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This study synthesized nFe0 on the substrate of porous organic polymer (POM) which was prepared by glutaraldehyde and melamine. The POM-nFe0 composites were characterized by scanning electron microscopy, Brunner–Emmet–Teller, Fourier transform infrared spectrum, thermogravimetric analysis, powder X-ray diffraction, and X-ray photoelectron spectroscopy. The introduction of POM contributed to enhance the stability of U(IV) nanoparticles which is liable to be oxidized to mobile U(VI) under aerobic condition. According to the batch experiment, the maximum U(VI) removal capacity of POM-nFe0 was 230 mg/g, which shows great potential in wastewater treatment.

Nd:BiVO4 nanocrystals were synthesized by an effective and simple approach. Nd was incorporated into BiVO4 host to enhance electronic conductivity and lithium-ion diffusion kinetics, thus promoting the electrochemical performance. When employed as anode materials in lithium-ion batteries, a good cycling stability and high capacity of ~611 mAh g−1 at 100 mA g−1 were delivered. The work can be extensively employed for fabricating other electrode materials and promoting the electrochemical performance in energy storage correlative domains.

The modification and tuning features of nanostructured films are of great interest because of controllable and distinctive inherent properties in these materials. Here, nanocrystalline MoS2 films were fabricated on the stainless steels by a radio frequency magnetron sputtering at ambient temperature. X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and Raman scattering spectroscopy were used to study the chemical state, chemical composition, crystal structure and vibrational properties of the fabricated MoS2 films. The bias voltage dependent structural evolution and its influence on the optical properties of MoS2 nanocrystalline films were systematically investigated. Besides, the residual stresses of MoS2 nanocrystalline films were explored by employing sin2ψ approach. X-ray diffraction demonstrates that the nanocrystalline MoS2 films have single-phase hexagonal crystal structure. All MoS2 films are polycrystalline in nature. The bandgap values are found to be intensively dependent on bias voltage. Our findings show that the nanocrystalline MoS2 films with different physical properties and intense quantum confinement effect can be realized through adjusting bias voltages. This work may provide deep insight for realizing transitional metal dichalcogenide-based nanostructured film optoelectronic devices with tunable physical properties through a traditional, very cost-effective, and large-scale fabrication method.

With the development of nuclear energy, large amounts of radionuclides are inevitably released into the natural environment. It is necessary to eliminate radionuclides from wastewater for the protection of environment. Nanomaterials have been considered as the potential candidates for the effective and selective removal of radionuclides from aqueous solutions under complicated conditions because of their high specific surface area, large amounts of binding sites, abundant functional groups, pore-size controllable and easily surface modification. This review mainly summarized the recent studies for the synthesis, fabrication and surface modification of novel nanomaterials and their applications in the efficient elimination and solidification of radionuclides, and discussed the interaction mechanisms from batch experiments, spectroscopy analysis and theoretical calculations. The sorption capacities with other materials, advantages and disadvantages of different nanomaterials are compared, and at last the perspective of the novel nanomaterials is summarized.

Silica nanoparticle antireflection films are essential for the development of high-power laser systems because of their high laser damage threshold in ultraviolet (e.g., 351 nm or 355 nm). However, most laser damage reports focus on the films standing on substrates, and the intrinsic laser damage behaviors of the silica nanoparticle films are poorly understood due to the influence of the substrates. Here, we investigate the ultraviolet laser damage behaviors of the freestanding silica nanoparticle films. We find that silica nanoparitcle films demonstrate higher laser damage threshold than the fused silica substrates under the irradiation of 355-nm laser. For the films on the fused silica substrates, the laser damage is caused by the substrates. In the case of freestanding films, laser-damage resistance is strongly dependent on the film thickness and the amount of organic groups in the films. The laser damage threshold increases from 103 to 159 J/cm2 @ 355 nm with decreasing the film thickness from 322 to 31 nm. In addition, removal of organic groups from the films results in higher laser damage threshold. Our findings provide insight into the laser damage behavior of the silica nanoparticle films and foreshow a possible way to improve the laser-damage resistance.

Optical coatings with controllable ultralow refractive indices are of profound significance in optical areas. However, it remains a challenge to fabricate such coatings using a simple method. Here we develop an effective and simple approach to create ultra-low-index coatings. This approach was based on a modified sol-gel process, with a key process that involved the aggregation of silica nanoparticles via the addition of a polymer surfactant (e.g., polyvinylpyrrolydone) in sols before coating. The approach involves three steps: the synthesis of silica sols under ammonia catalysis in ethanol (Stober method), the addition of polyvinylpyrrolydone in the silica sols to induce the aggregation of the silica nanoparticles, and the formation of ultra-low-index coatings by depositing the aggregated silica sols on substrates. Through varying the aggregation extent, this approach produced coatings with controllable refractive indices ranging from 1.17 to 1.07. To the best of our knowledge, the minimum index value of 1.07 from our coating is among the lowest refractive indices ever reported. The ultra-low-index coatings demonstrated excellent optical properties, with which perfect quarter-wavelength antireflection coatings (maximum transmittance ∼100%) and broadband antireflection coatings (transmittance >98% from 400 to 1100 nm) can be prepared. One advantage of the antireflection coatings is that their transmission is less dependent on the refractive index and the thickness of the stacking layer, which make it promising in large-scale production. Moreover, the coatings can be made hydrophobic (water contact angle 136°) by exposing the coatings to a hexamethyldisilazane atmosphere, exhibiting high environmental stability in a humid environment. The aggregation of silica nanoparticles in sol-gel processes provides a scalable alternative to the current approaches for creating ultra-low-index coatings.

Uranium extraction from seawater provides the potential for a long-term green fuel supply for nuclear energy. However, the successful extraction of uranium from seawater is challenging because of the low uranium concentrations in seawater. Herein, we report poly(acrylamidoxime-co-acrylic acid) brush (PAO-co-AA)-based adsorbents that can highly efficiently extract and recover uranium from seawater. The PAO-co-AA-grafted fibers were fabricated by grafting of acrylonitrile and tert-butyl acrylate on poly(vinyl chloride) fibers via ARGET–ATRP method, followed by amidoximation and hydrolysis. The ARGET–ATRP method allowed for the synthesis of controllable polymer brushes with various grafting degrees (665–5908%) and thicknesses (15.1–56.3 µm) by varying the monomer concentrations during grafting. The uranium adsorption capacities of the grafted fibers were strongly affected by the grafting degree but independent of the surface area. The uranium adsorption capacities increased from 79 to 370 mg g−1 as the grafting degree increased from 665 to 3749%. The high adsorption performance can be attributed to the stretching of the polymer chain in the polymer brushes, which allows for full access of uranium ion to uranium-binding groups. The adsorbents demonstrated high uranium adsorption capacity of 5.4 mg g−1 using natural seawater in a batch adsorption mode after contact of 27 days, which is higher than that of most other adsorbents. The findings provide a new insight into the relationship between the structure and adsorption property and foreshadow the potential to use polymer brush-based adsorbents for uranium extraction from seawater.

Uranium recovery from seawater offers a promising route for producing scalable and sustainable nuclear energy because the world’s oceans contain hundreds of times more uranium than lands. A current adsorption method presents limitations including low extraction capacity and slow extraction kinetics, making realistic implementation impractical. Here we develop an electrochemical extraction approach that demonstrates high extraction capacity and fast extraction kinetics in uranium recovery. In the electrochemical approach, chitosan-functionalized electrodes were used to offer surface specific binding to uranyl ions; voltages were then supplied to attract the ions to the electrode and induce electrodeposition of uranyl ions to form charge-neutral uranium species. The electrodeposition approach demonstrated nearly 8 times higher uranium extraction capacities and 3 times faster extraction rates than the current adsorption method in uranium-spiked seawater. Because of the excellent uranium extraction performanc...

This paper studied the irradiation behavior of Nd2Zr2O7 ceramics under 2.0 MeV Xe20+ irradiation to high fluences from 4.08 × 1013 ions/cm2 to 5.28 × 1016 ions/cm2. Phase transformation, from pyrochlore to fluorite and finally to amorphization, have been discovered. In addition, the amorphous fraction increases with enhanced fluences, whereas it decreases with growing depth. Slight changes in Raman spectroscopy indicates that cation disordering is the mainly induced disordering. Obvious microtopography change but homogeneous element distribution have been observed through SEM-EDX. The HRTEM-SAED test verifies the irradiation induced order-disorder transition and amorphization. Our work could offer a set of detailed data for evaluating pyrochlores structural solidified body holding with nuclear waste.

In this paper, spark plasma sintering (SPS) was utilized to prepare simulated waste form intending to deal with high-level radioactive waste in a much fast way. Using Nd as a surrogate for trivalent actinides, a series of compositions with the general formula Gd2-xNdxZr2O7 (0.0 ≤ x ≤ 2.0) were fabricated and characterized. The phase structure, micro-morphology and density were investigated as a function of Nd content. The results show that Gd2-xNdxZr2O7 ceramics with x < 0.8 adopt fluorite structure, while the solid solutions with x ≥ 0.8 exhibit pyrochlore structure. SEM images reveal that all the samples prepared by SPS are irregularly shaped with a dense microstructure. Moreover, the density of samples decreases with increasing Nd content, and the SPS sintered ceramics is much higher in density than conventionally obtained ones.

Since Nd3+ and Ce4+ are usually taken as surrogates for the trivalent and tetravalent actinides, respectively, simulated nuclear waste form Nd2Ce2O7 and the potential host matrix Gd2Zr2O7 were studied in details to get a better understanding of the radiation stability of fluorite related compounds at the ultimate loading capacity. Both compounds were fabricated by traditional solid state process and irradiated with 2 MeV Xe20+ ions with dose of 0.072–91.17 dpa at room temperature. XRD results demonstrate the final fluorite phase in both compounds and their slight lattice swelling (about 0.35%) after irradiation for 91.17 dpa. Raman spectra indicate an obvious disordering of both compounds, while TEM analysis reveals atom disordering in Gd2Zr2O7 and amorphization in Nd2Ce2O7.

Proper disposal of nuclear waste with multi-nuclides and multi-valence is still challenge. A series of (Mo, Ru, Pd, Zr) tetra-doped Gd2Zr2O7 ceramics were studied to understand the microstructure and performance evolution of nuclear waste forms that immobilised simulated waste after trialkyl phosphine oxides (TRPO) process. The structure of as-obtained samples were tested by X-ray diffraction, Raman, scanning electron microscope, electron back-scattered diffraction, and energy-dispersive X-ray spectroscopy, while the mechanical and chemical performance were characterised by Vickers hardness and aqueous leaching method. The results indicate that the mechanical behaviour are closely linked with the phase structure, and the highest Vickers hardness is obtained at the phase turning point. The leaching results show that the normalised leaching rate (LR) of the doped elements decrease in the order of Mo, Ru, Pd, Zr. After reaching equilibrium, their LR are as low as 4.12 × 10−4 g·m−2·d−1, 1.50 × 10−5 g·...

Zircon was employed to immobilize simulated tetravalentactinide nuclide (Ce4+). Zr1−xCexSiO4 (0≤x≤0.10) ceramics were synthesized and their chemical durabilities were investigated systematically. The effects of pH and temperature on the chemical durability of the as-prepared compounds were investigated using the MCC-1 static leaching test, and their coupling effects were also explored. It was found that the normalized release rates of Ce in deionized water and alkaline solutions (pH=10) were smaller than those in acid solutions (pH=4). At a certain pH value, the normalized release rate of Ce (LRCe) increased with the temperature in the initial period. However, the leaching progress almost reached a balance after 14 days, and both of the pH and the temperature had slight impact on the leaching of Ce element. Moreover, the LRCe were below 10−5 g/m2/d after 42 days, which was lower than those of other nuclear waste forms in all discussed leachates.

It is necessary to study the self-irradiation effects of nuclear waste forms under α-decay in the long term storage. In the present work, accelerated irradiation experiments were performed on (Gd 1-4 x U 2 x ) 2 (Zr 1- x U x ) 2 O 7 ( x = 0, 0.10, 0.14) samples using 0.5 MeV alpha-particle irradiation at fluences ranging from 1 × 10 14 to 1 × 10 17 ions/cm 2 at room temperature. Irradiation induced microstructural evolution was examined by grazing incidence X-ray diffraction (GIXRD), Raman spectroscopy and Field-emission scanning electron microscopy (FESEM). The results show that the main crystal structure is kept, however, weaker structural ordering is leaded as a result of intensified irradiation. And the radiation resistance is enhanced by the growing uranium content in the discussed range. Moreover, the irradiation effects as a function of depth have been discussed. Raman spectra reveal that the vibration intensity of atomic bonds are changed due to increased irradiation. In addition, the microtopography and element distribution have been kept after irradiation.

Polymer brushes exhibit functionalities useful for a large number of applications. Often these functionalities only emerge when the polymer brushes have a desired thickness. Here, a significant breakthrough is achieved in the synthesis of ultra-thick polymer brushes using polymer initiators in the approach of surface-initiated atom transfer radical polymerization, yielding polymer brushes with a controllable thickness up to 15.1 µm. This is reportedly the thickest polymer brush ever synthesized. This approach is applicable for several monomers such as acrylonitrile, methyl acrylate, and styrene, and for other types of polymer substrates such as fibers.

Broadband antireflection coatings via sol-gel processes have find wide applications in a variety of optical areas. However, to adjust refractive indices of coatings, most sol-gel methods involved complicated processes that modify the microstructures of sol particles. Here, we find that ammonia treatment of the sol-gel silica coatings can significantly tailor their refractive indices. Based on the findings, we created broadband antireflection coatings through preparing two-layer coatings. The coatings comprised two layers: a bottom layer with a high refractive index via ammonia treatment of the sol-gel silica coating, and a top layer with a low refractive index from the normal sol-gel coating. The two-layer coatings demonstrated broadband antireflection characteristics, with transmittance higher than 98 % from 350 to 1400 nm. Further hexamethyldisilazane treatment led to formation of hydrophobic coatings, which exhibited high environmental stability. The study demonstrates a new and simple method to create broadband antireflection coatings, and the broadband antireflection coatings could be attractive in many areas, such as solar cells and high-powered laser system.

Silica antireflection coatings from sol-gel processes are of great importance in optical areas because of their capability to reduce light reflection and hence to increase transmission. However, it retained a challenge to enhance the mechanical durability of the sol-gel antireflection coatings. One option is to introduce strong chemical bonding between neighboring silica nanoparticles in the coatings. Here, we demonstrate that ammonia treatment is an effective approach to enhance the mechanical durability of the silica antireflection coatings. The coatings after ammonia treatment exhibited excellent mechanical properties, with tensile hardness of 4.4 GPa, pencil hardness of 4H, and good abrasion resistance, which is noticeably better than the coatings without ammonia treatment. The ammonia treatment did not impair the optical property of the coatings. The coatings after ammonia treatment remained their good transmission, with peak transmittance as high as 99.8%. Mechanism analysis suggests that the enhancement of the mechanical durability is likely due to the condensation of silanol groups between the neighboring silica nanoparticles under ammonia catalysis. The ammonia treatment provides a promising alternative to current approaches for improving the mechanical durability of the sol-gel silica coatings.

Self-cleaning antireflection coatings have potential applications in outdoor conditions and have been the subject of intense study. However, self-cleaning antireflection coatings are commonly prepared via grafting of small hydrophobic molecules, which are susceptible to detachment from the coatings due to hydrolysis, leading to considerable degradation of the self-cleaning functionality in practical applications. Here, we create fluoropolymer brush grafted silica antireflection coatings that demonstrate long-term self-cleaning performance. Fluoropolymer brush grafted silica nanoparticles were synthesized via surface initiated atom transfer radical polymerization and then coated on glass substrates to form antireflection coatings. The brush grafted coatings exhibited excellent transmission, with nearly 100% transmittance at a desired wavelength. The fluoropolymer brushes rendered the coatings hydrophobic, with water contact angle of 122°. Owing to their hydrophobicity, the brush grafted coatings exhibited excellent self-cleaning functionality. A notable advantage of the brush grafted coatings was their stable self-cleaning functionality. The brush grafted coatings remained their hydrophobicity after immersion in acidic solution, with water contact angle being constant at 122°, which were more stable than the small molecule modified hydrophobic coatings. This work opens a new avenue to create highly stable self-cleaning antireflection coatings that will find applications in harsh conditions.

Antireflective coatings with adjustable transmittance and high laser-induced damage threshold (LIDT) have been prepared by the deposition of magnesium fluoride (MgF2) nanoparticles on fused silica substrates. The peak transmittance of the coatings is 99.98%, mainly due to the low refractive index caused by the introduction of porosity between MgF2 nanoparticles. With varying the coating thickness, the optimized antireflective performance of the coatings at any wavelength between 300 and 1100 nm can be achieved. The effect of the particle size on the antireflective properties of the coatings has been also investigated. The coatings prepared from small particles exhibit higher transmittance at short wavelengths than do the coatings prepared from large particles. The LIDTs of the coatings at 351 nm, 527 nm and 1053 nm are 25 J/cm2, 34 J/cm2 and 63 J/cm2, respectively. The high LIDT of the coatings can be mainly attributed to the large band gap of MgF2. The antireflective coatings may be potentially applied in the high-powered lasers.

Antireflection coatings from silica nanoparticles exhibit promising applications in many energy-related areas such as solar-thermal and photo-voltaic systems. However, the coatings suffer from poor mechanical durability and low self-cleaning capability in outdoor conditions, which limit their practical application. Here, we create mechanically robust and self-cleaning antireflection coatings through nanoscale binding of hydrophobic silica nanoparticles with an organosilica binder. The coatings demonstrated nearly full transmission at desired wavelength of ∼550 nm, with peak transmittance up to 99.9%. Further advantage of these coatings is the combination of hydrophobic silica nanoparticles with the organosilica binder, resulting in hydrophobic and mechanically robust coatings, with water contact angle of 161° and hardness of 4.2 GPa. The coatings maintained their high transmittance under outdoor conditions for 3 months, which is largely attributed to their self-cleaning functionality resulting from super-hydrophobicity. We envision that the mechanically robust and self-cleaning antireflection coatings could find wide applications in outdoor conditions and other harsh environments.

Nanostructured magnesium fluoride (MgF 2 ) antireflective films with ultra-high laser induced damage thresholds (LIDTs) have been prepared through dip coating of ~10 nm MgF 2 nanoparticles on fused silica substrates. The films increase transmittance from 93.0% for bare substrates to 99.98% for coated substrates. The LIDTs of the nanostructured MgF 2 films reach as high as 25 J/cm 2 at 351 nm, 34 J/cm 2 at 527 nm and 63 J/cm 2 at 1053 nm, respectively. The LIDTs of the nanostructured MgF 2 films is higher than that of dense MgF 2 films and sol–gel derived silica films. Such high LIDTs of the nanostructured MgF 2 films may be attributed to the large band gap and the quantum size effect of the MgF 2 nanoparticles. These nanostructured MgF 2 films will be utilized as antireflective films used in high-peak-power laser system.

Silica antireflective films modified by polyvinyl butyral (PVB) were deposited on fused silica substrates by sol–gel process. The effects of PVB on the microstructure and laser damage threshold (LIDT) of films were investigated. The results of the nano particle analyzer and scanning probe microscope revealed that PVB molecules surrounded silica particles and controlled the particle growth, which resulted in a stable sol with uniformly distributed silica particles. Therefore, the films deposited from these modified sols possessed more uniform microstructures than the films without PVB. The adhesive-resistance test indicated that the strength of the modified silica films increased due to the bond reaction between PVB molecules and silica particles. The introduction of PVB into silica sols had also increased the LIDT of films. The LIDT of films increased from 30.0 J/cm 2 to 40.1 J/cm 2 after 1.0 wt.% PVB was added. The increase in LIDT was attributed to the increased strength and uniform microstructures of films as an effect of the PVB modification.

Silica antireflective films by the base catalyzed sol–gel process show poor mechanical property. In this study, silica antireflective films with good mechanical property have been prepared by the acid catalyzed templating sol–gel process. The single-layer film was deposited from an acid-catalyzed silica sol solution with polymer F127 incorporation. The silica sol was first dip deposited onto substrate to form films on both sides of the substrate and then subjected to thermal treatment at 500 °C. After thermal treatment, the abrasion resistant antireflective film was achieved due to the formation of porous structure in the resultant film as a result of decomposing F127. Optical spectroscopic measurement shows that the coated glass with maximum transmittance of 99.5% has been obtained. Nanoindenter measurement shows that the elastic modulus and hardness of films are 16 GPa and 1.3, respectively, which are much better than those films derived from base-catalyzed silica sols. The high transmittance and good mechanical property make such films potential in both military and civil applications.

A great deal of intensive research has been conducted to obtain high-quality transparent ultralow-refractive-index and ultralow-dielectric-constant thin films for microptics and microelectronics applications. Here, we report a simple procedure to prepare highly porous silica thin films with high optical quality and water resistance through nano-etching of mesoporous silica films followed by fluoroalkylsilane surface modification. The films possess an ultralow refractive index of 1.03 (800 nm) and an ultralow dielectric constant of 1.30 (100 kHz), to our knowledge the lowest values ever reported in thin film materials. The films are superhydrophobic (water contact angle=156 deg), thus exhibit high moisture stability.