•Synthesized three catalysts with different crystal structures and morphologies.•The current density of 10 mA cm−2 at an overpotential of 73.97 mV, with a tafel slope of 59.02 mV dec−1.•The superior ...hydrogen evolution performance of the phosphorized material was verified through DFT calculations.
This article elucidates the synthesis of NiMoO4-based catalysts with different arrays and crystal structures, including nanowires (nw), nanoplates (ns), and nanocolumns (nc). Subsequently, a high-temperature phosphorization method was employed to generate the corresponding P-NiMoO4 catalysts. The study investigates the structural evolution of the catalysts and changes in the active species under operational conditions. Concurrently, density functional theory (DFT) calculations provide a more in-depth description of the HER reaction mechanism, considering d-band centers and adsorption energies. Experimental results demonstrate that phosphorized NiMoO4 with a nanowire array structure and crystal structures of NiMoO4 and MoO3 exhibit the optimal HER performance, displaying superhydrophilic and underwater superaerophobic behaviors. The hydrophilic contact angle is 0°, and the aerophobic contact angle is 156.8° This array electrode achieves a current density of 10 mA·cm−2 at an overpotential as low as 73.97 mV. The experiments indicate that through doping and morphology control engineering, catalytic performance can be further synergistically enhanced, providing a new perspective for preparing HER catalytic electrodes with potential applications.
Display omitted
The oil and bacteria adhesion during membrane separation process brings great challenges to the operation costs and membrane service life. Meantime, the strong chemical corrosion in sewage seriously ...limits the durability of membrane as well. Herein, a facile strategy is developed for fabricating highly stable and efficient zwitterionic nanofibrous membrane (NFM) with self-cleaning feature via the combination of in-situ cross-linking of poly (sulfobetaine methacrylate) (PSBMA) and electrospun poly (ether sulfone) (PES) nanofibers. Owing to the introduction of zwitterionic functional groups, the PSBMA/PES NFM exhibits superior antifouling ability (over 3 cycles of crude oil fouling/self-cleaning and up to 7 days of bacteria adhesion/repelling tests). Moreover, the membrane also presents remarkable chemical stability in acidic, alkaline and salty environments; and exhibits excellent separation performance for both layered oil/water mixture and oil-in-water emulsion as well. Furthermore, the membrane is capable to remove bacteria during the continuous oil/water mixture separation. Overall, the proposed strategy provides a new perspective into developing long-term antifouling membrane materials for complicated oily wastewater remediation in various corrosive environments.
Display omitted
•Self-cleaning zwitterionic nanofibrous membranes (NFMs) are prepared.•The NFMs can resist not only crude oil fouling but also bacteria adhesion.•The NFMs present highly-efficient oil/water separation performance.•The NFMs show great chemical stability in acid, alkaline and salty environments.
•The Janus nanofibrous membrane was successfully fabricated by a bottom-up electrospinning strategy.•The nanofibrous membrane exhibited robust asymmetric wettability.•The Janus nanofibrous membrane ...could efficiently separate various oil–water emulsions driven solely by gravity.
Superwettable membranes with superhydrophilicity/underwater superoleophobicity (SHL/UWSOB) or hydrophobicity/underoil superhydrophobicity (HB/UOSHB) are considered critical components in the chemical industry. However, despite the unique wettability of these membranes, there are still challenges in meeting the needs of the developing society. Herein, a Janus nanofibrous membrane with a special micro-nanostructure was constructed by a bottom-up electrospinning strategy using two different precursors: zeolitic imidazolate framework-8-polyacrylonitrile/N,N-dimethylformamide (ZIF-8-PAN/DMF) and candle soot-polyacrylonitrile/N,N-dimethylformamide (CS-PAN/DMF). The PAN@ZIF-8 nanofibrous membrane exhibited HB/UOSHB, with water contact angles higher than 150° in oils, whereas the PAN@CS nanofibrous membrane displayed favorable SHL/UWSOB, with oil contact angles greater than 151° in water. Simultaneously, the resulting Janus nanofibrous membrane exhibited excellent rejection rate (99.1%) towards various oil–water emulsions and a high flux of up to 1720 ± 20 L m−2h−1 driven only by gravity. The as-prepared Janus membrane was cycled five times without compromising the flux and rejection rate, demonstrating its satisfactory cycling stability. Comparative analysis demonstrated that the comprehensive separation performance of the resulting Janus nanofibrous membrane was superior to that of current homogeneous or other Janus membranes. More importantly, the as-prepared Janus membrane exhibited favorable chemical stability under harsh conditions (acidic and alkaline environments). This study presents a facile and efficient method for constructing a performance-stabilized Janus membrane, which can be utilized for multiple applications, such as oil–water separation, osmotic gasification, and seawater desalination.
Display omitted
•A unique 1D/2D hierarchical structure is successfully constructed.•The catalyst exhibits superhydrophilicity and superaerophobicity.•The as-prepared catalyst displays outstanding ...performance for HER and UOR.
Utilizing the thermodynamically favorable urea oxidation reaction instead of the anodic oxygen precipitation reaction is an alternative pathway for the energy-saving hydrogen production. Therefore, it is significant to explore advanced electrocatalysts for both HER and UOR. In this work, a dendritic heteroarchitectures of 2D CoMoO4 nanosheets deposited on 1D CoP nanoneedles (CoP/CoMoO4-CC) was fabricated as bifunctional electrocatalyst. 1D CoP nanostructure with fast charge transport pathways and 2D CoMoO4 nanostructure with large specific surface area and short paths for electron/mass transport. The unique morphology endows the superhydrophilic and superaerophobic properties, allowing for the rapid contact with the reactants and rapid removal of surface-generated gases. As a result, the CoP/CoMoO4-CC shows efficient bifunctional activity. This work offers a new avenue to rationally design bifunctional electrocatalysts for large-scale practical hydrogen production.
N, S and O doped Co/CoO/Co9S8@carbon derived from metal-organic framework with superhydrophilicity was prepared for efficiently activate PMS to degrade SMX.
Display omitted
•Lamellar ...Co/CoO/Co9S8@NSOC has been synthesized by calcinating a Co-MOF containing N,S,O-donor ligands.•SMX removal efficiency was 91.85% after 2 min with a high rate constant of 1.31 min−1.•Multiple cobalt species, hetero-atom doping, superhydrophilic surface contribute to the high ability of PMS activation.•The catalyst was loaded on the membrane and sponge to utilize in the flowing and static system, respectively.
Herein, a N,S,O-doped Co/CoO/Co9S8@carbon hybrid (Co/CoO/Co9S8@NSOC) has been constructed by calcinating a Co-based metal–organic framework (Co-MOF) with 4,4-bipyridine and 2,5-thiophenedicarboxylic acid as linkers. Co/CoO/Co9S8@NSOC exhibited a high and recycled catalytic efficiency for peroxymonosulfate (PMS) activation to degrade sulfamethoxazole (SMX, 20 mg/L) with a reaction rate of 1.31 min−1, which was 5.2 times than that of Co-MOF. The catalytic behavior should be attributed to the rich active sites, lamellar morphology, superhydrophilicity, and magnetism. Furthermore, the Co/CoO/Co9S8@NSOC was immobilized on a filter membrane (CMFM) to adapt to the flowing system, which could recycle 20 times without losing activity. To employ in a large-scale static environment, the Co/CoO/Co9S8@NSOC was loaded on the commercial sponge (CoSPG). In a 50 L water tank, the CoSPG realized to decompose 160 mg/L SMX solution with 37 h and had long-term stability over 10 days. Notably, the PMS cost of treating one ton of wastewater is only $0.34, indicating a huge industrial application value.
•A copper foam with negative charge and tortuous permeation channels was prepared.•The separation efficiency of the foam for dyes such as MB was as high as 99.93%.•Due to the large pore size, the ...permeate flux of the foam reaches 1671 L m-2h−1.•The foam has selective separation capability for mixed cationic dye wastewater.•Molecular dynamics simulations were used to explain the separation mechanism.
Rapid and efficient separation of dyes from water is a formidable challenge due to the trade-off between separation selectivity and permeability. Here, a novel superhydrophilic copper foam (CF) enabling the rapid and efficient filtration of cationic dyes from water is reported. The fabrication involves brushing a coating consisting of attapulgite (APT), poly(vinyl alcohol) (PVA), TiO2 and glutaraldehyde (GA) onto copper foam and then heating. The obtained copper foam (CF-PVA/GA@APT/TiO2) is superhydrophilic and negatively charged with dye adsorption capability. The interconnected cage-shaped porous structure endows the foam with long tortuous permeation channels and large pore size. It is able to separate various cationic dyes with a separation efficiency reaching to 99.93 % and a permeation flux up to 1671 ± 189 L m-2h−1 under gravity. Furthermore, the CF-PVA/GA@APT/TiO2 can realize the selective separation and recovery of various cationic dyes from rhodamine B (RhB)-mixed dye solutions. Molecular dynamics-based computational modeling and experimental studies revealed that the interaction energy between the surface of CF-PVA/GA@APT/TiO2 and methylene blue (MB) is much stronger than that of the former and RhB, leading to adsorption of MB in the permeation channel, while RhB gradually migrates through the permeation channel and passes through the channel with water. The tortuous permeation channels of CF-PVA/GA@APT/TiO2 increase the contact area and absorption opportunities for cationic dye molecules on the surface, and its large pore size maintains the filtration flux. These properties provide the as-prepared foam with excellent potential applicability for industrial dye wastewater treatment.
Display omitted
•A Ru/MXene 3D electrode features both superaerophobicity and superhydrophilicity.•The hybrid electrode shows superior HER performance in alkaline media.•It affords a low voltage of ...1.53 V at 10 mA/cm2 for overall water splitting.•The synergy between Ru and Ti3C2Tx during HER is revealed through DFT calculation.•The departure of H2 bubbles is investigated in real time through a PIV system.
Synergetic control of active sites, electrolyte wetting and gas releasing is of vital importance for efficient electrocatalysts in water-splitting. Herein, a Ru/MXene 3D electrode, featuring both superaerophobicity and superhydrophilicity, is first synthesized on porous Ni foam with the aid of Ti3C2Tx nanosheets. The Ru/c-Ti3C2Tx/NF achieves the current densities of 10, 100, 500, 1000 mA/cm2 at overpotentials of 37, 113, 219 and 320 mV respectively, with the Tafel slope of 60 mV/dec for hydrogen evolution reaction in alkaline media. It remains stable at 100 mA/cm2 during continuous electrolysis of 12 h. The Ru/c-Ti3C2Tx/NF demonstrates excellent overall water splitting performance, affording a low voltage of 1.53 V at 10 mA/cm2. In combination with DFT calculation, it illustrates that the enhanced HER performance of Ru/c-Ti3C2Tx/NF attributes to the synergetic modulation of Ru and Ti3C2Tx in the process of H2O dissociation and subsequent H2 formation, as well as superior wettability and rapid gas departure.
•Recent progress on oil/water separation ENs membranes is summarized.•Relationship between membrane characteristics and performance is highlighted.•Challenges and perspectives in oil/water separation ...ENs membranes are discussed.
Membrane separation technology has been considered as the most promising approach for effectively treating oily wastewater and oil-contaminated water due to its flexibility in operation and high efficiency. Among various techniques for the membrane fabrication, electrospinning with advantages of ease in mass production and potential incorporation of other functional materials on the nanoscale surface has gained widespread interest for the preparation of novel nanofibrous membranes with selective wettability, rational pore structure and high specific surface area. Numerous superantiwetting or superwetting electrospun nanofibrous membranes with good oil/water separation performance have been extensively reported in recent decades. In this review, the recent progress in the state-of-the-art electrospun nanofibrous membranes including superhydrophobic membranes, superhydrophilic membranes and intelligent membranes is highlighted and discussed, followed by challenges and perspectives presented on the potential application of electrospun nanofibrous membranes in the separation of oil/water emulsions. This review article would provide an in-depth insight into fabrication strategies of more effective electrospun nanofibrous membranes for the oil/water separation process.
PDF
