It is of great significance to develop highly efficient and superior stable oxygen evolution reaction (OER) electrocatalysts for upcoming electrochemical conversion technologies and clean energy ...systems. Here, an assembled 3D electrode is synthesized by a one‐step solvothermal process using such an original OER electrocatalyst. During the solvothermal process, Ni ions released from Ni foam in acidic solution and Fe ions added exogenously act as metal centers and coordinate with terephthalic acid (TPA) organic molecules by robust coordinate bonds, and finally, NiFe‐based metal–organic framework (MOF) nanosheets in situ grown on Ni foam, i.e., MIL‐53(FeNi)/NF, are prepared. This binder‐free 3D electrode shows superior OER activity with high current density (50 mA cm−2) at an overpotential of 233 mV, a Tafel slope of 31.3 mV dec−1, and excellent stability in alkaline aqueous solution (1 m KOH). It is discovered that introduction of Fe into MIL‐53 structure increases electrochemically‐active areas as well as reaction sites, accelerated electron transport capability, and modulated electronic structure to enhance catalytic performance. Besides, first principles calculations show that MIL‐53(FeNi) is more favorable for foreign atoms' adsorption and has increased 3d orbital electron density boosting intrinsic activity. This work elucidates a promising electrode for electrocatalysts and enriches direct application of MOF materials.
Metal–organic framework nanosheets are successfully grown on a conductive Ni foam surface, as a binder‐free 3D electrode and applied to catalyzing the oxygen evolution reaction. This electrode delivers excellent catalytic activity and superior stability with a current density of 50 mA cm−2 at an overpotential as low as 233 mV. The reaction mechanism is explored with the assistance of density functional theory calculations.
Water and ion transport in nanochannels is an intriguing topic that has been extensively investigated in several energy- and environment-related research fields. Recently developed two-dimensional ...(2D) materials are ideal building blocks for constructing confined nanochannels by self-stacking. Among these, graphene oxide (GO) is the most frequently employed as the starting material because of its excellent solution processability. Since solvation of the GO nanostructure usually impairs the function of nanochannels, in this study, chemically converted graphene was prepared using a one-step method, to simultaneously acquire the desired stability and functionality of the nanochannels. The confined channels with high charge densities are capable of excluding ∼90% NaCl solutes from water in a pressure-driven filtration process. This surpasses the performance of most GO desalination membranes reported in the literature. Thus, this study provides useful information for the feasible development of ion-exclusion nanochannel membranes based on the proposed nanochannel-confined charge repulsion mechanism.
Abstract
Nitric oxide (NO) has been implicated in a variety of physiological and pathological processes. Monitoring cellular levels of NO requires a sensor to feature adequate sensitivity, transient ...recording ability and biocompatibility. Herein we report a single-atom catalysts (SACs)-based electrochemical sensor for the detection of NO in live cellular environment. The system employs nickel single atoms anchored on N-doped hollow carbon spheres (Ni SACs/N-C) that act as an excellent catalyst for electrochemical oxidation of NO. Notably, Ni SACs/N-C shows superior electrocatalytic performance to the commonly used Ni based nanomaterials, attributing from the greatly reduced Gibbs free energy that are required for Ni SACs/N-C in activating NO oxidation. Moreover, Ni SACs-based flexible and stretchable sensor shows high biocompatibility and low nanomolar sensitivity, enabling the real-time monitoring of NO release from cells upon drug and stretch stimulation. Our results demonstrate a promising means of using SACs for electrochemical sensing applications.
Comprehensive fouling resistance, high permeability, high rejection, and robustness are indispensable criteria for advanced oil/water separation membranes intended for sustainable operation under ...harsh conditions. Accordingly, in the present study, a new class of zwitterionic-polyelectrolyte-grafted aliphatic polyketone (PK) membranes was prepared by the highly controllable surface-initiated atom transfer radical polymerization (SI-ATRP) of N-(3-sulfopropyl)-N-methacroyl-oxyethyl-N,N-dimethylammonium betaine (SBMA) on highly porous and hydroxylated PK membranes. The PK-g-PSBMA membrane prepared with 10-min grafting modification exhibited excellent solvent-resistant underoil superhydrophilicity as well as underwater superoleophobicity and ultralow protein adhesion. The low mass-transfer resistance, low fouling potential, and strong solvent resistance of the porous hydroxylated PK substrate along with the ultralow fouling nature of the zwitterionic SMBA layer, endowed the PK-g-PSBMA membranes with self-cleaning properties, sustainably high emulsion fluxes of 1200–1800 L m−2 h−1 bar−1, low oil permeations at 6–33 ppm, and high flux recovery ratios of 82–98%, even for difficult micro- and nanoemulsions containing small oil droplets and complicated pollutants (surfactant, high salinity, and natural organic matters). Thus, PK-g-PSBMA membranes with simple preparation route and comprehensive performances show great potential for treatment of challenging oily wastewater.
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•Zwitterionic surface layer readily grafted onto hydroxylated PK membrane via ATRP.•Ultralow adhesive underwater superoleophobicity and robust self-cleaning achieved.•Comprehensive antifouling, solvent-resistance and small cutoff pore size combined.•High emulsion flux and oil rejection sustained for difficult oil-in-water emulsions.
Exploration of high-efficiency and inexpensive electrocatalysts for the oxygen evolution reaction (OER) is of great importance for the design of renewable energy storage and conversion devices. ...Herein, we prepared amorphous MoSx-encapsulated Co(OH)2 nanosheets (aMoSx/Co(OH)2 NSs) as strongly robust and active OER electrocatalysts via a three-step procedure: first, Co(OH)2 nanosheets with catalytically active octahedral MO6 structures were synthesized by the hydrothermal process; second, violent ultrasonication was applied to exfoliate individual nanosheets from stacked Co(OH)2 sheets and break them down into smaller sheets and attach MoS42− ions uniformly on the nanosheets; third, MoS42− ions were thermally decomposed into amorphous MoSx on the Co(OH)2 nanosheets. The role of the incorporation of the amorphous MoSx nanostructure was to enhance the surface hydrophilicity for the availability of H2O and accelerate the electron transport capability for kinetic activities. Furthermore, the interaction between MoSx and Co(OH)2 is proposed to induce electron transfer from amorphous MoSx to Co(OH)2, which will promote the basic environment for cobalt sites, break the Co–O bond, favor the release of O2 molecules, and thus enhance the OER process. Optimization of the Co/Mo molar ratio demonstrated that aMoSx/Co(OH)2 NSs with the Co/Mo molar ratio of 8 had the best OER activity and delivered the overpotential of 350 mV at the current density of 10 mA cm−2 and the Tafel slope of 65.4 mV dec−1 in 0.1 M KOH. This study enriches the research on non-first-row (3d) metal incorporation for high-efficient OER catalysts and offers an alternative to noble metal catalysts.
Environmental issues caused by oily pollutants is one of the most severe challenges for the global ecosystem and public health. To develop the advanced membrane materials with superior antifouling ...property is urgently needed for highly efficient oily wastewater purification. In this study, an ultrathin polydopamine layer with a controllable thickness of ~90 nm was decorated onto a porous polyketone substrate via an extremely simple and scalable surface modification process. The ammonia initiator facilitated the ultrafine polydopamine nanoparticles (with its size about 30 nm) in-situ assembling. Benefiting from the ultrathin surface modification, the resultant polydopamine decorated polyketone (PDA-d-PK) membrane performed ultrahigh water permeance up to 11600 L m−2 h−1 bar−1. This membrane also exhibited a superior oily emulsions separation property with remarkably high permeance up to 8300–10600 L m−2 h−1 bar−1, and high rejection ratio more than 99.9% against various oily phases, including hexane, hexadecane, petroleum ether, and soybean oil. The hierarchical nanosphere-like polydopamine layer with superhydrophilicity/underwater superoleophobicity also endowed the PDA-d-PK membrane with an excellent antifouling performance against the oily emulsions containing surfactant, protein, and natural organic material. The PDA-d-PK membrane also featured a superior tolerance and durability under challenging conditions of salty, strong acid/alkali solutions, and a variety of organic solvents. This work provides an insight into the facile preparation of an ultrathin polydopamine membrane with simultaneous enhancement in separation and antifouling properties for highly-efficient oil-water emulsions separation.
•Micro/nanosphere-like polydopamine particles were assembled on a polyketone substrate.•The polydopamine layer could be finely tuned by the deposition time and ammonia content.•Underwater superoleophobicity and robust self-cleaning properties were obtained.•High water/emulsion flux, oil rejection, and antifouling property were achieved.
In this work, Ag-based compound nanorods were molecularly synthesized followed by the incorporation into PA active layer through interfacial polymerization (IP) process. This strategy achieved the ...concurrent construction of molecular sieving architecture and tunable surface function, by precisely controlling the release of zero-dimensional Ag nanoparticles (AgNPs, ∼5 nm), via in situ decomposition of the pH-responsive compounds serving as sacrificial nanocapsules. Featuring favorable interactions and sizes, the released ultrafine AgNPs serves as a quasi-molecule-scale regulator to generate the thin-film nanocomposite (TFN) membrane with wrinkled surface microstructures and loose internal architecture, due to the adjusted diffusion rate of amine monomers toward the organic phase during IP, while endowing the resultant membrane with superior antifouling/anti-biofouling properties. The newly-developed AgNPs embedded PA (AgNPs@PA) TFN membrane exhibited a high water permeance of 10.4 L m−2 h−1 bar−1 (more than twice that of the pristine PA 4.5 L m−2 h−1 bar−1) with a rejection ratio of 97.7% for Na2SO4, performing a competitive desalination property among the state-of-the-art nanofiltration membranes. The proposed technique for tuning the membrane microstructure opens opportunities for developing high-performance nanofiltration membranes for energy-efficient water remediation and treatment applications.
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•The Ag NPs incorporated PA TFN membrane was fabricated via IP method.•The Ag NPs were released via in situ decomposing of Ag compound nanorods.•A wrinkled surface profile with high internal porosity structure was developed.•High water permeance (10.4 L m−2 h−1 bar−1) and high rejection (97.7%) were obtained.•High sustainability of anti-fouling/-biofouling properties was achieved.
Gallic acid is an active phenolic acid widely distributed in plants, and there is compelling evidence to prove its anti-inflammatory effects. NLRP3 inflammasome dysregulation is closely linked to ...many inflammatory diseases. However, how gallic acid affects the NLRP3 inflammasome remains unclear. Therefore, in the present study, we investigated the mechanisms underlying the effects of gallic acid on the NLRP3 inflammasome and pyroptosis, as well as its effect on gouty arthritis in mice. The results showed that gallic acid inhibited lactate dehydrogenase (LDH) release and pyroptosis in lipopolysaccharide (LPS)-primed and ATP-, nigericin-, or monosodium urate (MSU) crystal-stimulated macrophages. Additionally, gallic acid blocked NLRP3 inflammasome activation and inhibited the subsequent activation of caspase-1 and secretion of IL-1β. Gallic acid exerted its inhibitory effect by blocking NLRP3-NEK7 interaction and ASC oligomerization, thereby limiting inflammasome assembly. Moreover, gallic acid promoted the expression of nuclear factor E2-related factor 2 (Nrf2) and reduced the production of mitochondrial ROS (mtROS). Importantly, the inhibitory effect of gallic acid could be reversed by treatment with the Nrf2 inhibitor ML385. NRF2 siRNA also abolished the inhibitory effect of gallic acid on IL-1β secretion. The results further showed that gallic acid could mitigate MSU-induced joint swelling and inhibit IL-1β and caspase 1 (p20) production in mice. Moreover, gallic acid could moderate MSU-induced macrophages and neutrophils migration into joint synovitis. In summary, we found that gallic acid suppresses ROS generation, thereby limiting NLRP3 inflammasome activation and pyroptosis dependent on Nrf2 signaling, suggesting that gallic acid possesses therapeutic potential for the treatment of gouty arthritis.
Traditional resin exchange processes for the removal of heat-stable salt (HSS) from lean amine solutions have limited efficiency, and require large amount of alkali for regeneration, causing a ...serious negative impact on the sustainable environmental development. In this study, a new bipolar membrane electrodialysis (BMED) process was proposed to replace the original resin-based method for the removal of HSS from practical lean amine liquids (from a natural gas factory of PetroChina Company). The experimental conditions of current density, volumetric ratio, HSS concentration, and etc., were systematically investigated. It was found that a high HSS removal efficiency of up to 95.7% with an extremely low loss rate of the organic amine of down to 1.39% can be obtained, under the optimal current density of 60 mA/cm2. A continuous operation verified the long-term stability of BMED for a high-efficiency HSS removal rate of up to 80.3% after a 600-h duration. From the findings in this study, we develop a conceptual exploration describing the BMED process for the separation of HSS from practical desulfurization wastewater, beyond the lean amine liquids, offering a guidance for their potential industrial applications.
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•A zero-discharge process was proposed for the removal of heat-stable salt.•A variety of process conditions were explored for the impact of HSS separation.•The removal of HSS was over 95%, which is acceptable for industrial scale.
Mixed-matrix membranes (MMMs) have been drawing increasing attention due to the high permeability and high rejection capabilities for highly efficient wastewater treatment applications. Nonetheless, ...improving the water permeance while maintaining the high rejection capability is still an ongoing challenge for the practically state-of-the-art MMMs. Herein, a new class of poly(ether sulfone) (PES) based MMM containing metal–organic framework (MOF) nanofillers of HKUST-1 and blending with poly(methyl methacrylate-co-methacrylic acid) (PMMA-co-MAA) copolymer, designated as HKUST-1@mPES MMM, were developed for the highly efficient ultrafiltration (UF) process. In this study, the nanosized HKUST-1 nanofillers were removed by water dissolution as sacrificial templating materials, so that the additional nanovoids were deliberately generated throughout the dense polymer matrix. The introduction of PMMA-co-MAA copolymer facilitated the even dispersion of HKUST-1 nanofillers in a polymer matrix, by constructing the bridge connection between inorganic nanofillers and organic matrix. The resultant HKUST-1@mPES MMM exhibited a high pure water permeability (PWP) up to 490 L·m–2·h–1·bar–1, substantially reaching nearly 3 times higher than that of the mPES membrane without HKUST-1 nanofillers loading and maintaining a relatively high BSA rejection rate of 96% without obvious deterioration. The newly developed HKUST-1@mPES MMM thereby exhibited a comparable separation efficiency compared to the cutting-edge UF membranes reported so far. Overall, the nanovoid-generated approach provides new insight into developing advanced MMMs used for highly efficient water treatment applications.
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