In Situ Transformation of Metal Molybdates into Polymetallic Sulfides with Enriched Edge Sites for High-Performance Supercapacitors.

An effective approach to synthesize polycrystalline Ni-Co-Mo sulfide (NiCoMoS) is developed through doping engineering coupled with chemical transformation. The polycrystalline NiCoMoS with enriched active edge sites is designed and fabricated on a Ni foam (NF) via a facile hydrothermal calcination and post-sulfidation approach, where the polycrystalline NiCoMoO4 precursor is elaborately prepared by doping Co ions into the NiMoO4 lattice and subsequently in-situ-converted into NiCoMoS with 3D architectures of ordered nanoneedle arrays. Benefiting from the unique 3D structure and synergistic effects of each component, the optimized needle-like NiCoMoS(2.0) arraying on a NF as a self-standing electrode exhibits superior electrochemical performances with a high specific charge (920.0 C g-1 at 1.0 A g-1), excellent rate capability, and good long-term stability. Furthermore, the assembled NiCoMoS//activated carbon hybrid device presents a satisfactory supercapacitor performance, affording an energy density of 35.2 W h kg-1 at a power density of 800.0 W kg-1 and competitive long-term stability (83.8% retention at 15 A g-1 after 10,000 cycles). Such a novel strategy may pave a new route for exploring other polymetallic sulfides with enriched, exposed active edge sites for energy-related applications.

Novel hierarchical carbon microspheres@layered double hydroxides@copper lignosulfonate architecture for polypropylene with enhanced flame retardant and mechanical performances.

Due to the inherent defect of flammability of polypropylene (PP), a novel and highly efficient carbon microspheres@layered double hydroxides@copper lignosulfonate (CMSs@LDHs@CLS) flame retardant was designed and prepared, which was attributed to the strong electrostatic interaction between carbon microspheres (CMSs), layered double hydroxides (LDHs) and lignosulfonate as well as the chelation effect of lignosulfonate on copper ions, and then it was incorporated into the PP matrix. Significantly, CMSs@LDHs@CLS not only observably improved its dispersibility in PP matrix, but also simultaneously achieved excellent flame retardant properties for composites. With the addition of 20.0 % CMSs@LDHs@CLS, the limit oxygen index of CMSs@LDHs@CLS and PP composites (PP/CMSs@LDHs@CLS) reached 29.3 % and achieved the UL-94 V-0 rating. Cone calorimeter tests indicated that the peak heat release rate, total heat release and total smoke production of PP/CMSs@LDHs@CLS composites exhibited declines of 28.8 %, 29.2 % and 11.5 %, respectively, compared with those of PP/CMSs@LDHs composites. These advancements were attributed to the better dispersibility of CMSs@LDHs@CLS in PP matrix and illustrated that CMSs@LDHs@CLS observably reduced fire hazards of PP. The flame retardant property of CMSs@LDHs@CLS might relate to condensed phase flame retardant effect of char layer and catalytic charring of copper oxides.

Ni-Co-Mn hydrotalcite-derived hierarchically porous sulfide for hybrid supercapacitors.

Ternary transition metal sulfides have attracted much attention due to their superior electrochemical properties. Nevertheless, it is difficult to commercialize sulfides due to their intrinsic properties such as dull reaction kinetics and an insufficient number of active sites. Herein, a self-supporting porous NiCoMnS sulfide (NiCoMnS/NF) arrayed on nickel foam (NF) with 3D honeycomb-like structure was designed and prepared via a hydrothermal and post-sulfidation process. It was found that the 3D hierarchically network architecture, constructed by nanosheets with abundant cavities, endowed NiCoMnS/NF with a high specific area and rich ion/electron-transport channels, which facilitated ion/electron transfer and Faradaic reaction kinetic. The optimal NiCoMnS/NF exhibited a markedly improved electrochemical performance due to the merits of complementary multi-composition and unique 3D network structure with multi-level "superhighways". Furthermore, the NiCoMnS//AC device fabricated with NiCoMnS/NF cathode and activated carbon (AC) anode delivered an excellent specific charge and exceptional energy density. This work offers a reference for designing the structure of electrode materials.

Tuning oxygen vacancy in Bi2WO6 by heteroatom doping for enhanced photooxidation-reduction properties.

Heteroatom doping was recently regarded as an effective method to tune the band gap and improve the separation and transfer of photogenerated electron-hole pairs in semiconductor photocatalysts. Herein, a novel S,F-codoped Bi2WO6 (S,F-Bi2WO6) with suitable oxygen vacancies was synthesized via the hydrothermal-calcination and post-sulfurization, for efficient Cr(VI) reduction and methyl orange (MO) degradation under visible light. The amount of surface oxygen vacancies could be controlled by adjusting the S/F ratio during the doping process, which modulated the band structure and photogenerated charge behavior of Bi2WO6. The optimal S0.10F-Bi2WO6 exhibited an excellent photooxidation-reduction performance, which Cr(VI) reduction and MO degradation efficiencies were 1.6 and 2.6 times than those of the pristine Bi2WO6 without oxygen vacancy under visible-light, respectively. The enhanced photooxidation-reduction performance was because the right amount of oxygen vacancies could effectively narrow the bandgap and improve the separation efficiency of electron-hole pairs. Thus, this work offered a mild and simply approach for preparing heteroatom doped Bi2WO6 and a potential to be extended to the synthesis of other doped materials for environmental remediation.

Ag-Ag2O decorated multi-walled carbon nanotubes/NiCoAl hydrotalcite sensor for trace nitrite quantification.

Ag-Ag2O-decorated multiwall carbon nanotube/NiCoAl-hydrotalcite (CNT/LDH-Ag) composites were designed and synthesized for nitrite quantification. The materials were characterized by various techniques, and their electrochemical NO2- detection performances investigated using amperometric and differential pulse voltammetry (DPV) techniques. The Ag-Ag2O nanoparticles (NPs) were anchored on the surface of the CNT/LDH-Ag composites. At a suitable amount of the Ag-Ag2O loading, the Ag-Ag2O NPs with small particle size were distributed evenly on the CNT/LDH surface, increasing the surface area of the composites. The optimal CNT/LDH-Ag3 composite exhibited a high electrochemical activity for NO2- oxidation in pH 7.0. Furthermore, the optimal CNT/LDH-Ag3 composite was fabricated for trace NO2- quantification. The proposed sensor displayed a high sensitivity (0.0960 µA·µM-1·cm-2) and fast response (< 3 s) toward NO2- in a wide linear range from 0.250 µmol·L-1 to 4.00 mmol·L-1 with a low detection limit of 0.0590 µmol·L-1(S/N = 3). The sensor provided an outstanding analytical performance with a desirable recovery (95.3 ~ 107%, RSD < 1.05%) in real sample. As a result, the proposed sensor can be used for the real-time quantification of trace NO2- in the biological, food, and environmental fields.

Construction of Ultrafine Ag2S NPs Anchored onto 3D Network Rodlike Bi2SiO5 and Insight into the Photocatalytic Mechanism.

A novel three-dimensional (3D) network rodlike Ag2S/Bi2SiO5 photocatalyst with a p-n heterostructure composed of ultrafine Ag2S nanoparticles (NPs) and Bi2SiO5 nanosheets was prepared using an anionic self-regulation strategy by a two-step hydrothermal process. The architecture facilitated the efficient transfer and separation of photogenerated electron-hole pairs. The optimal Ag2S/Bi2SiO5 composite (ABSO0.10) exhibited an excellent reduction activity (93.5% Cr(VI) removal in wastewater containing 50 mg·L-1 Cr(VI) within 90 min under visible light), which was about 11.2 and 25.6 times higher than that of the pristine Ag2S and virgin Bi2SiO5, respectively. Assisted by experiments and density functional theory (DFT) calculations, a possible photocatalytic mechanism for Cr(VI) reduction over the Ag2S/Bi2SiO5 composite under visible-light irradiation was proposed.

Construction of NiCoZnS materials with controllable morphology for high-performance supercapacitors.

A facile two-step hydrothermal approach with post-sulfurization treatment was put forward to construct the mixed transition metal sulfide (NiCoZnS) with a high electrochemical performance. The different morphologies of NiCoZnS materials were successfully fabricated by adjusted the Ni/Co molar ratio of the NiCoZn(OH)F precursor. Moreover, thein situphase transformation from the NiCoZn(OH)F phase to Zn0.76Co0.24S and NiCo2S4phases and lattice defects via the S2-ion-exchange were determined by x-ray diffractometer, transmission electron microscopy and x-ray photoelectron spectroscopy techniques, which improved electric conductivity and interfacial active sites of the NiCoZnS, and so promoted the reaction kinetics. Significantly, the urchin-like NiCoZnS1/1prepared at the Ni/Co molar ratio of 1.0 exhibited promising electrochemical performances with high capacitance and excellent cycling stability. Furthermore, the asymmetric device (NiCoZnS//AC) using NiCoZnS1/1as the positive electrode had excellent supercapacitor performances with an energy density of 57.8 Wh·kg-1at a power density of 750 W·kg-1as well as a long cycle life (79.2% capacity retention after 10 000 cycles), indicating the potential application in high-performance supercapacitors.

Controllable architecture of the NiCoZnS@NiCoFe layered double hydroxide coral-like structure for high-performance supercapacitors.

The rational design of the morphological structure of electrode materials is considered as an important strategy to obtain high-performance supercapacitors. So, NiCoZnS materials with different Ni/Co/Zn molar ratios on Ni foam (NF) were synthesized, in which the Ni/Co/Zn molar ratio plays a key role in the morphological structure and electrochemical performances. Furthermore, the pre-prepared NiCoZnS materials act as substrates to guide the self-assembling of NiCoFe layered double hydroxide (LDH) nanosheets on the substrate surface to form core-shell electrode materials (NiCoZnS@NiCoFe-LDH) with a 3D mesoporous hierarchical network structure for further improving electrochemical performances. The unique interconnected coral-like NiCoZnS1@NiCoFe-LDH with a large specific surface area (93.1 m2 g-1) and high specific capacitance is achieved at the Ni/Co/Zn molar ratio of 1 : 1 : 1. Benefiting from the unique structural feature and respective merits of the NiCoZnS and NiCoFe-LDH, the NiCoZnS1@NiCoFe-LDH demonstrates an ultrahigh specific capacitance of 1524.0 C g-1 (3386.7 F g-1) at 1.0 A g-1 and excellent 95.0% capacitance retention at 10 A g-1 after 5000 cycles. As for practical application, the assembled NiCoZnS1@NiCoFe-LDH//AC delivers a favorable energy density of 66.25 W h kg-1 at 1500 W kg-1 and a long-term cycling lifetime (86.04% retention at 5.0 A g-1 after 10 000 cycles), which suggests promising potential in energy storage and conversion.

High-sensitive sensor for the simultaneous determination of phenolics based on multi-walled carbon nanotube/NiCoAl hydrotalcite electrode material.

The ternary NiCoAl hydrotalcite (NiCoAl-LDH) was combined with carboxylic multi-walled carbon nanotube (MWCNT) to fabricate a novel electrochemical sensor for simultaneously determining the co-existing trace phenolic substances. The morphology, structure, and electrochemical behavior of the as-prepared materials were characterized by various techniques. Benefitting from the great conductivity of MWCNT and high electrocatalytic activity of NiCoAl-LDH for phenolic substances, the advanced MWCNT/NiCoAl-LDH sensor presented a fast response, high sensitivity, excellent stability, and satisfactory replicability. The sensor offered good linear responses in the ranges1.50~600 µM to hydroquinone (HQ), 5.00~1.03 × 103 µM to catechol (CC), and 6.00 × 10-2~250 µM to bisphenol A (BPA). The detection limits of HQ, CC, and BPA were 0.4, 0.8, and 6. × 10-3 µM (S/N = 3), respectively. In environmental water, the sensor achieved satisfactory recoveries for the simultaneous detection of HQ (98.6~101%), CC (98.0~101%), and BPA (97.5~101%), with relative standard deviations less than 4.4%.

[Study on the Analytical Method of Solid Phase Extraction-Ultra Performance Liquid Chromatography Tandem Quadrupole Linear Ion Trap Mass Spectrometry for 12 Perfluorinated Compounds in Human Urine].

OBJECTIVE: To establish a method for simultaneous determination of 12 kinds of perfluorinated compounds (PFCs) in human urine based on ultra performance liquid chromatography tandem quadrupole linear ion trap mass spectrometry (UPLC-QTtrap-MS). METHODS: After pH adjustment with 2% formic acid, the urine samples were loaded on a WAX solid phase extraction (SPE) cartridge for extraction, purification and concentration. The eluates were collected, concentrated to dryness under nitrogen, and reconstituted with 10 mmol/L ammonium acetate aqueous solution-methanol ( V water∶ V methanol = 70∶30) before injection. UPLC was performed on a C 18 cartridge, and methanol and 10 mmol/L ammonium acetate aqueous solution was used as mobile phases with gradient elution. QTtrap-MS was operated in multiple reaction monitoring (MRM) mode, and the internal standard calibration curves were applied for quantitative analysis. RESULTS: Good linearity was obtained in the linear range, with the method detection limits and method quantification limits being 0.032 ng/L-6.5 ng/L and 0.10 ng/L-21 ng/L, respectively, for the 12 kinds of PFCs. The spiked recoveries of the 12 kinds of PFCs were 91.5%-114%, with the intra-day precision and the inter-day precision being 0.57%-16.0% and 1.88%-20.1%, respectively. The established method was applied to the determination of 12 kinds of PFCs in the urine samples of primary school students collected in one area. Nine kinds of PFCs were detected in the urine samples in this area. Among the PFCs detected, perfluorobutanesulfonic acid (PFBS) and perfluorooctanoic acid (PFOA) were the main PFCs found in the student urine samples. CONCLUSION: The method established in this study could be used to simultaneously examine 12 kinds of PFCs in urine. The method combined SPE with isotope internal standard correction and achieved good sensitivity and accuracy.

Renewable lignin-based surfactant modified layered double hydroxide and its application in polypropylene as flame retardant and smoke suppression.

A novel and environmentally friendly lignin-based surfactant sodium lignosulfonate (SLS) modified layered double hydroxide (LDH) flame retardant (LDH-LS) was fabricated via co-precipitation method, and subsequently incorporated into polypropylene (PP) matrix to obtain the PP and LDH-LS composites (PP/LDH-LS) by melt blending method. The XRD, FT-IR and XPS results indicated that SLS had successfully modified LDH by adsorbing on the surface of the LDH nanosheet. The WCA and SEM results revealed that the hydrophobic property of LDH-LS had been evidently improved, and it displayed a more homogeneous dispersion than virgin LDH in the PP matrix. Furthermore, cone calorimetry tests (CCT) illustrated that the peak heat release rate (PHRR), total heat release (THR), and total smoke release (TSR) of PP/LDH-LS composites exhibited declines of 62.9%, 25.1%, and 43.3% compared with those of Neat PP, respectively. Besides, the PP/LDH-LS achieved a LOI value of 29.4% and a UL-94 V-0 rating, whereas the PP/LDH showed only a LOI value of 25.2% and a UL-94 V-2 rating at 20 wt% loading. These improvements of flame retardant properties can be attributed to that the well-dispersed LDH-LS and synergistic flame retardancy between LDH and SLS.

Adsorption Behaviour of Cr(VI) from Ternary Mesoporous Mg/Fe/Al Oxide Using Glucose as a Soft Template.

The ternary mesoporous MgFeAl oxide (MgFeAlO) material was designed and prepared using glucose as a soft template by calcination of its MgFeAl hydrotalcite precursor. The MgFeAlO showed significantly better Cr(VI) adsorption performance than binary MgAlO. The effect of Fe3+ on Cr(VI) removal in simulated wastewater was studied by researching the microstructure, adsorption properties and mechanism of the material. The results showed that the addition of Fe3+ affected the microstructure of MgAlO, where the partial substitution of Al3+ by Fe3+ into the host layers resulted in an increase in the interlayer region and specific area (SBET) as well as an enlargement in mesoporous feature into the MgFeAlO. The Cr(VI) adsorption process, taking place by the reconstruction of the MgFeAlO oxide with water (memory effect) companying with the intercalation of CrO2-4 anions, was much more efficient than that occurring in the binary MgAlO. MgFeAlO's adsorption of Cr(VI) follows the pseudo-second-order model and it is controlled by intra particle diffusion. The adsorption isotherm was better fitted by the Langmuir model, suggesting that the Cr(VI) adsorption was a monolayer adsorption onto the homogeneous support surface. All thermodynamic and kinetic calculations suggested that the Cr(VI) adsorption process on the MgFeAlO was of chemisorption nature, in which activation energy (Ea) and enthalpy change (ΔH) were 30.01 and 193.58 kJ·mol-1, respectively.

Fabrication of green alginate-based and layered double hydroxides flame retardant for enhancing the fire retardancy properties of polypropylene.

An efficient and bio-based alginate pillared hydrotalcite (SA@LDHs) was fabricated via calcination-reconstruction manner with sodium alginate (SA) and hydrotalcite (LDHs-C), and used as novel flame retardant for polypropylene (PP). The morphologies and combustion properties of SA@LDHs and its hybrid with PP composites (PP/SA@LDHs) had been characterized by SEM, TGA, cone calorimetry, LOI and UL-94 measurements. With 30 wt% loading, the SA@LDHs achieved a LOI value of 30.9 % and a UL-94 V-0 rating, whereas the LDHs-C exhibited only LOI value of 27.6 % and a UL-94 V-1 rating. The peak heat release rate, total heat release and total smoke production of PP/SA@LDHs were 260.8 kW m-2, 61.3 MJ m-2 and 8.2 m2, respectively, which presented declines of 69.2 %, 42.8 % and 32.2 % compared with those of Neat PP. These improvements could be attributed to the presence of the radical-trapping effect of SA, which leading to promote PP chains to participate in the carbonization process.

Enhanced efficiency in isolation and expansion of hAMSCs via dual enzyme digestion and micro-carrier.

A two-stage method of obtaining viable human amniotic stem cells (hAMSCs) in large-scale is described. First, human amniotic stem cells are isolated via dual enzyme (collagenase II and DNAase I) digestion. Next, relying on a culture of the cells from porous chitosan-based microspheres in vitro, high purity hAMSCs are obtained in large-scale. Dual enzymatic (collagenase II and DNase I) digestion provides a primary cell culture and first subculture with a lower contamination rate, higher purity and a larger number of isolated cells. The obtained hAMSCs were seeded onto chitosan microspheres (CM), gelatin-chitosan microspheres (GCM) and collagen-chitosan microspheres (CCM) to produce large numbers of hAMSCs for clinical trials. Growth activity measurement and differentiation essays of hAMSCs were realized. Within 2 weeks of culturing, GCMs achieved over 1.28 ± 0.06 × 107 hAMSCs whereas CCMs and CMs achieved 7.86 ± 0.11 × 106 and 1.98 ± 0.86 × 106 respectively within this time. In conclusion, hAMSCs showed excellent attachment and viability on GCM-chitosan microspheres, matching the hAMSCs' normal culture medium. Therefore, dual enzyme (collagenase II and DNAase I) digestion may be a more useful isolation process and culture of hAMSCs on porous GCM in vitro as an ideal environment for the large-scale expansion of highly functional hAMSCs for eventual use in stem cell-based therapy.

Preparation of a NiAl-Oxide@Polypyrrole Composite for High-Performance Supercapacitors.

A core-shell NiAlO@polypyrrole composite (NiAlO@PPy) with a 3D "sand rose"-like morphology was prepared via a facile in situ oxidative polymerization of pyrrole monomer, where the role of PPy coating thickness was investigated for high-performance supercapacitors. Microstructure analyses indicated that the PPy was successfully coated onto the NiAlO surface to form a core-shell structure. The NiAlO@PPy exhibited a better electrochemical performance than pure NiAlO, and the moderate thickness of the PPy shell layer was beneficial for expediting the electron transfer in the redox reaction. It was found that the NiAlO@PPy5 prepared at 5.0 mL L-1 addition amount of pyrrole monomer demonstrated the best electrochemical performance with a high specific capacitance of 883.2 F g-1 at a current density of 1 A g-1 and excellent capacitance retention of 91.82 % of its initial capacitance after 1000 cycles at 3 A g-1 . The outstanding electrochemical performance of NiAlO@PPy5 were due to the synergistic effect of NiAlO and PPy, where the uniform network-like PPy shell with the optimal thickness made electrolyte ions more easily accessible for faradic reactions. This work provided a simple approach for designing organic-inorganic core-shell materials as high-performance electrode materials for electrochemical supercapacitors.

Optimization of ZnAl/Chitosan Supra-Nano Hybrid Preparation as Efficient Antibacterial Material.

The menace of antimicrobial resistance continues to increase and hence the need to discover new antibiotics, especially alternative and effective sources such as hybrid organic-inorganic, organic-organic materials, and other combinations. In this study, an antimicrobial hybrid supra-nano material was prepared by the bi-titration synthesis method of chitosan (CS) and ZnAl layered double hydroxide. Fourier-transform infrared spectrometer (FTIR), thermogravimetric and differential thermal gravimetric (TGA/DTG), ultraviolet-visible (UV-Vis), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses indicated that the ZnAl/CS hybrid exhibited low crystallinity with high thermal stability. The results of ZnAl/CS characterization showed the characteristic properties of the individual components ZnAl and CS, indicating a successful preparation of the ZnAl/CS hybrid. The antibacterial tests revealed that the ZnAl/CS hybrid possessed an enhanced antimicrobial effect against both Escherichia coli (E. coli, MTCC 739) and Penicilliumcyclopium (P. cyclopium, AS 3.4513). Under the central composite design (CCD) of the response surface methodology (RSM) tool, the parameters of the hybrid synthesis reaction were optimized and the result obtained was as follows: reaction pH was 11.3, reagent Zn/Al ratio was 3.27, and chitosan concentration was 1.07 g/L. After optimization, it was found that the antibacterial activity of ZnAl/CS was strengthened against E. coli as evidenced by a widening of the inhibition zone of about 41.6%. The antibacterial activity of ZnAl/CS was mainly due to the reactivation of the antibacterial activity of CS associated with the release of Zn2+ and Al3+ metal ions in addition to ZnO, Al2O3, and ZnAl2O4 compounds resulting from the method of preparation.

Preparation of the Hybrids of Hydrotalcites and Chitosan by Urea Method and Their Antimicrobial Activities.

Hybrid nano-supra molecular structured materials can boost the functionalityof nano- or supra-molecular materials by providing increased reactivity and conductivity, or by simply improving theirmechanical stability. Herein, the studies in materials science exploring hybrid systems are investigated from the perspective of two important related applications: healthcare andfood safety.Interfacing phase strategy was applied, and ZnAl layered double hydroxide-chitosan hybrids, prepared by the urea method (U-LDH/CS), were successfully synthesized under the conditions of different chitosan(CS) concentrations with a Zn/Al molar ratio of 5.0. The structure and surface properties of the U-LDH/CS hybrids were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectrometer(FTIR), scanningelectronmicroscopy(SEM), ultravioletvisible(UV-Vis), and zero point charge (ZPC) techniques, where the effect of CS concentration on the structure and surface properties was investigated. The use of the U-LDH/CS hybrids as antimicrobial agents against Escherichia coli, Staphylococcus aureus,and Penicilliumcyclopiumwasinvestigated in order to clarify the relationship between microstructure and antimicrobial ability. The hybrid prepared in a CS concentration of 1.0 g∙L-1 (U-LDH/CS1) exhibited the best antimicrobial activity and exhibited average inhibition zones of 24.2, 30.4, and 22.3mm against Escherichia coli, Staphylococcus aureus, and Penicilliumcyclopium, respectively. The results showed that the appropriate addition of CS molecules could increase antimicrobial ability against microorganisms.

Microwave Pretreatment and Enzymolysis Optimization of the Lotus Seed Protein.

Pretreatment with a microwave was conducted before enzymolysis and shown to enhance the enzymolysis, which changed the secondary structure of the lotus seed protein. Under high-power microwave irradiation, sub bonds of the protein were broken, causing disaggregation and unfolding of the secondary structure, namely a decrease in the intermolecular aggregate structure and increase in the random coil structure, making the protein bonds susceptible to papain in the enzymolysis. On the other hand, a response surface methodology (RSM) was launched to investigate the influence of the enzymolysis process variables on the DH (degree of hydrolysis). The statistical analysis revealed that the optimized conditions were a protein substrate concentration of 15 g/L, pH of 5.5, enzymolysis temperature of 57 °C, papain amount of 0.5 g/L, and enzymolysis time of 45 min, for which the predicted value of the DH was 35.64%. The results indicated that a microwave also had better potential for applications in the enzymolysis of foods.

Fabrication of Ag2O/Ag decorated ZnAl-layered double hydroxide with enhanced visible light photocatalytic activity for tetracycline degradation.

The photocatalytic performance of layered double hydroxides (LDH) is usually confined to the slow interface mobility and high recombination rate of photogenerated electron-hole pairs in material. To overcome the low photocatalytic efficiency, novel Ag2O/Ag decorated LDH (LDH-Ag2O/Ag) was successfully synthesized by depositing Ag2O on the surface of LDH and then converted to Ag° nanoparticles in the right position after heat treatment. The as-synthesized LDH-Ag2O/Ag composites were characterized by Powder X-ray diffraction (XRD), Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectra (UV-vis DRS), photoluminescence spectra (PL) and transient photocurrent (TPC) analysis. Compared with virgin LDH, the photocatalytic activities of LDH-Ag2O/Ag composites were enhanced significantly. The optimum photocatalytic efficiency of LDH-Ag10 (0.0184 min-1) was nearly 46 times higher than that of virgin LDH (0.0004 min-1). The result of active species trapping experiments indicated that •OH, h+, and •O2- have an effect on the TC degradation, where •OH played the predominant role during the photocatalytic process. The possible photocatalytic mechanisms involving the charge transfer pathway and reactive species generation during the process of TC degradation were also discussed. The improved photocatalytic activity of LDH-Ag2O/Ag could be attributed to the synergetic effect between LDH and Ag2O/Ag that extended visible light range and reduced photogenerated charge carriers recombination.

An Advanced NiCoFeO/Polyaniline Composite for High-Performance Supercapacitors.

To reduce the charge-transfer resistance of supercapacitors and achieve faster reversible redox reactions, ternary Ni-Co-Fe layered double hydroxide was prepared by using the urea method and then calcined to give NiCoFe oxide (NiCoFeO). To enhance conductivity, a polyaniline (PANI) conductive layer was assembled on the surface of the NiCoFeO particles by in situ oxidative polymerization of aniline monomers. The as-prepared NiCoFeO/PANI composite was successful employed as a supercapacitor electrode. It was found that the NiCoFeO/PANI composite displayed good cycling stability, with a capacity loss of only 29.54 % after 5000 cycles. Furthermore, the NiCoFeO/PANI composite also exhibited excellent supercapacitor performance, with a high specific capacity of 843 F g-1 at a current density of 2 A g-1 , whereas NiCoFeO showed a specific capacity of only 478 F g-1 . This result was attributed to the synergistic effect between NiCoFeO and PANI. The facile synthesis strategy and excellent electrochemical performance suggest that NiCoFeO/PANI is a promising economical electrode material for applications in supercapacitors.