Water splitting is an environment friendly and efficient way to produce hydrogen.Highly efficient and low-cost non-noble metal catalysts play an important role in hydrogen evolution reaction(HER).Dealloying is a simpl...Water splitting is an environment friendly and efficient way to produce hydrogen.Highly efficient and low-cost non-noble metal catalysts play an important role in hydrogen evolution reaction(HER).Dealloying is a simple method to prepare three-dimensional self-supporting nanoporous materials without conductive supports and binders.In this work,we prepared self-supporting nanoporous CoBP electrocatalyst by dealloying method.The influence of the synergistic effect of nonmetallic elements on catalytic activity was investigated.The synergistic electronic effect of Co,B and P atoms on the surface optimizes the H atoms desorption and results in superior HER activity.The bi-continuous structure of nanoporous CoBP provides more active area and favors of electron and electrolyte transfer.The nanoporous CoBP with the B/P atomic ratio of 1/3 exhibits low overpotential of 42 mV at 10 mA·cm^(-2),small Tafel slope of 39.8 mV·dec-1 and good long-term stability with no performance decrease for 20 h in alkaline solution.展开更多
NiMo-based materials have been identified as potential candidates of Pt/C electrocatalysts for hydrogen evolution reaction(HER)due to appropriate binding energy to hydrogen,and good resistance to corrosive environment...NiMo-based materials have been identified as potential candidates of Pt/C electrocatalysts for hydrogen evolution reaction(HER)due to appropriate binding energy to hydrogen,and good resistance to corrosive environments.However,little work has been carried out to enhance the catalytic performance in large-scale water-alkali electrolysis.The NoMo amorphous coating,as a highefficient and cost-effective catalyst toward HER,was synthesized by a facile electrodeposition strategy in this study.The effects of the pH value of electrolyte on the structure and HER activity of NiMo coating were investigated.The as-prepared NiMo_((pH10))exhibited the highest HER activity with overpotentials of 63.9 and 157.1 mV(vs.RHE,with 80%potential drop due to electrical resistance(iR)compensation)at the current density of-10 mA·cm^(-2)and-100 mA·cm^(-2).This NiMo_((pH10))coating also had excellent long-term durability of up to100 h stable operation under the constant current density of-100 mA·cm^(-2).The rapid HER kinetics and outstanding endurance can be ascribed to the NiMo compact coating with amorphous structures as well as good contact between NiMo coating and Ni foam substrate,endowing it grand feasibility in practical industrial applications.展开更多
Pathogenic bacteria have been threatening the daily life of human beings.More effective methods without causing drug-resistance of bacteria need to be developed to fight against these pathogens.Herein,flower-like CuS/...Pathogenic bacteria have been threatening the daily life of human beings.More effective methods without causing drug-resistance of bacteria need to be developed to fight against these pathogens.Herein,flower-like CuS/-graphene oxide(GO)hybrids have been successfully synthesized via simple one-pot hydrothermal process.GO worked as an excellent electron acceptor to transport the photogenerated electrons from CuS,which can suppress the recombination of hole–electron pairs efficiently,thus enhancing the photocatalytic property.In addition,the morphology of CuS and GO with high specific surface area and the increased defect in GO also improved photocatalytic performance of the hybrid.Owing to the synergy of photothermal,enhanced photocatalytic effect and released Cu ions,CuS/GO exhibited outstanding antibacterial efficacy under visible light irradiation for 15 min.Additionally,the hybrid showed great biocompatibility to L929 cell.Hence,the synthesized CuS/GO would be a promising antibacterial material for daily life including rapid water disinfection and wounds sterilization.展开更多
In this paper, a thin calcium phosphate layer was prepared on the surface of Ti4oZr10Cu36Pd14 bulk metallic glasses (BMGs). All samples were dipped in HNO3 aqueous solution and boiled in 1.2 mol-L-I NaOH aqueous sol...In this paper, a thin calcium phosphate layer was prepared on the surface of Ti4oZr10Cu36Pd14 bulk metallic glasses (BMGs). All samples were dipped in HNO3 aqueous solution and boiled in 1.2 mol-L-I NaOH aqueous solution. After the two preliminary treatment steps, they were soaked in simulated body fluid (SBF) to form an apatite layer on the surface. After immersion for 12 days, a coating composed mainly of Ca-P particles was rapidly deposited on the surface of Ti40Zr10Cu36Pd14 bulk metallic glasses. The surfaces of chemically treated sam- ples and the samples after immersion in SBF were char- acterized by X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and energy dispersive spectroscopy (EDS). Analysis results indicate that this apatite coating consists of Ca-P particles with different diameters. In addition, the Ca/P ratio of the apatite coatings immersed for 14 days is 1.62, which is close to that of hydroxyapatite (HA).展开更多
The daily life of people in the intelligent age is inseparable from electronic device,and a number of bacteria on touch screens are increasingly threatening the health of users.Herein,a photocatalytic TiO_(2)/Ag thin ...The daily life of people in the intelligent age is inseparable from electronic device,and a number of bacteria on touch screens are increasingly threatening the health of users.Herein,a photocatalytic TiO_(2)/Ag thin film was synthesized on a glass by atomic layer deposition and subsequent in situ reduction.Ultraviolet-visible(UV-Vis)spectra showed that this film can harvest the simulated solar light more efficiently than that of pristine TiO_(2).The antibacterial tests in vitro showed that the antibacterial efficiency of the TiO_(2)/Ag film against S.aureus and E.coli was 98.2%and 98.6%,under visible light irradiation for 5 min.The underlying mechanism was that the in-situ reduction of Ag on the surface of TiO_(2)reduced the bandgap of TiO_(2)from 3.44 to 2.61 eV due to the formation of Schottky heterojunction at the interface between TiO_(2)and Ag.Thus,TiO_(2)/Ag can generate more reactive oxygen species for bacterial inactivation on the surface of electronic screens.More importantly,the TiO_(2)/Ag film had great biocompatibility with/without light irradiation.The platform not only provides a more convenient choice for the traditional antibacterial mode but also has limitless possibilities for application in the field of billions of touch screens.展开更多
Controlling the corrosion rate is critical for practical applications of Mg-based alloys. In this work, we constructed a protective coating of hybrid polycaprolactone(H-PCL)/indocyanine green(ICG) on AZ31 Mg alloy,who...Controlling the corrosion rate is critical for practical applications of Mg-based alloys. In this work, we constructed a protective coating of hybrid polycaprolactone(H-PCL)/indocyanine green(ICG) on AZ31 Mg alloy,whose degradation rate was controlled by 808-nm nearinfrared(NIR) light irradiation. The corrosion behaviors of H-PCL/ICG coated Mg alloys were systematically investigated by potentiodynamic polarization tests, electrochemical impedance spectroscopy(EIS) and hydrogen evolution experiments. The results disclosed that the H-PCL/ICG composite coating could effectively protect Mg alloy from corroding without NIR light irradiation. In contrast, under 808-nm NIR light irradiation, the corrosion resistance of this composite coating was decreased significantly, i.e., the corrosion current density(i_(corr))increasedfrom(8.81 ± 1.068) 9 10^(-8) to(1.22 ± 0.545) 9 10^(-6) A·cm^(-2). This is because the component of ICG in the coating was excited to produce heat locally, which triggered the glass transition temperature(T_(g)) of H-PCL in the coating, resulting in the motion of the molecular chain segment. Consequently, the electrolytes penetrated the coating and corroded the Mg substrate. In vitro biological experiment indicated that the synthesized coating exhibited good cytocompatibility.Hence, these findings will provide a new strategy for designing novel photoresponsive coatings to remotely adjust the degradation rate of biodegradable metals for biomedical applications.展开更多
The Ti_(51.44)Zr_(16.26)Cu_(30)Sn_(2.3)(at%)amorphous filler alloy in a ribbon form was prepared by melt spinning.The Ti-6 Al-4 V alloy was brazed in vacuum furnace by using the Ti_(51.44)Zr_(16.26)Cu_(30)Sn_(2.3)amor...The Ti_(51.44)Zr_(16.26)Cu_(30)Sn_(2.3)(at%)amorphous filler alloy in a ribbon form was prepared by melt spinning.The Ti-6 Al-4 V alloy was brazed in vacuum furnace by using the Ti_(51.44)Zr_(16.26)Cu_(30)Sn_(2.3)amorphous filler alloy.The effects of brazing temperature and holding time on the interfacial microstructure and mechanical properties of the Ti-6 Al-4 V brazed joints were investigated.The brazed joints are composed ofα-Ti,β-Ti,and(Ti,Zr)_(2)Cu phases.The shear strength of the joints increases with brazing temperature increasing from 1153 to 1193 K and holding time from 10 to 15 min,while decreases with brazing temperature and time further increasing.Low temperature brazing results in the formation of microcracks and voids in the seams,which are harmful for the shear strength of the joints.In the joint brazed at 1193 K for 15 min,a fineα+βWidmansta¨tten structure beneficial to the mechanical property is formed,and the joint exhibits relatively high joint strength of 180 MPa.展开更多
In this work,amorphous Zr_(55)Al_(10)Ni_(5)Cu_(30)alloy thin film was prepared on D36 steel substrate by magnetron sputtering method.The film was characterized by scanning electron microscopy(SEM),X-ray diffraction(XR...In this work,amorphous Zr_(55)Al_(10)Ni_(5)Cu_(30)alloy thin film was prepared on D36 steel substrate by magnetron sputtering method.The film was characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),atomic force microscopy(AFM),hardness tester and nano indentation.Corrosion behavior of the film was investigated in 3.5%NaCl aqueous solutions by an electrochemical method.At room temperature,the amorphous alloy film was formed completely after sputtering for 5 h.The surface morphology of the amorphous alloy film was uniform and smooth.Formation of the amorphous alloy film improved the microhardness and corrosion resistance of the D36 substrate.The amorphous alloy film(prepared at room temperature for 5 h)exhibited good adhesion strength with the substrate.The as-sputtered sample exhibited a crevice corrosion trend when the sputtering time was too short(1 h)or too long(10 h).展开更多
基金financially supported by the National Natural Science Foundation of China(No.51771131)。
文摘Water splitting is an environment friendly and efficient way to produce hydrogen.Highly efficient and low-cost non-noble metal catalysts play an important role in hydrogen evolution reaction(HER).Dealloying is a simple method to prepare three-dimensional self-supporting nanoporous materials without conductive supports and binders.In this work,we prepared self-supporting nanoporous CoBP electrocatalyst by dealloying method.The influence of the synergistic effect of nonmetallic elements on catalytic activity was investigated.The synergistic electronic effect of Co,B and P atoms on the surface optimizes the H atoms desorption and results in superior HER activity.The bi-continuous structure of nanoporous CoBP provides more active area and favors of electron and electrolyte transfer.The nanoporous CoBP with the B/P atomic ratio of 1/3 exhibits low overpotential of 42 mV at 10 mA·cm^(-2),small Tafel slope of 39.8 mV·dec-1 and good long-term stability with no performance decrease for 20 h in alkaline solution.
基金financially supported by the National Natural Science Foundation of China (No.51771131)
文摘NiMo-based materials have been identified as potential candidates of Pt/C electrocatalysts for hydrogen evolution reaction(HER)due to appropriate binding energy to hydrogen,and good resistance to corrosive environments.However,little work has been carried out to enhance the catalytic performance in large-scale water-alkali electrolysis.The NoMo amorphous coating,as a highefficient and cost-effective catalyst toward HER,was synthesized by a facile electrodeposition strategy in this study.The effects of the pH value of electrolyte on the structure and HER activity of NiMo coating were investigated.The as-prepared NiMo_((pH10))exhibited the highest HER activity with overpotentials of 63.9 and 157.1 mV(vs.RHE,with 80%potential drop due to electrical resistance(iR)compensation)at the current density of-10 mA·cm^(-2)and-100 mA·cm^(-2).This NiMo_((pH10))coating also had excellent long-term durability of up to100 h stable operation under the constant current density of-100 mA·cm^(-2).The rapid HER kinetics and outstanding endurance can be ascribed to the NiMo compact coating with amorphous structures as well as good contact between NiMo coating and Ni foam substrate,endowing it grand feasibility in practical industrial applications.
基金This work was financially supported by the National Science Fund for Distinguished Young Scholars(No.51925104)the National Natural Science Foundation of China(Nos.51871162 and 51671081)。
文摘Pathogenic bacteria have been threatening the daily life of human beings.More effective methods without causing drug-resistance of bacteria need to be developed to fight against these pathogens.Herein,flower-like CuS/-graphene oxide(GO)hybrids have been successfully synthesized via simple one-pot hydrothermal process.GO worked as an excellent electron acceptor to transport the photogenerated electrons from CuS,which can suppress the recombination of hole–electron pairs efficiently,thus enhancing the photocatalytic property.In addition,the morphology of CuS and GO with high specific surface area and the increased defect in GO also improved photocatalytic performance of the hybrid.Owing to the synergy of photothermal,enhanced photocatalytic effect and released Cu ions,CuS/GO exhibited outstanding antibacterial efficacy under visible light irradiation for 15 min.Additionally,the hybrid showed great biocompatibility to L929 cell.Hence,the synthesized CuS/GO would be a promising antibacterial material for daily life including rapid water disinfection and wounds sterilization.
基金financially supported by the Key Project in the Science & Technology Pillar Program of Tianjin (No. 09ZCKFGX29100)the Research Fund for the Doctoral Program of Higher Education of China (No. 20110032110023)
文摘In this paper, a thin calcium phosphate layer was prepared on the surface of Ti4oZr10Cu36Pd14 bulk metallic glasses (BMGs). All samples were dipped in HNO3 aqueous solution and boiled in 1.2 mol-L-I NaOH aqueous solution. After the two preliminary treatment steps, they were soaked in simulated body fluid (SBF) to form an apatite layer on the surface. After immersion for 12 days, a coating composed mainly of Ca-P particles was rapidly deposited on the surface of Ti40Zr10Cu36Pd14 bulk metallic glasses. The surfaces of chemically treated sam- ples and the samples after immersion in SBF were char- acterized by X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and energy dispersive spectroscopy (EDS). Analysis results indicate that this apatite coating consists of Ca-P particles with different diameters. In addition, the Ca/P ratio of the apatite coatings immersed for 14 days is 1.62, which is close to that of hydroxyapatite (HA).
基金financially supported by the National Natural Science Foundation of China(Nos.82002303,51871162 and 51932002)the China National Funds for Distinguished Young Scientists(No.51925104)+2 种基金Scientific Research Foundation of Peking University Shenzhen Hospital(No.KYQD2021064)Beijing Municipal Health Commission(Nos.BMHC-2021-6,BMHC-2019-9,BMHC-2018-4 and PXM2020_026275_000002)the National Key R&D Program of China(No.R&D#2018YFA0703100)
文摘The daily life of people in the intelligent age is inseparable from electronic device,and a number of bacteria on touch screens are increasingly threatening the health of users.Herein,a photocatalytic TiO_(2)/Ag thin film was synthesized on a glass by atomic layer deposition and subsequent in situ reduction.Ultraviolet-visible(UV-Vis)spectra showed that this film can harvest the simulated solar light more efficiently than that of pristine TiO_(2).The antibacterial tests in vitro showed that the antibacterial efficiency of the TiO_(2)/Ag film against S.aureus and E.coli was 98.2%and 98.6%,under visible light irradiation for 5 min.The underlying mechanism was that the in-situ reduction of Ag on the surface of TiO_(2)reduced the bandgap of TiO_(2)from 3.44 to 2.61 eV due to the formation of Schottky heterojunction at the interface between TiO_(2)and Ag.Thus,TiO_(2)/Ag can generate more reactive oxygen species for bacterial inactivation on the surface of electronic screens.More importantly,the TiO_(2)/Ag film had great biocompatibility with/without light irradiation.The platform not only provides a more convenient choice for the traditional antibacterial mode but also has limitless possibilities for application in the field of billions of touch screens.
基金jointly supported by the Natural Science Fund of Hubei Province(No.2018CFA064)the National Natural Science Foundation of China(Nos.51871162 and 51671081)+3 种基金the National Science Fund for Distinguished Young Scholars(No.51925104)the Key Program of National Natural Science Foundation of China(No.51631007)Hong Kong ITC(Nos.ITS/287/17 and GHX/002/14SZ)the Health and Medical Research Fund(No.03142446)。
文摘Controlling the corrosion rate is critical for practical applications of Mg-based alloys. In this work, we constructed a protective coating of hybrid polycaprolactone(H-PCL)/indocyanine green(ICG) on AZ31 Mg alloy,whose degradation rate was controlled by 808-nm nearinfrared(NIR) light irradiation. The corrosion behaviors of H-PCL/ICG coated Mg alloys were systematically investigated by potentiodynamic polarization tests, electrochemical impedance spectroscopy(EIS) and hydrogen evolution experiments. The results disclosed that the H-PCL/ICG composite coating could effectively protect Mg alloy from corroding without NIR light irradiation. In contrast, under 808-nm NIR light irradiation, the corrosion resistance of this composite coating was decreased significantly, i.e., the corrosion current density(i_(corr))increasedfrom(8.81 ± 1.068) 9 10^(-8) to(1.22 ± 0.545) 9 10^(-6) A·cm^(-2). This is because the component of ICG in the coating was excited to produce heat locally, which triggered the glass transition temperature(T_(g)) of H-PCL in the coating, resulting in the motion of the molecular chain segment. Consequently, the electrolytes penetrated the coating and corroded the Mg substrate. In vitro biological experiment indicated that the synthesized coating exhibited good cytocompatibility.Hence, these findings will provide a new strategy for designing novel photoresponsive coatings to remotely adjust the degradation rate of biodegradable metals for biomedical applications.
基金the Key Project of Natural Science Foundation of Tianjin City(No.14JCZDJC38600)。
文摘The Ti_(51.44)Zr_(16.26)Cu_(30)Sn_(2.3)(at%)amorphous filler alloy in a ribbon form was prepared by melt spinning.The Ti-6 Al-4 V alloy was brazed in vacuum furnace by using the Ti_(51.44)Zr_(16.26)Cu_(30)Sn_(2.3)amorphous filler alloy.The effects of brazing temperature and holding time on the interfacial microstructure and mechanical properties of the Ti-6 Al-4 V brazed joints were investigated.The brazed joints are composed ofα-Ti,β-Ti,and(Ti,Zr)_(2)Cu phases.The shear strength of the joints increases with brazing temperature increasing from 1153 to 1193 K and holding time from 10 to 15 min,while decreases with brazing temperature and time further increasing.Low temperature brazing results in the formation of microcracks and voids in the seams,which are harmful for the shear strength of the joints.In the joint brazed at 1193 K for 15 min,a fineα+βWidmansta¨tten structure beneficial to the mechanical property is formed,and the joint exhibits relatively high joint strength of 180 MPa.
基金financially supported by the National Natural Science Foundation of China(No.51771131)。
文摘In this work,amorphous Zr_(55)Al_(10)Ni_(5)Cu_(30)alloy thin film was prepared on D36 steel substrate by magnetron sputtering method.The film was characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),atomic force microscopy(AFM),hardness tester and nano indentation.Corrosion behavior of the film was investigated in 3.5%NaCl aqueous solutions by an electrochemical method.At room temperature,the amorphous alloy film was formed completely after sputtering for 5 h.The surface morphology of the amorphous alloy film was uniform and smooth.Formation of the amorphous alloy film improved the microhardness and corrosion resistance of the D36 substrate.The amorphous alloy film(prepared at room temperature for 5 h)exhibited good adhesion strength with the substrate.The as-sputtered sample exhibited a crevice corrosion trend when the sputtering time was too short(1 h)or too long(10 h).