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
Silver as a highly conductive metal is usually doped in YBa2Cu3O7-x superconductor bulks to improve critical current density of YBa2Cu3O7-x superconductor.The valuable metal elements silver,yttrium,barium and copper i...Silver as a highly conductive metal is usually doped in YBa2Cu3O7-x superconductor bulks to improve critical current density of YBa2Cu3O7-x superconductor.The valuable metal elements silver,yttrium,barium and copper in waste YBa2Cu3O7-x/Ag composite superconductor bulks were recovered,respectively.Silver was recovered with process at first,the waste was dissolved by nitric acid and silver chloride was precipitated by adding chloride acid,then silver pig was obtained by melting silver chloride together with sodium carbonate at 1 000℃.The effective factors on recovery ratio and purity of silver were studied.The chemical analysis proves that the purity of silver ingot is 95.86%.The recovery ratio of silver is calculated to be 92.56%.The loss of silver may be due to the loss of silver chloride during filtering and the volatilization of silver when silver chloride and sodium carbonate are smelted at high temperature.For other three metal elements,Y3 +,Ba 2+and Cu 2+,in the surplus waste liquid after recovering silver, they were separated with the sequence of barium,copper and then yttrium step by step.First,sulfate acid was used to precipitate barium sulfate.Then,sodium sulfide was added to the surplus solution so that copper could be separated as copper sulfide.During this separation procedure,it was important to control the pH value to be 1-2.After that,oxalic acid was added into the surplus solution to obtain yttrium oxalate.Finally,yttrium oxide was formed by burning yttrium oxalate.The XRD results indicate that the final products are all single-phase compounds as BaSO4,CuS and Y2O3,respectively.展开更多
Recently,CO2 conversion by electrochemical tool into value-added chemicals has been considered as one of the most promising strategies to offer sustainable development in energy and environment.In this contribution,we...Recently,CO2 conversion by electrochemical tool into value-added chemicals has been considered as one of the most promising strategies to offer sustainable development in energy and environment.In this contribution,we investigated electro-derived composites from Cu-based layered double hydroxide(LDH)for CO2 electrochemical reduction.The Cu-Cu2O based nanocomposite(HPR-LDH)were derived by using electro-strategy from LDH having the stability up to 20 h and selectivity toward C2H4 with faraday efficiency up to 36%by significantly suppressing CH4 and H2 with respect to bulk Cu foil.A highly negative reduction potential derived catalyst(HPR-LDH)maintained long-term stability for the selective production of ethylene over methane,and a small amount of Cu2O was still observed on the catalyst surface after CO2 reduction reaction(CO2RR).Moreover,such unique strategy for electro-derived composite from LDH having small nanoparticles stacked each other grown on layered structure,would provide new insight to improve durability of O-Cu combination catalysts for C-C coupling products during electrochemical CO2conversion by suppressing HER.The XRD,SEM,ESR,and XPS analyses confirmed that the long-term ethylene selectivity of HPR-LDH is due to the presence of subsurface oxygen.The designed composite catalyst significantly enhances the stability and selectivity,and also decreases the over potential for CO2 electroreduction.We predict that the new designed LDH 2D-derived composites may attract new insight for transition metal and may open up a new direction for known structural properties of selective catalyst synthesis regarding effective CO2 reduction reaction.展开更多
Au nanostructures were prepared on uniform Cu2O octahedra and rhombic dodecahedra via the galvanic replacement reaction between HAuCl 4 and Cu2O. The compositions and structures were studied by Scanning Electron Micro...Au nanostructures were prepared on uniform Cu2O octahedra and rhombic dodecahedra via the galvanic replacement reaction between HAuCl 4 and Cu2O. The compositions and structures were studied by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), High-Resolution Transmission Electron Microscope (HRTEM), X-Ray Diffraction (XRD), X-Ray Absorption Spectroscopy (XAS), X-ray Photoelectron Spectroscopy (XPS) and in-situ DRIFTS spectroscopy of CO adsorption. Different from the formation of Au-Cu alloys on Cu2O cubes by the galvanic replacement reaction (ChemNanoMat 2 (2016) 861-865), metallic Au particles and positively-charged Au clusters form on Cu2O octahedra and rhombic dodecahedra at very small Au loadings and only metallic Au particles form at large Au loadings. Metallic Au particles on Cu2O octahedra and rhombic dodecahedra are more active in catalyzing the liquid phase aerobic oxidation reaction of benzyl alcohol than positively-charged Au clusters. These results demonstrate an obvious morphology effect of Cu2O nanocrystals on the liquid-solid interfacial reactions and prove oxide morphology as an effective strategy to tune the surface reactivity and catalytic performance. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
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Project(50702012)supported by the National Natural Science Foundation of ChinaProject(20060145030)supported by Doctoral Foundation of Chinese Education Ministry
文摘Silver as a highly conductive metal is usually doped in YBa2Cu3O7-x superconductor bulks to improve critical current density of YBa2Cu3O7-x superconductor.The valuable metal elements silver,yttrium,barium and copper in waste YBa2Cu3O7-x/Ag composite superconductor bulks were recovered,respectively.Silver was recovered with process at first,the waste was dissolved by nitric acid and silver chloride was precipitated by adding chloride acid,then silver pig was obtained by melting silver chloride together with sodium carbonate at 1 000℃.The effective factors on recovery ratio and purity of silver were studied.The chemical analysis proves that the purity of silver ingot is 95.86%.The recovery ratio of silver is calculated to be 92.56%.The loss of silver may be due to the loss of silver chloride during filtering and the volatilization of silver when silver chloride and sodium carbonate are smelted at high temperature.For other three metal elements,Y3 +,Ba 2+and Cu 2+,in the surplus waste liquid after recovering silver, they were separated with the sequence of barium,copper and then yttrium step by step.First,sulfate acid was used to precipitate barium sulfate.Then,sodium sulfide was added to the surplus solution so that copper could be separated as copper sulfide.During this separation procedure,it was important to control the pH value to be 1-2.After that,oxalic acid was added into the surplus solution to obtain yttrium oxalate.Finally,yttrium oxide was formed by burning yttrium oxalate.The XRD results indicate that the final products are all single-phase compounds as BaSO4,CuS and Y2O3,respectively.
基金the Fundamental Research Funds for the Central Universities(2019YC17)the National Natural Science Foundation of China(U1810209)+1 种基金the International Science and Technology Cooperation Project of Bingtuan(2018BC002)the Beijing Municipal Education Commission for their financial support through Innovative Transdisciplinary Program“Ecological Restoration Engineering”。
文摘Recently,CO2 conversion by electrochemical tool into value-added chemicals has been considered as one of the most promising strategies to offer sustainable development in energy and environment.In this contribution,we investigated electro-derived composites from Cu-based layered double hydroxide(LDH)for CO2 electrochemical reduction.The Cu-Cu2O based nanocomposite(HPR-LDH)were derived by using electro-strategy from LDH having the stability up to 20 h and selectivity toward C2H4 with faraday efficiency up to 36%by significantly suppressing CH4 and H2 with respect to bulk Cu foil.A highly negative reduction potential derived catalyst(HPR-LDH)maintained long-term stability for the selective production of ethylene over methane,and a small amount of Cu2O was still observed on the catalyst surface after CO2 reduction reaction(CO2RR).Moreover,such unique strategy for electro-derived composite from LDH having small nanoparticles stacked each other grown on layered structure,would provide new insight to improve durability of O-Cu combination catalysts for C-C coupling products during electrochemical CO2conversion by suppressing HER.The XRD,SEM,ESR,and XPS analyses confirmed that the long-term ethylene selectivity of HPR-LDH is due to the presence of subsurface oxygen.The designed composite catalyst significantly enhances the stability and selectivity,and also decreases the over potential for CO2 electroreduction.We predict that the new designed LDH 2D-derived composites may attract new insight for transition metal and may open up a new direction for known structural properties of selective catalyst synthesis regarding effective CO2 reduction reaction.
基金supported by the National Basic Research Program of China(2013CB933104)the National Natural Science Foundation of China(21525313,21173204,21373192,U1332113)+1 种基金MOE Fundamental Research Funds for the Central Universities(WK2060030017)Collaborative Innovation Center of Suzhou Nano Science and Technology
文摘Au nanostructures were prepared on uniform Cu2O octahedra and rhombic dodecahedra via the galvanic replacement reaction between HAuCl 4 and Cu2O. The compositions and structures were studied by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), High-Resolution Transmission Electron Microscope (HRTEM), X-Ray Diffraction (XRD), X-Ray Absorption Spectroscopy (XAS), X-ray Photoelectron Spectroscopy (XPS) and in-situ DRIFTS spectroscopy of CO adsorption. Different from the formation of Au-Cu alloys on Cu2O cubes by the galvanic replacement reaction (ChemNanoMat 2 (2016) 861-865), metallic Au particles and positively-charged Au clusters form on Cu2O octahedra and rhombic dodecahedra at very small Au loadings and only metallic Au particles form at large Au loadings. Metallic Au particles on Cu2O octahedra and rhombic dodecahedra are more active in catalyzing the liquid phase aerobic oxidation reaction of benzyl alcohol than positively-charged Au clusters. These results demonstrate an obvious morphology effect of Cu2O nanocrystals on the liquid-solid interfacial reactions and prove oxide morphology as an effective strategy to tune the surface reactivity and catalytic performance. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
