Latest ArticlesThe first-principles calculations demonstrate that covalently bonded (cb) heterojunction and van der Waals (vdW) heterojunction can coexist in silicene/CeO2 heterojunctions, due to the different stacking patterns. Especially, the cb heterojunction with band gap of 1.97 eV, forms a type-II heterojunction, exhibits good redox performance and has high-effective optical absorption spectra, thus it is a promising photocatalyst for overall water splitting. Besides, for the vdW heterojunction, the Dirac cone of silicene is well kept on CeO2 semiconducting substrate, with a considerable energy gap of 0.43 eV, which can be an ideal material in building silicene-based electronic device. These results may open a new gateway in both of nanoelectronic device and energy conversion for silicene/CeO2 nanocomposites.
Iron fluoride (FeF3) is considered as a promising cathode material for Li-ion batteries (LIBs) due to its high theoretical capacity (712 mAh/g) with a 3e− transfer. Herein, we have designed a strategy of hierarchical and mesoporous FeF3/rGO hybrids for LIBs, where the hollow FeF3 nanospheres are the main contributor to the specific capacity and the 2D rGO nanosheets are the matrix elevating the electronic conductivity and buffering the volume expansion. The unique FeF3/rGO hybrid can be rationally synthesized by a non-aqueous in-situ precipitation method, offering the merits of large specific surface area with rich active sites, fast transport channels for lithium ions, effective alleviation of volume expansion during cycles, and accelerating the electrochemical reaction kinetics. The FeF3/rGO hybrid electrode possesses a high initial discharge capacity of 553.9 mAh/g at a rate of 0.5 C with 378 mAh/g after 100 cycles, acceptable rate capability with 168 mAh/g at 2 C, and feasible high-temperature operation (320 mAh/g at 70 ℃). The superior electrochemical behaviors presented here demonstrates that the FeF3/rGO hybrid is a potential electrode for LIBs, which may open up a new vision to design high-efficiency energy-storage devices such as LIBs based on transition metal fluorides.
Water pollution has become a serious problem owing to the development of society. Photocatalysis is a promising approach to remove various pollutants in water, such as organic pollutants and antibiotic resistance bacteria. Meanwhile, the design of heterojunction between two semiconductors is an effective path to improve photocatalytic properties due to its potential in improving separation and transfer of photoinduced carriers. In this study, Nb2O5/g-C3N4 (NO/CN) composite materials were prepared through a one-step heating method. Characterizations confirmed successful preparation of NO/CN heterojunction structure and better optical properties than pure g-C3N4 and Nb2O5. NO/CN composite materials showed excellent photocatalytic efficiency for Escherichia coli (E. coli) inactivation (95%) compared with the pure Nb2O5 (10%) and g-C3N4 (77%). Meanwhile, NO/CN exhibited better organic pollutants removal (RhB for 94%, methyl orange (MO) for 15% and methylene blue (MB) for 87%) under visible light, which is likely owing to the heterojunction structure between g-C3N4 and Nb2O5 that leads to the good separation of photogenerated electron-hole pair. Free radical scavenging and electron spin resonance (ESR) experiments demonstrated that superoxide radicals (•O2−) and holes (h+) were the dominant radicals. Therefore, the NO/CN was proposed to be a promising material for effective disinfection and removal of organic contaminants in water treatment.
Photocatalytic optical fibers are promising for the degradation of gaseous and volatile pollutants in air due to their high specific surface area, high light utilization efficiency, easy regeneration, and sustainability. In particular, photocatalytic optical fibers have proven highly useful for the removal and conversion of different kinds of air pollutants in air. However, these fibers suffer from low photocatalytic degradation efficiencies. In this review, we have focused on introducing photocatalytic quartz optical fibers and photocatalytic plastic optical fibers for the degradation and transformation of gas-phase air pollutants. The principle of photocatalytic optical fibers and main methods for improving their photocatalytic and light utilization efficiencies based on semiconductor photocatalytic coatings are summarized. Moreover, the Langmuir-Hinshelwood kinetic rate equation was summarized to analyze the photocatalytic reduction of gaseous pollutants. Finally, an outlook on the future of photocatalytic optical fibers toward the removal and conversion of gaseous air pollutants is discussed.
The development of effective uranium-removal techniques is of great significance to the environment and human health. In this work, a double potential step technique (DPST) was applied to remove U(VI) from uranium-containing wastewater using a carbon felt electrode modified by graphene oxide/phytic acid composite (GO-PA@CF). The application of DPST can inhibit water splitting and prevent GO-PA from adsorbing other interfering ions in wastewater. The GO-PA composite can effectively accelerate the electrochemical reduction rate of U(VI), which significantly improved the electrochemical deposition rate of uranium oxide. As a result, the maximum removal efficiency and maximum removal capacity of GO-PA@CF electrode reached 98.7% and 1149.3 mg/g, respectively. The removal efficiency remained 97.2% after five cycles of reuse. Moreover, the removal efficiency of GO-PA@CF electrode can reach more than 70% in simulated wastewater.
As an important anode material for fast-charging Li-ion batteries (LIBs), black phosphorus (BP) has attracted extensive attention. Black phosphorene nanotubes (BPNTs) can be theoretically produced by rolling up the black phosphorene nanosheet along armchair (a-BPNTs) and zigzag (z-BPNTs) directions. The effects of curvature, chirality, Li-storage concentrations and strain stress on the Li-storage performance such as Li diffusion barriers and mechanical stabilities of BPNTs are mainly investigated by first principles calculations. The theoretical calculations predict that the a-BPNTs and z-BPNTs have good maximum Li-storage capacities, and the z-BPNTs exhibit better flexibility than a-BPNTs. The mechanical stabilities and Li-migration are all related to the curvature of BPNTs. Additionally, both a-BPNTs and z-BPNTs exhibit fast Li-ion conductivity along the c-axis direction. Moreover, the average Poisson's ratio of a-BPNTs (0.68) is larger than that of z-BPNTs (0.17), indicating that the strain stress is more difficult to apply on a-BPNTs than z-BPNTs. Our calculations predict that the a-BPNTs can afford ultrafast kinetic rate for fast-charging and high-power LIBs, while the z-BPNTs can provide extra capacity for high-energy LIBs.
Amphiphilic molecules adsorbed at the interface could control the orientation of liquid crystals (LCs) while LCs in turn could influence the distributions of amphiphilic molecules. The studies on the interactions between liquid crystals and amphiphilic molecules at the interface are important for the development of molecular sensors. In this paper, we demonstrate that the development of smectic LC ordering from isotropic at the LC/water interface could induce local high-density distributions of amphiphilic phospholipids. Mixtures of liquid crystals and phospholipids in chloroform are first emulsified in water. By fluorescently labeling the phospholipids adsorbed at the interface, their distributions are visualized under fluorescent confocal microscope. Interestingly, local high-density distributions of phospholipids showing a high fluorescent intensity are observed on the surface of LC droplets. Investigations on the correlation between phospholipid density, surface tension and smectic LC ordering suggest that when domains of smectic LC layers nucleate and grow from isotropic at the LC/water interface as chloroform slowly evaporates at room temperature, phospholipids transition from liquid-expanded to liquid-condensed phases in response to the smectic ordering, which induces a higher surface tension at the interface. The results will provide an important insight into the interactions between liquid crystals and amphiphilic molecules at the interface.
Quantitative information, such as environmental migration, absorption, biodistribution, biotransformation, and elimination, is fundamental and essential for the nanosafety evaluations of nanomaterials. Due to the complexity of biological and environmental systems, it is challenging to develop quantitative approaches and tools that could characterize intrinsic behaviors of nanomaterials in the organisms. The isotopic tracers are ideal candidates to tune the physical properties of nanomaterials while preserving their chemical properties. In this review article, we summarized the stable isotope labeling methods of nanomaterials for evaluating their environmental and biological effects. The skeleton labeling protocols of carbon nanomaterials and metal/metal oxide nanoparticles were introduced. The advantages and disadvantages of stable isotope labeling were discussed in comparison with other quantitative methods for nanomaterials. The quantitative information of nanomaterials in environmental and biological systems was summarized along with the biosafety data. The benefits for drug development of nanomedicine were analyzed based on the targeting effects, persistent accumulation, and safety. Finally, the challenges and future perspectives of stable isotope labeling in nanoscience and nanotechnology were discussed.
In this work, we proposed a new U(Ⅵ) removal strategy combining adsorption and photocatalytic reduction by the PMo12/UiO-66 heterojunctions. The PMo12 has been encapsulated in the cavities of UiO-66 by a one-step hydrothermal method, and the PMo12/UiO-66 exhibited high adsorption capacity and photocatalytic activity. The maximal theoretical sorption capacity of U(Ⅵ) on 15% PMo12/UiO-66 reached 225.36 mg/g and the photoreduction rate of 15% PMo12/UiO-66 is about thirty times as much as UiO-66. Under the light irradiation, the photogenerated electrons rapidly transport from UiO-66 to PMo12, and the photo-generated electrons could efficiently reduce the pre-enriched U(Ⅵ) to U(Ⅳ). This work provides new insights into remediation of the radioactive environment.
As one of the most common cancers in the world, hepatocellular carcinoma (HCC) has become a major threat to human health. Radioembolization is a first-line option for the treatment of HCC, especially when other conventional treatments fail or there exist some relative contraindications. Herein, we developed a facile and efficient method for preparing 177Lu-microspheres potentially useful for precise radioembolization therapy of HCC. The radiolabeling efficiency of 177Lu-microspheres was as high as 96.8% ± 0.5%, and the radiolabeling process did not alter the morphology of the mother microspheres. The SPECT/CT studies enabled by the unique emissions of 177Lu suggested that almost no 177Lu ion loaded by the microspheres was released over more than 32 d in vivo, which led to remarkable inhibition effect on the growth of HepG2 tumors subcutaneously transplanted in mice. The current approach may thus offer promising 177Lu-microspheres for clinical radioembolization of HCC.