Zhanshuang Li

Optimizing the charge transfer process by designing Co3O4@PPy@MnO2 ternary core–shell composite

In this paper, the incorporation of a highly conductive material (polypyrrole) into a binary metal-oxide core–shell structured composite is adopted to optimize the charge transfer process to further improve electrochemical performance. Because of enhanced electron transfer capability, charge transfer resistances of the ternary core–shell structured composites are reduced and the electrochemical performances are improved. For example, the Co3O4@PPy@MnO2 ternary core–shell heterostructured composite exhibits high specific capacitance and excellent rate capability (53% of capacity retention rate at 40 A g−1 compared with 782 F g−1 at 0.5 A g−1). The composite shows good cycling stability with 97.6% capacity retention over 2000 cycles at 5 A g−1. These results demonstrate the potential of core–shell composites to further improve the performance in supercapacitor electrodes.

A graphene oxide/amidoxime hydrogel for enhanced uranium capture.

The efficient development of selective materials for the recovery of uranium from nuclear waste and seawater is necessary for their potential application in nuclear fuel and the mitigation of nuclear pollution. In this work, a graphene oxide/amidoxime hydrogel (AGH) exhibits a promising adsorption performance for uranium from various aqueous solutions, including simulated seawater. We show high adsorption capacities (Qm = 398.4 mg g−1) and high % removals at ppm or ppb levels in aqueous solutions for uranium species. In the presence of high concentrations of competitive ions such as Mg2+, Ca2+, Ba2+ and Sr2+, AGH displays an enhanced selectivity for uranium. For low uranium concentrations in simulated seawater, AGH binds uranium efficiently and selectively. The results presented here reveal that the AGH is a potential adsorbent for remediating nuclear industrial effluent and adsorbing uranium from seawater.

Synthesis of alumina nanosheets via supercritical fluid technology with high uranyl adsorptive capacity

Supercritical carbon dioxide is beneficial to the synthesis of superior ultrafine and uniform materials due to its high chemical stability, low viscosity, high diffusivity, and “zero” surface tension. γ-Alumina nanosheets were obtained by a simple hydrothermal route in the presence of supercritical carbon dioxide. XRD, FTIR, SEM, TEM and nitrogen sorption isotherm were employed to characterize the samples. Alumina as-prepared has a high specific surface area of up to 200 ± 6 m2 g−1, which presents a high adsorption capacity (4.66 ± 0.02 mg g−1) for uranyl ions from aqueous solution. Furthermore, the adsorption process was found to be endothermic and spontaneous in nature.

Magnetic, Luminescent Eu‐Doped Mg–Al Layered Double Hydroxide and Its Intercalation for Ibuprofen

A magnetic, luminescent Eu-doped Mg-Al layered double hydroxide with ibuprofen (IBU) intercalated in the gallery has been successfully prepared by a simple coprecipitation method. The physicochemical properties of the samples were well characterized by powder XRD, TEM, FTIR, TGA, inductively coupled plasma MS (ICP-MS), vibrating sample magnetometry (VSM), and fluorospectrophotometry. The results revealed that Fe(3)O(4) nanoparticles are coated on the surface of layered double hydroxides and the obtained (Mg(2)Al(0.95)Eu(0.05))(Fe)-(IBU) sample exhibits both superparamagnetic and luminescent properties, with a saturation magnetization value of 1.86 emu  g(-1) and a strong emission band at 610 nm, respectively. Additionally, it was found that the ibuprofen loading amount is about 31 % (w/w), and the intercalated ibuprofen possesses sustained release behavior when the magnetic, luminescent composite is immersed in simulated body fluid (SBF).

Deft dipping combined with electrochemical reduction to obtain 3D electrochemical reduction graphene oxide and its applications in supercapacitors

In this paper, a combination of deft dipping and simple rapid electrochemical reduction were used to coat electrochemically reduced graphene oxide (ERGO) on Ni foam. After acid etching, a 3D ERGO with sufficient mechanical strength, low density and high electrical conductivity was obtained. As proof, a high mass loading of Co3O4 sheets has been grown on the 3D ERGO. The 3D ERGO/Co3O4 composite electrode exhibits a specific capacitance of 600 F g−1 and a power density of 2.5 kW kg−1.

Facile synthesis of magnetic carboxymethylcellulose nanocarriers for pH-responsive delivery of doxorubicin

The design of a single nanosystem with multifunctional surface properties via selecting the appropriate materials and synthesis methods was shown to be crucial for the development of drug delivery systems. In this work, modified magnetic nanocarriers have been successfully constructed using carboxymethylcellulose as the stabilization agents through a facile one-step hydrothermal method. The modified magnetic nanocarriers exhibited a high magnetic saturation of 54.6 emu g−1 and excellent biocompatibility which was detected by a standard MTT cell assay with L929 cell lines; the nanomaterials proved reusable for drug delivery. Subsequently, doxorubicin (DOX) was loaded onto the surface of the nanocarriers and a high loading efficiency of 92.5% was attained. The results from the release characteristics of the DOX-loaded nanocarriers demonstrated that these modified magnetic nanocarriers were highly stable at neutral pH (blood plasma) and strongly pH-responsive for drug delivery in an acidic environment (tumor tissue). The as-prepared multi-functional nanocarriers showed promising potential as drug carriers to improve the therapeutic efficacy of drugs.

Preparation and Characteraction of New Magnetic Co–Al HTLc/Fe3O4Solid Base

Novel magnetic hydrotalcite-like compounds (HTLcs) were synthesized through introducing magnetic substrates (Fe3O4) into the Co–Al HTLcs materials by hydrothermal method. The magnetic Co–Al HTLcs with different Fe3O4contents were characterized in detail by XRD, FT-IR, SEM, TEM, DSC, and VSM techniques. It has been found that the magnetic substrates were incorporated with HTLcs successfully, although the addition of Fe3O4might hinder the growth rate of the crystal nucleus. The morphology of the samples showed the relatively uniform hexagonal platelet-like sheets. The grain boundaries were well defined with narrow size distribution. Moreover, the Co–Al HTLcs doped with magnetic substrates presented the paramagnetic property.

Hierarchically structured layered-double-hydroxides derived by ZIF-67 for uranium recovery from simulated seawater

Under the background of increasing and sustainable development of nuclear industry, it is significant to develop materials with high adsorption capacity and high selectivity of uranium as adsorbents. In this work, novel Mg-Co layered-double-hydroxide (LDH) with hierarchical structure was synthesized successfully via self-sacrifice template by ZIF-67. X-ray diffraction (XRD) technique, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller surface area measurement (BET) and X-ray photoelectron spectroscopy (XPS) characterization were conducted, which confirmed the specifically hollow structured material possesses high surface area and abundant mesopores that makes uranium ions diffuse into it more easily. In typical batch adsorption experiments, varieties of parameters were investigated in details. In addition, adsorption of trace concentration of uranium (ppb level) in simulated seawater was also studied. The results showed as-prepared Mg-Co LDHs are promising adsorbents for extraction of uranium from simulated seawater.

Single-step synthesis of layered double hydroxides ultrathin nanosheets

A novel single-step approach was developed to prepare large-scale MgAl-LDHs ultrathin nanosheets. The key point of the successful realization was that we employed a high concentration of H(2)O(2). Oxygen molecules, derived from in situ decomposition of H(2)O(2), were speculated to be the decisive factor leading to complete separation of LDHs layers. The ultrathin nanosheets were characterized by XRD, TEM, AFM, FT-IR, and TG-DSC. The results indicated that the thickness of these nanosheets was about 1.44 nm, which was almost in perfect agreement with the theoretical thickness of two LDHs layers. From the TG-DSC curves, the weight loss of these exfoliated MgAl-LDHs ultrathin nanosheets at 500°C was 18.5%, which was much smaller compared to the 32.3% weight loss of unexfoliated MgAl-LDHs.

Interfacial growth of a metal–organic framework (UiO-66) on functionalized graphene oxide (GO) as a suitable seawater adsorbent for extraction of uranium(VI)

Extraction of radioactive uranium (U(VI)) from seawater has recently received extensive attention in the nuclear energy field. In this study, to acquire more void space of an MOF as active points for improving adsorption capacity, GO–COOH/UiO-66 composites were designed via coordination of the carboxyl groups of GO with zirconium ion of UiO-66; this was included as a part of the rapid and effective two-step method. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to determine the effectiveness of the synthesis of GO–COOH/UiO-66 composites. The GO–COOH/UiO-66 composites were investigated for adsorption of U(VI) from an aqueous solution and artificial seawater. The results showed that the GO–COOH/UiO-66 composites had a high adsorption capacity at a suitable seawater pH with a high removal rate of U(VI) at the ppb and ppm levels. The adsorption process closely fitted the Langmuir isotherm model and pseudo-second-order rate equation. Based on the FTIR spectroscopy, the change in pH before and after the adsorption of U(VI), and X-ray photoelectron spectroscopy (XPS), a possible sorption mechanism of U(VI) onto GO–COOH/UiO-66 composites was revealed. In addition, the adsorbent showed good chemical stability under the operating conditions for the adsorption–desorption of U(VI) from an aqueous solution, which indicated a promising potential for applications in the extraction of U(VI) in seawater.