ZnS/graphene nanocomposites with different graphene concentrations （5, 10 and 15 wt.%） were synthesized using L-cysteine as surfactant and graphene oxide （GO） powders as graphene source. Excellent performance for ...ZnS/graphene nanocomposites with different graphene concentrations （5, 10 and 15 wt.%） were synthesized using L-cysteine as surfactant and graphene oxide （GO） powders as graphene source. Excellent performance for nanocomposites to remove methylene blue （MB） dye and hexavalent chromium （Cr（VI）） under visible-light illumina- tion was revealed. TEM images showed that ZnS NPs were decorated on GO sheets and the GO caused a significant decrease in the ZnS diameter size. XRD patterns, XPS and FTIR spectroscopy results indicated that GO sheets changed into reduced graphene oxide （rGO） during the synthesis process. Photocurrent measurements under a visible- light source indicated a good chemical reaction between ZnS NPs and rGO sheets.展开更多
In order to achieve effective, economic, and easily achievable photocatalyst for the degradation of dye methyl orange（MeO）, ZnO, ZnO/ZnS and ZnO/ZnS/α-Fe2O3 nanocomposites were prepared by simple chemical synthetic...In order to achieve effective, economic, and easily achievable photocatalyst for the degradation of dye methyl orange（MeO）, ZnO, ZnO/ZnS and ZnO/ZnS/α-Fe2O3 nanocomposites were prepared by simple chemical synthetic route in the aqueous medium. Phase, crystallinity, surface structure and surface behavior of the synthesized materials were determined by X-ray diffraction（XRD） and Brunauer-Emmett-Teller analysis（BET） techniques. XRD study established formation of good crystalline ZnO, ZnO/ZnS and ZnO/ZnS/α-Fe2O3 nanomaterials. By using intensity of constituent peaks in the XRD pattern, the compositions of nanocomposites were determined. From the BET analysis, the prepared materials show mesoporous behavior, type Ⅳ curves along with H4 hysteresis. The ZnO/ZnS/α-Fe2O3 composite shows the largest surface area among three materials. From the UV-visible spectra, the band gap energy of the materials was determined. Photoluminescence spectra（PL） were used to determine the emission behavior and surface defects in the materials. In PL spectra, the intensity of UV peak of ZnO/ZnS is lowered than that of ZnO while in case of ZnO/ZnS/α-Fe2O3, the intensity further decreased. The visible emission spectra of ZnO/ZnS increased compared with ZnO while in ZnO/ZnS/α-Fe2O3 it is further increased compared with ZnO/ZnS. The as-synthesized materials were used as photocatalysts for the degradation of dye MeO. The photo-degradation data revealed that the ZnO/ZnS/α-Fe2O3 is the best photocatalyst among three specimens for the degradation of dye MeO. The decrease of intensity of UV emission peak and the increase of intensity of visible emission cause the decrease of recombination of electrons and holes which are ultimately responsible for the highest photocatalytic activity of ZnO/ZnS/α-Fe2O3.展开更多
Rechargeable lithium–oxygen batteries have been considered as a promising energy storage technology because of their ultra-high theoretical energy densities which are comparable to gasoline. In order to improve the e...Rechargeable lithium–oxygen batteries have been considered as a promising energy storage technology because of their ultra-high theoretical energy densities which are comparable to gasoline. In order to improve the electrochemical properties of lithium–oxygen batteries(LOBs), especially the cycling performance, a high-efficiency cathode catalyst is the most important component.Hence, we aim to demonstrate that CuCr_2O_4@rGO(CCO@rGO) nanocomposites, which are synthesized using a facile hydrothermal method and followed by a series of calcination processes, are an effective cathode catalyst. The obtained CCO@rGO nanocomposites which served as the cathode catalyst of the LOBs exhibited an outstanding cycling performance for over 100 cycles with a fixed capacity of 1000 mAh g^(-1) at a current density of 200 mA g^(-1). The enhanced properties were attributed to the synergistic effect between the high catalytic efficiency of the spinel-structured CCO nanoparticles, the high specific surface area, and high conductivity of the rGO.展开更多
Gamma irradiation is employed for in situ preparation of PVA-PANI-ZnS nanocomposite. The irradiation dose is varied from 10 to 40 kGy at 10 kGy intervals. The XRD result confirms the formation of crystalline phases co...Gamma irradiation is employed for in situ preparation of PVA-PANI-ZnS nanocomposite. The irradiation dose is varied from 10 to 40 kGy at 10 kGy intervals. The XRD result confirms the formation of crystalline phases corresponding to ZnS nanoparticles, PVA and PANI. Field emission scanning electron microscopy shows the formation of agglomerated PANI along the PVA backbone, within which the ZnS nanoparticles are dispersed.UV-visible spectroscopy is conducted to measure the transmittance spectra of samples revealing the electronic absorption characteristics of ZnS and PANI nanoparticles. Photo-acoustic（PA） setup is installed to investigate the thermal properties of samples. The PA spectroscopy indicates a high value of thermal diffusivity for samples due to the presence of ZnS and PANI nanoparticles. Moreover, at higher doses, the more polymerization and formation of PANI and ZnS nanoparticles result in enhancement of thermal diffusivity.展开更多
Zinc oxide/low-density polyethylene （LDPE） nanocomposites were prepared for intrauterine devices. The change of Zn^2＋ release rates of nanocomposites （ doped with various mass fractions of zinc oxide nanoparticles...Zinc oxide/low-density polyethylene （LDPE） nanocomposites were prepared for intrauterine devices. The change of Zn^2＋ release rates of nanocomposites （ doped with various mass fractions of zinc oxide nanoparticles between 5wt% and 65 wt% ） for 264 days in a simulated uterine solution were investigated. The resuits show that initial burst phases are followed by near zero-order release phases. SEM technique was employed to observe the surface morphology of the 45wt% ZnO/ LDPE composite. Elements and phases on the surface of the nanocomposite after incubation were also analyzed by EDX and XRD respectively. The experimental results show that incrustation formation does not occur after incubation.展开更多
OBJECTIVE Zn-doped CuO nanocomposites(nZn-CuO NPs) are novel nanoparticles synthesized by sonochemical method.This study aimed to further investigate the antitumor effects and mechanism of nZn-CuO NPs,as well as the e...OBJECTIVE Zn-doped CuO nanocomposites(nZn-CuO NPs) are novel nanoparticles synthesized by sonochemical method.This study aimed to further investigate the antitumor effects and mechanism of nZn-CuO NPs,as well as the exact mechanism of reactive oxygen species(ROS) on nZn-CuO NPs-induced death using N-acetylcysteine(NAC).METHODS The antitumor effects of nZn-CuO NPs were evaluated by MTS assay and orthotopic transplantation tumor model in nude mice.The effects of nZn-CuO NPs with or without NAC on ROS production,DNA damage,apoptosis,mitochondrial damage,autophagy,lysosome impairment,and ER and Golgi stress were determined.Also,western blot was used to detect apoptosis and autophagy related proteins,as well as NF-κB pathway related proteins.RESULTS nZn-CuO NPs significantly inhibit tumor growth both in vitro and in vivo.nZn-CuO NPs were able to cause cytotoxicity,ROS production,DAN damage mitochondrial damage,apoptosis,and autophagy,and NAC can attenuate them.Further studies showed that nZn-CuO NPs induced changes of apoptosis,autophagy and NF-κB pathway related proteins,and NAC can restore them.CONCLUSION Overall,our data demonstrated that nZn-CuO NPs could inhibit tumor growth both in vitro and in vivo by ROS-dependent regulation of apoptosis and autophagy,which might be cross-linked by NF-κB pathways.展开更多
Unique ZnS nanobuns decorated with reduced graphene oxide （ROO） was synthesized and found to exhibit a synergetic effect as a highly efficient and low-cost counter electrode （CE） in dye-sensitized solar cells （D...Unique ZnS nanobuns decorated with reduced graphene oxide （ROO） was synthesized and found to exhibit a synergetic effect as a highly efficient and low-cost counter electrode （CE） in dye-sensitized solar cells （DSCs）. Using this ZnS-ROO CE, a power conversion efficiency （PCE） of 7.03% was achieved. This value was 53% and 41 % higher than those of pure ZnS and ROO CEs, respectively. The ZnS-ROO nanocomposite is indeed an efficient and cost-effective Pt-like alternative for iodine reduction reaction.展开更多
Reduced graphene oxide(rGO)has been widely used to fabricate electronics,sensors,photodetectors,and in other applications.However,the antibacterial performance of pristine rGO is relatively weak.The application of rGO...Reduced graphene oxide(rGO)has been widely used to fabricate electronics,sensors,photodetectors,and in other applications.However,the antibacterial performance of pristine rGO is relatively weak.The application of rGO in biomedical devices,smart food packaging,and water desalination membranes requires further improvement of rGO’s antibacterial abilities.Copper(I)oxide(Cu2O)is an effective antibacterial agent,which denatures protein and enhances the permeability of cell membranes.In this work,we report a simple method of synthesizing a highly antibacterial rGO/Cu2O nanocomposite from cellulose acetate,a derivative of abundant natural cellulose.The synthesized rGO/Cu2O nanocomposite was thoroughly characterized by Raman spectroscopy,X-ray powder diffraction(XRD),X-ray photoelectron spectroscopy(XPS),atomic force microscopy(AFM),scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM),and scanning transmission electron microscopy(STEM).Then,the antibacterial abilities of rGO/Cu2O nanocomposite were evaluated and a bactericidal mechanism was revealed from the molecular biology perspective.Results indicate that our synthesized rGO/Cu2O nanocomposite owns strong antibacterial activity,mainly stemming from the uniformly incorporated Cu2O nanocrystals with a lateral size of 5–40 nm.展开更多
An electrochemical biosensing platform was developed based on glucose oxidase(GOx)/Fe3O4-reduced graphene oxide(Fe3O4-RGO) nanosheets loaded on the magnetic glassy carbon electrode(MGCE).With the advantages of the mag...An electrochemical biosensing platform was developed based on glucose oxidase(GOx)/Fe3O4-reduced graphene oxide(Fe3O4-RGO) nanosheets loaded on the magnetic glassy carbon electrode(MGCE).With the advantages of the magnetism, conductivity and biocompatibility of the Fe3O4-RGO nanosheets, the nanocomposites could be facilely adhered to the electrode surface by magnetically controllable assembling and beneficial to achieve the direct redox reactions and electrocatalytic behaviors of GOx immobilized into the nanocomposites. The biosensor exhibited good electrocatalytic activity, high sensitivity and stability. The current response is linear over glucose concentration ranging from 0.05 to 1.5 m M with a low detection limit of0.15 μM. Meanwhile, validation of the applicability of the biosensor was carried out by determining glucose in serum samples. The proposed protocol is simple, inexpensive and convenient, which shows great potential in biosensing application.展开更多
文摘ZnS/graphene nanocomposites with different graphene concentrations （5, 10 and 15 wt.%） were synthesized using L-cysteine as surfactant and graphene oxide （GO） powders as graphene source. Excellent performance for nanocomposites to remove methylene blue （MB） dye and hexavalent chromium （Cr（VI）） under visible-light illumina- tion was revealed. TEM images showed that ZnS NPs were decorated on GO sheets and the GO caused a significant decrease in the ZnS diameter size. XRD patterns, XPS and FTIR spectroscopy results indicated that GO sheets changed into reduced graphene oxide （rGO） during the synthesis process. Photocurrent measurements under a visible- light source indicated a good chemical reaction between ZnS NPs and rGO sheets.
文摘In order to achieve effective, economic, and easily achievable photocatalyst for the degradation of dye methyl orange（MeO）, ZnO, ZnO/ZnS and ZnO/ZnS/α-Fe2O3 nanocomposites were prepared by simple chemical synthetic route in the aqueous medium. Phase, crystallinity, surface structure and surface behavior of the synthesized materials were determined by X-ray diffraction（XRD） and Brunauer-Emmett-Teller analysis（BET） techniques. XRD study established formation of good crystalline ZnO, ZnO/ZnS and ZnO/ZnS/α-Fe2O3 nanomaterials. By using intensity of constituent peaks in the XRD pattern, the compositions of nanocomposites were determined. From the BET analysis, the prepared materials show mesoporous behavior, type Ⅳ curves along with H4 hysteresis. The ZnO/ZnS/α-Fe2O3 composite shows the largest surface area among three materials. From the UV-visible spectra, the band gap energy of the materials was determined. Photoluminescence spectra（PL） were used to determine the emission behavior and surface defects in the materials. In PL spectra, the intensity of UV peak of ZnO/ZnS is lowered than that of ZnO while in case of ZnO/ZnS/α-Fe2O3, the intensity further decreased. The visible emission spectra of ZnO/ZnS increased compared with ZnO while in ZnO/ZnS/α-Fe2O3 it is further increased compared with ZnO/ZnS. The as-synthesized materials were used as photocatalysts for the degradation of dye MeO. The photo-degradation data revealed that the ZnO/ZnS/α-Fe2O3 is the best photocatalyst among three specimens for the degradation of dye MeO. The decrease of intensity of UV emission peak and the increase of intensity of visible emission cause the decrease of recombination of electrons and holes which are ultimately responsible for the highest photocatalytic activity of ZnO/ZnS/α-Fe2O3.
基金jointly supported by National Science Foundation of China (Grant Numbers: 11572271 and 51302236)the Principal Fund of Xiamen University (Hosted by Guanghui Yue, 2018)
文摘Rechargeable lithium–oxygen batteries have been considered as a promising energy storage technology because of their ultra-high theoretical energy densities which are comparable to gasoline. In order to improve the electrochemical properties of lithium–oxygen batteries(LOBs), especially the cycling performance, a high-efficiency cathode catalyst is the most important component.Hence, we aim to demonstrate that CuCr_2O_4@rGO(CCO@rGO) nanocomposites, which are synthesized using a facile hydrothermal method and followed by a series of calcination processes, are an effective cathode catalyst. The obtained CCO@rGO nanocomposites which served as the cathode catalyst of the LOBs exhibited an outstanding cycling performance for over 100 cycles with a fixed capacity of 1000 mAh g^(-1) at a current density of 200 mA g^(-1). The enhanced properties were attributed to the synergistic effect between the high catalytic efficiency of the spinel-structured CCO nanoparticles, the high specific surface area, and high conductivity of the rGO.
文摘Gamma irradiation is employed for in situ preparation of PVA-PANI-ZnS nanocomposite. The irradiation dose is varied from 10 to 40 kGy at 10 kGy intervals. The XRD result confirms the formation of crystalline phases corresponding to ZnS nanoparticles, PVA and PANI. Field emission scanning electron microscopy shows the formation of agglomerated PANI along the PVA backbone, within which the ZnS nanoparticles are dispersed.UV-visible spectroscopy is conducted to measure the transmittance spectra of samples revealing the electronic absorption characteristics of ZnS and PANI nanoparticles. Photo-acoustic（PA） setup is installed to investigate the thermal properties of samples. The PA spectroscopy indicates a high value of thermal diffusivity for samples due to the presence of ZnS and PANI nanoparticles. Moreover, at higher doses, the more polymerization and formation of PANI and ZnS nanoparticles result in enhancement of thermal diffusivity.
文摘Zinc oxide/low-density polyethylene （LDPE） nanocomposites were prepared for intrauterine devices. The change of Zn^2＋ release rates of nanocomposites （ doped with various mass fractions of zinc oxide nanoparticles between 5wt% and 65 wt% ） for 264 days in a simulated uterine solution were investigated. The resuits show that initial burst phases are followed by near zero-order release phases. SEM technique was employed to observe the surface morphology of the 45wt% ZnO/ LDPE composite. Elements and phases on the surface of the nanocomposite after incubation were also analyzed by EDX and XRD respectively. The experimental results show that incrustation formation does not occur after incubation.
基金supported by Natural Science Foundation of China(81774191) Beijing Natural Science Foundation(7172031) Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th5-year Plan(CIT＆TCD201804086)
文摘OBJECTIVE Zn-doped CuO nanocomposites(nZn-CuO NPs) are novel nanoparticles synthesized by sonochemical method.This study aimed to further investigate the antitumor effects and mechanism of nZn-CuO NPs,as well as the exact mechanism of reactive oxygen species(ROS) on nZn-CuO NPs-induced death using N-acetylcysteine(NAC).METHODS The antitumor effects of nZn-CuO NPs were evaluated by MTS assay and orthotopic transplantation tumor model in nude mice.The effects of nZn-CuO NPs with or without NAC on ROS production,DNA damage,apoptosis,mitochondrial damage,autophagy,lysosome impairment,and ER and Golgi stress were determined.Also,western blot was used to detect apoptosis and autophagy related proteins,as well as NF-κB pathway related proteins.RESULTS nZn-CuO NPs significantly inhibit tumor growth both in vitro and in vivo.nZn-CuO NPs were able to cause cytotoxicity,ROS production,DAN damage mitochondrial damage,apoptosis,and autophagy,and NAC can attenuate them.Further studies showed that nZn-CuO NPs induced changes of apoptosis,autophagy and NF-κB pathway related proteins,and NAC can restore them.CONCLUSION Overall,our data demonstrated that nZn-CuO NPs could inhibit tumor growth both in vitro and in vivo by ROS-dependent regulation of apoptosis and autophagy,which might be cross-linked by NF-κB pathways.
基金supported by the National Natural Science Foundation of China(Grant No.51172102,51302125 and 51303076)
文摘Unique ZnS nanobuns decorated with reduced graphene oxide （ROO） was synthesized and found to exhibit a synergetic effect as a highly efficient and low-cost counter electrode （CE） in dye-sensitized solar cells （DSCs）. Using this ZnS-ROO CE, a power conversion efficiency （PCE） of 7.03% was achieved. This value was 53% and 41 % higher than those of pure ZnS and ROO CEs, respectively. The ZnS-ROO nanocomposite is indeed an efficient and cost-effective Pt-like alternative for iodine reduction reaction.
文摘Reduced graphene oxide(rGO)has been widely used to fabricate electronics,sensors,photodetectors,and in other applications.However,the antibacterial performance of pristine rGO is relatively weak.The application of rGO in biomedical devices,smart food packaging,and water desalination membranes requires further improvement of rGO’s antibacterial abilities.Copper(I)oxide(Cu2O)is an effective antibacterial agent,which denatures protein and enhances the permeability of cell membranes.In this work,we report a simple method of synthesizing a highly antibacterial rGO/Cu2O nanocomposite from cellulose acetate,a derivative of abundant natural cellulose.The synthesized rGO/Cu2O nanocomposite was thoroughly characterized by Raman spectroscopy,X-ray powder diffraction(XRD),X-ray photoelectron spectroscopy(XPS),atomic force microscopy(AFM),scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM),and scanning transmission electron microscopy(STEM).Then,the antibacterial abilities of rGO/Cu2O nanocomposite were evaluated and a bactericidal mechanism was revealed from the molecular biology perspective.Results indicate that our synthesized rGO/Cu2O nanocomposite owns strong antibacterial activity,mainly stemming from the uniformly incorporated Cu2O nanocrystals with a lateral size of 5–40 nm.
基金supported by the National Natural Science Foundation of China (21373138)Shanghai Sci. & Tech. Committee (12JC1407200)Program for Changjiang Scholars and Innovative Research Team in University (IRT1269)
文摘An electrochemical biosensing platform was developed based on glucose oxidase(GOx)/Fe3O4-reduced graphene oxide(Fe3O4-RGO) nanosheets loaded on the magnetic glassy carbon electrode(MGCE).With the advantages of the magnetism, conductivity and biocompatibility of the Fe3O4-RGO nanosheets, the nanocomposites could be facilely adhered to the electrode surface by magnetically controllable assembling and beneficial to achieve the direct redox reactions and electrocatalytic behaviors of GOx immobilized into the nanocomposites. The biosensor exhibited good electrocatalytic activity, high sensitivity and stability. The current response is linear over glucose concentration ranging from 0.05 to 1.5 m M with a low detection limit of0.15 μM. Meanwhile, validation of the applicability of the biosensor was carried out by determining glucose in serum samples. The proposed protocol is simple, inexpensive and convenient, which shows great potential in biosensing application.
