查看更多>>摘要：The photocatalysis/persulfate (PS) hybrid system has proven to be a promising method for degrading organic pollutants from aqueous solutions. In this study, three MIL-88B(Fe) iron-based metal-organic framework (MOF) phases with different facet content were prepared and used both as photocatalysts and catalysts for PS activation to remove ibuprofen (IBP). The results showed that there was a close correlation between the exposed facets and the catalytic activity. MIL-88B(Fe)-1 (M88B1) with exposed {1 0 0} facets and proportionally more {1 0 1} facets showed the best catalytic activity. The optimum PS dosage used in this study was 60 mg/L. The presence of Cl , SO42, and NO3 all inhibited the degradation of IBP. X-ray photoelectron spectroscopy (XPS) showed that M88B1 possessed more Fe2+ than the other two MIL-88B(Fe) MOF phases, making it easier to generate active radicals through PS activation. The UV-vis diffuse reflectance spectra (DRS), photoluminescence (PL), and electrochemical analysis indicated that M88B1 possessed the highest light absorption, most active sites, and fastest charge transfer ability. Radical scavenging and electron spin resonance (ESR) experiments demonstrated that SO4 center dot, (OH)-O-center dot, O-2(center dot), and O-1(2) species participated in the IBP degradation process. Furthermore, density functional theory (DFT) calculations were performed to identify the crystallographic facets, band structure, and total density of states of MIL-88B(Fe) to further confirm the mechanism of MIL-88B(Fe) as a photocatalyst and a PS activator. This work provides new insights into the synergism between photocatalysis and persulfate activation by facet-controlled MOFs for environmental remediation. (C) 2021 Published by Elsevier Inc.
查看更多>>摘要：Enhancing the deposition of fragrance delivery systems contained in personal care products on target surfaces is crucial for increasing the longevity of scent, efficiently utilizing expensive functional compounds and limiting the generation of microplastics in domestic waste water. In this work, we designed and synthesized a new type of biomimetic macromolecules, chitosan-graft-L-lysine-L-DOPA (C-L-D), as a versatile biodegradable adhesion promoter to facilitate the deposition of biodegradable fragrance carriers on diverse surfaces including hair, cotton and skin. The C-L-D has hyperbranched chain architecture with many oligopeptide adhesive tentacles, each being a simple mimic of mussel adhesive proteins. It also exhibits unique amphiphilic characteristic. As a result, it could be facilely anchored on cargo-loaded poly(lactic-co-glycolic acid) nanoparticle surface via self-assembly in the particle preparation process. The C-L-D-modified nanoparticles show significantly higher deposition efficiencies than polyvinyl alcohol- and chitosan-coated particles when deposited on the target surfaces in different aqueous media as the lysine and DOPA units are capable of providing multi-noncovalent interactions, including electrostatic, polar, hydrophobic interactions, and bidentate hydrogen bonds, with the target surfaces, and possibly also inducing oxidative cross-linking. A much higher retention rate of the C-L-D-modified nanoparticles on cotton surface is also observed after washing with a soap solution, which could be attributed to the significant role played by bidentate hydrogen bonds. These findings suggest that C-L-D is a versatile biodegradable adhesion promoter and has the potential to be applied for various personal care applications and beyond. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：Hypothesis: Separations of particles and cells are indispensable in many microfluidic systems and have numerous applications in chemistry and biomedicine. The interface of aqueous two-phase system (ATPS) can act as a liquid filter. Under electric field stimuli, the selective transfer of targets across the liquid-liquid interface are expected for particles and cells separation. Experiments: The separations of particles and cells based on ATPS electrophoresis in a microfluidic chip were investigated. A systematical study of the mechanism of ATPS electrophoresis was performed first by employing polystyrene (PS) particles. Subsequently, the separations of particles and microalgae cells were demonstrated. Findings: The electrophoretic transfer of particles across the interface of ATPS is determined by multiparameters, including the strength of electric pulse, particle size, zeta potential, and hydrophobicity of the particle. The continuous separations of particles/cells can be achieved through the controllable transfer of target particles/cells across the interface under electric pulses in a microfluidic chip. By simply turning the magnitude of the applied electric pulse, the technique is suitable for different purposes, for example, the separations of particles and cells, purification of cells, and viability identification of cells. This tunable separation approach opens opportunities in multidimensional particle and cell sorting for the fields of seed selection of microorganisms, environmental assessment, and biomedical research. (c) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：The development of an environmental-friendly thermal insulation and flame retardant material has attracted widespread attention in modern architecture. In this work, a kind of novel aerogel composites were prepared by incorporation of Mg(OH)(2) coated hollow glass microspheres (HGM) into chitosan (CSA) matrix and then cross-linking by glutaraldehyde (abbreviated as CSA-HGM-Mg(OH)(2)). The as-prepared composite aerogel exhibits vertical directional channel with high porosity and excellent thermal insulation with a low thermal conductivity of 0.035 Wm (1) k (1). Besides, it shows excellent flame retardancy with a high limit oxygen index (LOl) value up to 50.8, which is one of the highest values among the most of flame retardants reported previously. Also, a very low peak heat release rate (pHRR) of 24.12 kW m (2) was obtained which makes the aerogel composite reaching UL-94 V-0 rating. Such results may be attributed to a synergy effect by combination of its abundantly porous structure derived from HGM to give a better thermal insulation and excellent nonflammability of CSA and Mg(OH)(2) to offer a superior flame retardancy. Taking advantages of its high mechanical strength, low cost materials, simple and scalable preparation method, CSA-HGM-Mg(OH)(2) aerogel composites may hold great potential for future thermal insulation and flame retardant applications. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：Due to the highly flexible reconfiguration of swarms, collective behaviors have provided various natural organisms with a powerful adaptivity to the complex environment. To mimic these natural systems and construct artificial intelligent soft materials, self-propelled colloidal motors that can convert diverse forms of energy into swimming-like movement in fluids afford an ideal model system at the micro-/ nanoscales. Through the coupling of local gradient fields, colloidal motors driven by chemical reactions or externally physical fields can assembly into swarms with adaptivity. Here, we summarize the progress on reconfigurable assembly of colloidal motors which is driven and modulated by chemical reactions and external fields (e.g., light, ultrasonic, electric, and magnetic fields). The adaptive reconfiguration behaviors and the corresponding mechanisms are discussed in detail. The future directions and challenges are also addressed for developing colloidal motor-based interactive soft matter materials and systems with adaptation and interactive functions comparable to that of natural systems. (c) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：Developing efficient catalytic systems to boost hydrogen evolution from hydrolytic dehydrogenation of ammonia borane (AB) is of broad interest but remains a formidable challenge since the widespread usages of hydrogen have been considered as sustainable solutions to ensure future energy security. Herein, we developed an alkaline ultrasonic irradiation-mediated catalytic system with O/N-rich porous carbon supported Ru nanoclusters (NCs) (Ru/ONPC) to considerably boost the catalytic activity for hydrogen production from the hydrolytic dehydrogenation of AB. The uniformly distributed sub-2.0 nm Ru NCs on the ONPC were demonstrated to be efficient catalysts to boost hydrogen generation from the hydrolytic dehydrogenation of AB with the synergistic effect between ultrasonic irradiation and alkaline additive without any additional heating. An ultrahigh turnover frequency (TOF) of 4004 min(-1) was achieved in the developed catalytic system, which was significantly higher than that of ultrasound-mediated AB hydrolysis without alkali (TOF: 485 min(-1)) and alkaline AB hydrolysis (TOF: 1747 min(-1)) without ultrasound mixing. The alkaline ultrasonic irradiation was beneficial for the cleavage of the O-H bonds in the attacked H2O molecules catalyzed by the Ru/ONPC and thus considerably boost the catalytic hydrogen generation from AB. This study provides a tractable and ecofriendly pathway to promote the activity toward AB hydrolysis to release hydrogen. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：Interfacial evaporation has recently received great interest from both academia and industry to harvest fresh water from seawater, due to its low cost, sustainability and high efficiency. However, state-of-the-art solar absorbers usually face several issues such as weak corrosion resistance, salt accumulation and hence poor long-term evaporation stability. Herein, a hydrophobic and porous carbon nanofiber (HPCNF) is prepared by combination of the porogen sublimation and fluorination. The HPCNF possessing a macro/meso porous structure exhibits large contact angles (as high as 145 degrees), strong light absorption and outstanding photo-thermal conversion performance. When the HPCNF is used as the solar absorber, the evaporation rate and efficiency can reach up to 1.43 kg m (2)h(-1) and 87.5% under one sunlight irradiation, respectively. More importantly, the outstanding water proof endows the absorber with superior corrosion resistance and salt rejection performance, and hence the interfacial evaporation can maintain a long-term stability and proceed in a variety of complex conditions. The HPCNFs based interfacial evaporation provides a new avenue to the high efficiency solar steam generation. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：Developing battery-supercapacitor hybrid devices (BSHs) is viewed as an efficient route to shorten the gap between supercapacitors and batteries. In this study, a composite hydrogel consisting of perylene tetracarboxylic diimide (PTCDI) and reduced graphene oxide (rGO) is tested as the anode for BSHs in the electrolyte of ammonium acetate (NH4Ac) with a record concentration of 32 molality (m). This water-in-salt electrolyte exhibits a wide electrochemical stability window of 2.13 V and high conductivity of 23.3 mS cm(-1) even at -12 degrees C. Molecular dynamics calculations and spectroscopic measurements reveal that a favorable water-acetate interaction occurs in a high concentration NH4Ac electrolyte. On the other hand, the study of electrode kinetics in 32 m NH4Ac demonstrates a high capacitive contribution to charge storage in PTCDI-rGO although an electrode redox reaction involves reversible enolization of carbonyl groups in PTCDI. This result suggests fast NH4+-ion intercalation kinetics in charge-discharge processes. Furthermore, the electrode performance is improved by optimizing the loading amount of rGO in composites. The best-performing composite electrode delivers the maximum capacity of 165 mAh g(-1) at 0.5 A g(-1) and sustains a great capacity retention of 66% at 8 A g(-1). Finally, an all-organic BSH device is tested in a broad temperature window from -20 to 50 degrees C and is well operated at 1.9 V regardless of operating temperatures. Due to the synergetic effect of splendid electrolyte properties and high anode capacities, BSH devices possess the maximum energy density of 12.9 Wh kg(-1) at the power density of 827 W kg(-1) and retain 74 % of the initial capacity after 3000 cycles at 1 A g(-1). Our study paves a novel route towards designing inexpensive and environmentally friendly BSH devices with high performances. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：Solar desalination is considered as a promising approach to solve the shortage of fresh water resources. In this work, inspired by the transpiration of trees, a self-floating and integrated bionic mushroom solar steam generator (BMSSG) is proposed for highly efficient water evaporation. A wooden strip is used to mimic the stipe of the mushroom for water transportation, meanwhile polyvinyl alcohol (PVA) modified graphene aerogels (GA) is used to imitate the pileus of the mushroom for photothermal conversion. After optimizing compositions of the aerogel and sizes of the wooden strip, a high evaporation rate of 1.67 kg m (-2) h (-1) is obtained, outcompeting most of other wood-based evaporators. Compared to traditional interfacial evaporation devices, BMSSG is an integrated structure without a thermal insulation layer and an absorbent wick, which not only increases the compactness that is good for stability and reliability, but also reduces the manufacturing cost. Moreover, the BMSSG can self-float on the water like a roly-poly. These advantages indicate that BMSSG will play a significant role in seawater desalination. The feasibility as well as stability and recyclability of the BMSSG for seawater desalination are demonstrated. This bioinspired design provides a low-cost and scalable SSG, which will have a profound impact in future practical applications. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：Phonon scattering by intrinsic defects and nanostructures has been the primary strategy for minimizing the thermal conductivity in thermoelectric materials. In this work, we present the effect of Isovalent substitution as a method to decouple the Seebeck coefficient and the thermal conductivity of antimony (Sb) substituted bismuth selenide (Bi2Se3). Transmission electron microscopy studies present the nanostructured Bi2-xSbxSe3 thermoelectric system represents the coexistence of hierarchical defect structure and dislocations. The observed giant reduction in thermal conductivity is due to the multi-scale phonon scattering caused by a combination of stacking faults, lattice dislocations and grain boundary scattering. This study reveals that a large number of dislocations about similar to 1.09 x 10(16) m(-2) are particularly effective at lowering thermal conductivity. We achieved one of the ultra-low thermal conductivity values (similar to 0.26 W/m K) for the maximized dislocation concentration. Moreover, Isovalent substitution provides a new avenue for the reduction in thermal conductivity and significant enhancement in the Seebeck coefficient of thermoelectric materials. (C) 2021 Elsevier Inc. All rights reserved.
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