection near 85% and 96% for an anionic dye.

Antiorganic Fouling and Low-Protein Adhesion on Reverse-Osmosis Membranes Made of Carbon Nanotubes and Polyamide Nanocomposite.

We demonstrate efficient antifouling and low protein adhesion of multiwalled carbon nanotubes-polyamide nanocomposite (MWCNT-PA) reverse-osmosis (RO) membranes by combining experimental and theoretical studies using molecular dynamics (MD) simulations. Fluorescein isothiocyanate (FITC)-labeled bovine serum albumin (FITC-BSA) was used for the fouling studies. The fouling was observed in real time by using a crossflow system coupled to a fluorescence microscope.

Corrigendum: Nitrogen-doped porous carbon monoliths from polyacrylonitrile (PAN) and carbon nanotubes as electrodes for supercapacitors.

This corrects the article DOI: 10.1038/srep40259.

Low-temperature Synthesis of Heterostructures of Transition Metal Dichalcogenide Alloys (WMoS) and Graphene with Superior Catalytic Performance for Hydrogen Evolution.

Large-area (∼cm) films of vertical heterostructures formed by alternating graphene and transition-metal dichalcogenide (TMD) alloys are obtained by wet chemical routes followed by a thermal treatment at low temperature. In particular, we synthesized stacked graphene and WMoS alloy phases that were used as hydrogen evolution catalysts. We observed a Tafel slope of 38.

Cellulose nanofiber backboned Prussian blue nanoparticles as powerful adsorbents for the selective elimination of radioactive cesium.

On 11 March 2011, the day of the unforgettable disaster of the 9 magnitude Tohoku earthquake and quickly followed by the devastating Tsunami, a damageable amount of radionuclides had dispersed from the Fukushima Daiichi's damaged nuclear reactors. Decontamination of the dispersed radionuclides from seawater and soil, due to the huge amounts of coexisting ions with competitive functionalities, has been the topmost difficulty. Ferric hexacyanoferrate, also known as Prussian blue (PB), has been the most powerful material for selectively trapping the radioactive cesium ions; its high tendency to form stable colloids in water, however, has made PB to be impossible for the open-field radioactive cesium decontamination applications.

Ultrasensitive molecular sensor using N-doped graphene through enhanced Raman scattering.

As a novel and efficient surface analysis technique, graphene-enhanced Raman scattering (GERS) has attracted increasing research attention in recent years. In particular, chemically doped graphene exhibits improved GERS effects when compared with pristine graphene for certain dyes, and it can be used to efficiently detect trace amounts of molecules. However, the GERS mechanism remains an open question.