Natural high-porous diatomaceous-earth based self-floating aerogel for efficient solar steam power generation

The application of solar steam generation in seawater desalination is an effective way to solve the shortage of fresh water resources.At present,many kinds of photothermal conversion materials have been developed and used as evaporators in seawater desalination.However,some evaporators need additional thermal insulation or water supply devices to achieve efficient photothermal conversion.In addition,their complex,time consuming and no scalable preparation process,high cost of raw materials and poor salt resistance hinder the practical application of these evaporator.Owing to its distinctive nanoporous structure,diatomite as fossilized single-cells algae diatoms is a promising natural silica-based material for seawater desalination.They are taken from sea and that makes true sense to use them in the sea.Herein,we report the first example of synthesis robust three-dimensional(3D)natural-diatomite composite by assembling polyaniline nanoparticles covered diatomite into the polyvinyl alcohol pre-treated melamine foam frameworks and demonstrate its application as new evaporator for seawater desalination.The porous framework does not only improve the sunlight scattering efficiency,but also offer large network of channels for water transportation.The inherent mechanism behind salt desalination process involves the absorption of water molecules on the surface of the internal silica micro-nano pores,and evaporation under the heat induced by the polyaniline absorbed sunlight.Meanwhile,the metal ions are segregated by many available pores and channels to achieve the self-desalting effect.The developed evaporator possesses the superiority of multi-stage pore structure,strong hydrophilicity,low thermal conductivity,excellent light absorption,fast water transportation and salt-resistant crystallization as well as good durability.The evaporation rate without an additional device is found to be 1.689 kg m^(-2)h^(-1)under 1-Sun irradiation,and the energy conversion efficiency is as high as 95%.This work creates a platform and develops the prospect of employing green and sustainable natural-diatomite composite evaporator for practical applications of seawater desalination.

Ultrafine polycrystalline titania nanofibers for superior sodium storage

Sodium ion batteries have a huge potential for large-scale energy storage for the low cost and abundance of sodium resources. In this work, a novel structure of ultrafine polycrystalline TiO2 nanofibers is prepared on nickel foam/carbon cloth by a simple vapor deposition method. The as-prepared TiO2 nanofibers show excellent performance when used as anodes for sodium-ion batteries. Specifically, the TiO2 nanofibers@nickel foam electrode delivers a high reversible capacity of 263.2 m Ahg^-1 at 0.2 C and maintains a considerable capacity of 144.2 m Ahg^-1 at 10 C. The TiO2 nanofibers@carbon cloth electrode also shows excellent high-rate capability, sustaining a capacity of 148 m Ahg^-1 after 20 0 0 cycles at 10 C. It is believed that the novel nanofibrous structure increases the contact area with the electrolyte and greatly shortens the sodium ion diffusion distance, and meanwhile, the polycrystalline nature of nanofibers exposes more intercalation sites for sodium storage. Furthermore, the density functional theory calculations exhibit strong ionic interactions between the exposed TiO2(101) facets and sodium ions, leading to a preferable sodiation/desodiation process. The unique structural features endow the TiO2 nanofibers electrodes great advantages in rapid sodium storage with an outstanding high-rate capability.

Fabrication and formation mechanism of closed-loop fibers by electrospinning with a tip collector

Electrospun nanofibers with designed or controlled structures have drawn much attention. In this study, we report an interesting new closed-loop structure in individual cerium nitrate/polyvinyl alcohol（Ce（NO3）3/PVA） and Na Cl/PVA fibers,which are fabricated by electrospinning with a nail collector. The electrospinning parameters such as voltage and Ce（NO3）3（or Na Cl） concentration are examined for the formation of the closed-loop structure. The results suggest that the increase of the spinning voltage or addition of Ce（NO3）3（or Na Cl） is favorable for the formation of the closed-loop structure, and the increase of loop numbers and the decrease of loop size. Further analyses indicate that the formation mechanism of the closed-loop fibers can be predominantly attributed to the Coulomb repulsion in the charged jets.

Zinc-catecholete frameworks biomimetically grown on marine polysaccharide microfibers for soft electronic platform

Integrating functional nanomaterials on nonplanar organisms has emerged as a rising technology,while significant mismatch would cause interface failure and poor durability.Herein,we demonstrate a facile strategy to assemble crystalline catecholate frameworks with honeycomb lattice on seaweed-derived polysaccharide microfibers,which is expected to form biomimetic connections and maintain durable stability.By physiological coagulation,well-aligned ZnO nanoarrays are tightly attached on alginate fibers,which is fractionally adopted as sacrifice for heteroepitaxial growth of zinc-catecholate frameworks(Zn3(HHTP)2).Benefiting from amplification effect of in-situ formed heterojunctions,promoted interfacial charge transfer is achieved,which allows for fabricating broadband photodetectors.Combined with high porosity for gas adsorption,the heteroepitaxial catecholate framework further enables its use as highly selective ppb-level triethylamine sensors.This work provides a promising strategy for heteroepitaxial growth of catecholate frameworks on organo-substrates and opens new applications in wearable sensor platform based on comfortable biofibers.

CoFe_2O_4/carbon nanotube aerogels as high performance anodes for lithium ion batteries

High-performance lithium ion batteries(LIBs) require electrode material to have an ideal electrode construction which provides fast ion transport, short solid-state ion diffusion, large surface area, and high electric conductivity. Herein, highly porous three-dimensional(3D)aerogels composed of cobalt ferrite(CoFe_2O_4, CFO) nanoparticles(NPs) and carbon nanotubes(CNTs) are prepared using sustainable alginate as the precursor. The key feature of this work is that by using the characteristic egg-box structure of the alginate, metal cations such as Co^(2+)and Fe^(3+) can be easily chelated via an ion-exchange process, thus binary CFO are expected to be prepared. In the hybrid aerogels, CFO NPs interconnected by the CNTs are embedded in carbon aerogel matrix, forming the 3D network which can provide high surface area, buffer the volume expansion and offer efficient ion and electron transport pathways for achieving high performance LIBs. The as-prepared hybrid aerogels with the optimum CNT content(20 wt%) delivers excellent electrochemical properties, i.e., reversible capacity of 1033 mAh g^(-1) at 0.1 A g^(-1) and a high specific capacity of 874 mAh g^(-1) after 160 cycles at 1 A g^(-1). This work provides a facile and low cost route to fabricate high performance anodes for LIBs.

Nitrogen/sulphur dual-doped hierarchical carbonaceous fibers boosting potassium-ion storage

The carbon materials as anode electrodes have been widely studied for potassium ion batteries(PIBs).However,the large size of potassium ions prevents their intercalation/deintercalation,resulting in poor storage behaviors.Herein,a novel design of N/S codoped hierarchical carbonaceous fibers(NSHCF)formed from nanosheets self-assembled by catalyzing Aspergillus niger with Sn is reported.The asprepared NSHCF at 600℃(NSHCF-600)exhibits a high reversible capacity of 345.4 m Ah g^(-1) at 0.1 A g^(-1) after 100 cycles and an excellent rate performance of 124.5 m Ah g^(-1) at 2 A g^(-1).The excellent potassium storage performance can be ascribed to the N/S dual-doping,which enlarges interlayer spacing(0.404 nm)and introduces more defects.The larger interlayer spacing and higher pyridinic N active sites can promote K ions diffusion and storage.In addition,the ex situ transmission electron microscopy reveals the high reversibility of potassiation/depotassiation process and structural stability.

Influences of the adsorption state of catalyst on the performance of DS-PEC for visible light driven water splitting

Adsorption state of catalyst on photoanode is an important factor on influencing the performance of dye-sensitized photoelectrochemical cells (DS-PECs) for water splitting. Photoanode TiO2(1 + 2) was assembled with Ru(bpy)(3) phosphoric acid derivative (complex 1) as photosensitizer and complex 2 as water oxidation catalyst to compare with photoanode TiO2(1 + 3). The photocurrent density of photoanode TiO2(1 + 3) with catalyst 3 synthesized with only one end fixing on the surface of TiO2 is about four-fold of the photoanode assembled with catalyst 2 fixing with two claws on the surface of TiO2. The phenomenon should be caused by the littery arrangement and shorter distance of catalyst 2 from the active center of catalyst to TiO2 on the surface of semiconductor which led to lowly efficient electron transfer. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved

Numerical Estimation of the Thermal Response of Thermal Protective Clothing-Air Gap-Human Skin Micro-system

Thermal protective clothing has been recognized as the primary shielding against emergency fire hazard and inflammable gas leakage. Therefore,the thermal response of human covered with thermal protective clothing under high temperature is the key work to investigate the thermal insulation of thermal protective clothing. A coupling model composed of thermal protective clothing,air gap and human skin is established and the temperature of the micro-system is numerically solved via the finite element method( FEM).Especially,the heat transfer of air gap located between clothing and human skin considering conduction and radiation is established while the human skin layers involve the effect of blood perfusion. Then the effect of thermophysical properties( thermal conductivity and volumetric capacity) of fabric and thickness of fabric and air on the thermal response of the micro-system is elucidated and compared.The results indicate that the volumetric heat capacity of fabric is the key parameter to affect the thermal shielding performance of thermal protective clothing,and the thicker fabric thickness and air gap thickness can improve the thermal protective properties of the micro-system.

In situ synthesis of FeS/Carbon fibers for the effective removal of Cr(Ⅵ)in aqueous solution

Iron sulfide(FeS)nanoparticles(termed FSNs)have attracted much attention for the removal of pollutants due to their high efficiency and low cost,and because they are environmentally friendly.However,issues of agglomeration,transformation,and the loss of active components limit their application.Therefore,this study investigates in situ synthesized FeS/carbon fibers with an Fecarrageenan biomass as a precursor and nontoxic sulfur source to ascertain the removal efficiency of the fibers.The enrichment of sulfate groups as well as the double-helix structure in i-carrageenan-Fe could effectively avoid the aggregation and loss of FSNs in practical applications.The obtained FeS/carbon fibers were used to control a Cr(Ⅵ)polluted solution,and exhibited a relatively high removal capacity(81.62 mg/g).T he main mechanisms included the reduction of FeS,electrostatic adsorption of carbon fibers,and Cr(Ⅲ)-Fe(Ⅲ)complexation reaction.The pseudo-second-order kinetic model and Langmuir adsorption model both provided a good fit of the reaction process;hence,the removal process was mainly controlled by chemical adsorption,specifically monolayer adsorption on a uniform surface.Furthermore,co-existing anions,column,and regeneration experiments indicated that the FeS/carbon fibers are a promising remediation material for practical application.

Effect of Irradiation Crosslinking on Polyethylene Terephthalate Flame-Retardant Fabric

Irradiation cross-linking of flame-retardant polyethylene terephthalate( FR-PET) fabric with the presence of trimethylolpropane triacrylate( TMPTA) was studied. Thermal gravimetric( TG) analysis,differential scanning calorimetry( DSC) and scanning electron microscopy( SEM) were used to analyze the effects of irradiation crosslinking on structure and property of FR-PET fabric with TMPTA. The cross-linking was promoted by the introduced sensitizer. The gel content was 5.94% at the lower dose of 90 kGy and it arrived at the highest level of 13.01% with the increased doses. There were no melt drips of FR-PET fabric after irradiation cross-linking while the flame retardance disappeared at the time of combustion. The melting temperature of irradiated fabric decreased and TG analysis showed that the onset temperature of degradation of FR-PET fabric and the amount of nonvolatile residue at 800℃ increased as the irradiation dosage increased,but it changed a little compared with the pure FR-PFT fabric. SEM photographs showed that the residue char of irradiated PET fabrics after vertical test remained the intrinsic crossed structure,and the enlarged graph showed that the char was uniformly distributed and it was tight honeycombs structure.

基于聚吡咯/蛭石/海藻纤维复合半导体材料的瞬态压阻传感器

电子皮肤、人机交互和健康监测等领域推动了柔性压力传感器的快速发展.然而,同时满足耐用和瞬态的需求对柔性压力传感器是一个巨大的挑战.本文开发了一种用于柔性瞬态压阻传感器的安全、耐受的聚吡咯/蛭石/海藻酸盐半导体框架.将带负电荷的蛭石纳米片插层到可生物降解的海藻酸盐织物中,进一步用高灵敏度的导电聚吡咯修饰.由此产生的多维框架实现了柔性传感器的稳定性,并且在使用寿命结束后可以在不留下电子垃圾的情况下逐渐降解.所获得的瞬态压阻传感器显示出了快速的响应时间(81/99 ms)和出色的抗疲劳性能.此外,我们开发了一种有效的机器学习模型用于人体动作识别和预测,准确率为100%.本工作为柔性瞬态电子学中有机-无机界面的设计提供了一种有前景的策略,并在基于舒适生物纤维的柔性平台中展现了广阔的应用前景.

How heteroatoms(Ge,N,P) improve the electrocatalytic performance of graphene:theory and experiment

The oxygen reduction reactions(ORR)play a crucial role in the electrochemical energy storage devices,such as fuel cell,metal-air batteries[1–3].However,their larger scale applications are hindered by the sluggish slow kinetics of the ORR.Up to now,platinum(Pt)-based catalysts are still known as the best

Interfacial energy barrier tuning of hierarchical Bi_(2)O_(3)/WO_(3) heterojunctions for advanced triethylamine sensor

Traditional triethylamine(TEA)sensors suffer from the drawback of serious cross-sensitivity due to the low charge-transfer ability of gas-sensing materials.Herein,an advanced anti-interference TEA sensor is designed by utilizing interfacial energy barriers of hierarchical Bi_(2)O_(3)/WO_(3) composite.Benefiting from abundant slit-like pores,desirable defect features,and amplification effect of heterojunctions,the sensor based on Bi_(2)O_(3)/WO_(3) composite with 40%Bi_(2)O_(3)(0.4-Bi_(2)O_(3)/WO_(3))demonstrates remarkable performance in terms of faster response/recovery time(1.7-fold/1.2-fold),higher response(2.1-fold),and lower power consumption(30℃-decrement)as compared with the pristine WO_(3) sensor.Furthermore,the composite sensor exhibits long-term stability,reproducibility,and negligible response towards interfering molecules,indicating the promising potential of Bi_(2)O_(3)/WO_(3) heterojunctions in anti-interference detection of low-concentration TEA in real applications.This work not only offers a rational solution to design advanced gas sensors by tuning the interfacial energy barriers of heterojunctions,but also provides a fundamental understanding of hierarchical Bi_(2)O_(3) structures in the gas-sensing field.

Concave Pt-Cu-Fe ternary nanocubes：One-pot synthesis and their electrocatalytic activity of methanol and formic acid oxidation

Concave nanostructures may be developed to improve the specific mass activity of a catalyst for formic acid and methanol electro-oxidation. In this work, we report the elctrocatalytic oxidation of methanol and formic acid in acid medium over concave Pt-Cu-Fe ternary nanocubes（NCs）, obtained by the galvanic exchange of Pt and Fe on Cu NCs. The concave Pt-Cu-Fe NCs exhibited improved electrooxidation performance contrasted to Pt-Cu NCs and purchased commercial Pt/C as demonstrated by their improved durability, lower onset potential, and more preferable anti-poisoning properties. These properties are believed to originate from the tailored concave structure of the catalyst and possible synergetic effects among the components of the Pt-Cu-Fe NCs.

A green MXene-based organohydrogel with tunable mechanics and freezing tolerance for wearable strain sensors

Conductive hydrogels have attracted considerable attention owing to their potential for use as electronic skin and sensors.However,the loss of the inherent elasticity or conductivity in cold environments severely limits their working conditions.Generally,organic solvents or inorganic salts can be incorporated into hydrogels as cryoprotectants.However,their toxicity and/or corrosive nature as well as the significant water loss during the solvent exchange present serious difficulties.Herein,a liquid-like yet non-toxic polymer-polyethylene glycol(PEG) was attempted as one of the components of solvent for hydrogels.In the premixed PEG-water hybrid solvent,polyacrylamide(PAAm) was in situ polymerized,overcoming the inevitable water loss induced by the high osmotic pressure of the PEG solution and achieving tailored water capacity.Interestingly,the mechanical strength( "soft-to-rigid" transition) and anti-freezing properties of organohydrogels can be simultaneously tuned over a very wide range through adjusting PEG content.This was due to that with increasing PEG in solvent,the PAAm chains transformed from stretching to curling conformation,while PEG bonded with water molecules via hydrogen bonds,weakening the crystallization of water at subzero temperature.Additionally,a highly conductive Ti_(3)C_(2)T_(x)-MXene was further introduced into the organohydrogels,achieving a uniform distribution triggered by the attractive interaction between the rich functional groups of the nanofillers and the polymer chains.The nanocomposite hydrogels demonstrate high electrical conductivity and strain sensitivity,along with a wide working temperature window.Such a material can be used for monitoring human joint movement even at low temperature and has potential applications in wearable strain sensors.

Defect promoted photothermoelectric effect in densely aligned ZnO nanorod arrays for self-powered position-sensitive photodetection

Sustainable light energy from ambient environment has attracted particular attention to meet the evergrowing need of small-scale electronics.The modulation of intercorrelated thermal and electronic transport is one of the crucial aspects for reliable photothermoelectric electronics.Herein,a defectpromoted photothermoelectric effect is demonstrated in densely aligned ZnO nanorod array with rich lattice defects.The defect-rich ZnO device delivers high electrical conductivity and large Seebeck coefficient to enable significant improvement of photothermoelectric energy conversion and self-powered photodetection.The position sensitivity reaches approximately 0.19 mV mm^(-1),and the temperature gradient induced electric field makes up for the suppression in the photothermoelectric process.The synergism between intrinsic defects and extra temperature field plays an important role in promoting the photothermoelectric properties of dense ZnO nanorod array.This study is interesting for interpreting the thermo-phototronic phenomena as well as demonstrating the possibility of defect engineering and phonon engineering to enable highly efficient light energy scavenging and self-powered photodetection.

一种用于可穿戴传感器的超柔性、透明、自粘附、可自愈、抗冻和长期稳定冷冻水凝胶

软体器件领域亟需多功能水凝胶,然而,其复杂的功能成分在实际应用中存在安全和环境隐患.在本研究中,单一氯化锂盐在构建冻融聚乙烯醇水凝胶的多层次结构中同时发挥多重作用,激发其前所未有的多功能性和长期稳定性.(1)在冷冻过程中,抗冻盐氯化锂抑制了冰晶的生长,由于冰晶对分子链的排异作用减弱,聚合物分子链靠近程度较弱,实现了分子链网络的非晶化及自由羟基的部分释放.(2)由于氯化锂的水合作用,自由水分子的选择性挥发不仅使高分子网络密集化,同时赋予水凝胶长期稳定性.(3)氯化锂的加入也赋予水凝胶固有特性.因此,最终所得聚乙烯醇水凝胶具备多功能性,包括卓越的柔性(杨氏模量为18.8 kPa)、延展性(704%)、透明度(84%)、粘附性、自愈性、抗冻性(-43℃)和长期稳定性(5个月后宽度和厚度分别为初始尺寸的95%和87%).本研究证明了单一冷冻水凝胶在可穿戴传感器中的应用.考虑到独特的多层次结构及多功能性,预计新一代聚乙烯醇水凝胶将为各种柔性设备提供更多的机会.

Self-assembly of carbon nanomaterials onto carbon fiber to improve the interfacial properties of epoxy composites

The interfacial property of carbon fiber(CF)reinforced composites is crucial to facilitate the application of high-strength composites.Utilizing the electrostatic and hydrogen bond properties of diazo resin,carbon nanotubes(CNTs)and graphene oxide(GO)could be quickly grafted onto the surface of the CF via the layer-by-layer self-assembly technique.The results showed that CNTs and GO were uniformly coated onto the CF surface,and the chemical activity and roughness of the modified CF surface were improved signif-icantly.The modified CF surface can significantly augment the interaction between the epoxy resin and the fiber.Remarkably,due to the good interfacial property,the impact performance of the composites re-inforced with the nanomaterial-modified CF was improved obviously.In addition,the interface properties of the composites are studied in depth.This method is expected to achieve rapid surface modification of carbon fiber.

Tumor Photothermal Therapy Employing Photothermal Inorganic Nanoparticles/Polymers Nanocomposites

The past decade has witnessed the booming developments of the new methodologies for noninvasive tumor treatment, which are considered to overcome the current limitation of low treating efficacy, high risk of tumor recurrence, and severe side effects. Among a variety of novel therapeutic methods, photothermal therapy, employing nanometer-sized agents as the heat generators under near-infrared(NIR) light irradiation to ablate tumors, gives new insights into noninvasive tumor treatments with minimal side effects. Although many nanomaterials possess photothermal effects, inorganic nanoparticles and polymers are the most competitive alternatives considering the high photothermal performance and good biocompatibility. In this review, we summarized the tumor photothermal therapy using the nanocomposites composed of inorganic nanoparticles and polymers. Extinction coefficient and photothermal transduction efficiency are the two main factors to evaluate the photothermal performance of nanocomposites in vitro. Considering the improvement in the stability,biocompatibility, blood circulation half-life, and tumor uptake rate after polymer coating, these nanocomposites should be designed with inorganic core and polymer shell, thus improving the tumor treating efficacy in vivo. Such structure fulfills the requirements of high photothermal performance and good bio-security, making it possible to achieve complete ablation for shallow and small tumors under the safe limitation of NIR laser power density.

Highly Efficient Photocatalytic Remediation of Simulated Polycyclic Aromatic Hydrocarbons （PAHs） Contaminated Wastewater under Visible Light Irradiation by Graphene Oxide Enwrapped Ag3PO4 Composite

Effective removal of polycyclic aromatic hydrocarbons （PAHs） from wastewater before their discharge into the environment is an ever pressing requirement. In this study, for the first time, simulated PAHs contaminated wastewater was photocatalytically remediated with graphene oxide （GO） enwrapped silver phosphate as visible light-driven photocatalysts. The GO/Ag3PO4 photocatalysts exhibited superior photocatalytic activity and stability compared with pure Ag3PO4, g-C3N4 and TiO2 （P25）. The degradation efficiency of naphthalene, phenanthrene and pyrene could reach 49.7%, 100.0% and 77.9%, rspectively within 5 min irradiation. The apparent rate constants of photocatalytic degradation of 3 wt% GO/Ag3PO4 composRe photocatalyst were 0.14, 1.21 and 2.46 rain^-1 for naphthalene, phenanthrene and pyrene, respectively. They were about 1.8, 1.5 and 2.0 times higher than that of pure Ag3PO4, and much higher than that of g-C3N4 and TiO2. Meanwhile, the efficiencies of 44.6%, 95.2% and 83.8% were achieved for naphthalene, phenanthrene and pyrene degradation even after 5 times of recycling in the GO/Ag3POa-PAHs photocatalysis system. Reactive species of O2^- and h^＋ were considered as the main partici- pants for oxidizing naphthalene, phenanthrene and pyrene.