Hydrogen is a clean and flexible energy carrier that has the promising to satisfy urgent demands of the energy crisis and environmental protection.Electrochemical hydrogen evolution reaction(HER),a critical half-react...Hydrogen is a clean and flexible energy carrier that has the promising to satisfy urgent demands of the energy crisis and environmental protection.Electrochemical hydrogen evolution reaction(HER),a critical half-reaction in water splitting,is one of the greenest and most common methods to obtain high-purity hydrogen.Designing preeminent activity and stability electrocatalysts for hydrogen precipitation reac-tion(HER)to reduce energy consumption is of great essential.3D carbon-based materials have attracted widespread concern as the potential scaffolds of highly active and durable electrocatalysts for HER.To boost the HER activity and prolong the lifespan of electrocatalysts,multifarious 3D carbon architectures make an appearance to be engineered for accelerating electronic/mass transfer and maximizing the expo-sure of active sites.Herein,we designed and fabricated high-performance electrocatalysts based on a spe-cial caterpillar-like 3D graphene nanoscrolls@CNTs(GNS@CNTs)scaffold decorated with Co-doped MoSe_(2)nanosheets for HER.In the caterpillar-like hierarchical structure,CNTs were seamlessly co-bonded and dilated the interlayer and outer spacing of GNS through CVD growth technology,and nickel nanoparticles were covered by the CNTs tips.Taking advantage of the plentiful hierarchical pore,larger specific surface area,and higher chemical stability of the caterpillar-like structure,the catalysts exhibited enhanced elec-trocatalytic properties than some existing data reported.Density functional theory calculations showed that the encapsulated nickel nanoparticle could tune the electronic structure of the outer anchored Co-doped MoSe_(2)and optimize itsG of H∗adsorption by electron traversing effect and doping effect.These indicate that caterpillar-like GNS@CNT is an ideal scaffold f or anchoring actives substance and is suit-able for high-efficient HER.This study provides new insights for designing hierarchical carbon composite nanostructures for catalysts,sensors,energy materials,and other applications.展开更多
Attaining a highly efficient and inexpensive electrocatalyst is significant for the hydrogen evolution reaction(HER)but still challenging nowadays.The transition-metal phosphides(TMPs)catalysts with platinum-like elec...Attaining a highly efficient and inexpensive electrocatalyst is significant for the hydrogen evolution reaction(HER)but still challenging nowadays.The transition-metal phosphides(TMPs)catalysts with platinum-like electronic structures are a potential candidate for the HER,but those are prone to be strongly bound with hydrogen intermediates(H∗),resulting in sluggish HER kinetics.Herein we report a unique hybrid structure of CoP anchored on graphene nanoscrolls@carbon nano tubes(CNTs)scaffold(Ni M@C-CoP)encapsulating various Ni M(M=Zn,Mo,Ni,Co)bimetal nanoalloy via chemical vapor deposi-tion(CVD)growth of CNT on graphene nanoscrolls followed by the impregnation of cobalt precursors and phosphorization for efficiently electrocatalytic hydrogen evolution.CoP nanoparticles mainly scattered at the tip of CNT branches which exhibited the analogical“Three-layer core-shell”structures.Experiments and density functional theory(DFT)calculations consistently disclose that the encapsulated various NiMs can offer different numbers of electrons to weaken the interactions of outmost CoP with H∗and push the downshift of the d-band center to different degrees as well as stabilize the outmost CoP nanopar-ticles to gain catalytic stability via the electron traversing effect.The electrocatalytic HER activity can be maximumly enhanced with low overpotentials of 78 mV(alkaline)and 89 mV(acidic)at a current density of 10 mA/cm^(2) and sustained at least 24 h especially for NiZn@C-CoP catalyst.This novel system is distinct from conventional three-layer heterostructure,providing a specially thought of d-band center control engineering strategy for the design of heterogeneous catalysts and expanding to other electrocat-alysts,energy storage,sensing,and other applications.展开更多
The gradient porous Ti3Zr2Sn3Mo25Nb(TLM)alloy rods were fabricated through sintering the alloyed powder to a solid core.The porous sample was then modified by a Micro Arc Oxidation(MAO)treatment in an electrolyte cont...The gradient porous Ti3Zr2Sn3Mo25Nb(TLM)alloy rods were fabricated through sintering the alloyed powder to a solid core.The porous sample was then modified by a Micro Arc Oxidation(MAO)treatment in an electrolyte containing calcium and phosphate,a hydrothermal treatment enabled secondary microporous hydroxyapatite(HA)coating,and a further bone morphogenetic protein-2(BMP-2)loading treatment through immersion and freeze-drying.The treatment led to an orderly secondary microporous coating containing HA nano-particles and evenly distributed BMP-2 in the porous coatings.As a result,osteoblasts could adhere and grow well on the coatings with a high cell adhesion rate and cell functional activity.The in-situ shear testing indicated that the interfacial strength had been enhanced significantly.Improvement of the bond formation and osseointegration with the titanium implant is attributed to increased surface area for the cell to attach,creating voids for the cell to grow in,and activating titanium surface by introducing bioactive ingredients such as HA and BMP-2.展开更多
Waste polyethylene packaging (WPE) was used to modify asphalt, and hot storage stability of the modified asphalt was studied in this paper. The morphological change and component loss of WPE modified asphalt were ch...Waste polyethylene packaging (WPE) was used to modify asphalt, and hot storage stability of the modified asphalt was studied in this paper. The morphological change and component loss of WPE modified asphalt were characterized by fluorescence microscopy, Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetry (TG) and isolation testing. In addition, the mechanism of the hot storage stability of WPE modified asphalt was discussed. The results showed that the modification of asphalt with WPE was a physical process. It was found that the filament or partly network-like structure formed in the modified asphalt system was beneficial to improving the hot storage stability. Moreover, the addition of WPE resulted in a decrease in both the light components volatilization and the macromolecules decomposition of asphalt. It was demonstrated that when the content of WPE in matrix asphalt was less than 10 wt%, the service performances of modified asphalt could be better.展开更多
In view of environmental and economic aspect, asphalt was modified with recycled packaging waste expended polystyrene (WEPS) instead of common polymer. The differential scanning calorimetry (DSC), rotational visco...In view of environmental and economic aspect, asphalt was modified with recycled packaging waste expended polystyrene (WEPS) instead of common polymer. The differential scanning calorimetry (DSC), rotational viscometer and dynamic shear rheology (DSR) were used to analyze and evaluate the viscoelasticity of modified asphalt. Results indicate that the sensitivity of modified asphalt to temperature is decreased while the rut resistance of asphalt is increased. In addition, the viscoelasticity of asphalt is improved after the modification with WEPS. Besides, the modified asphalt has high viscosity at low temperature and low viscosity at high temperature, which is favorable for construction.展开更多
Hydroxyapatite(HA)synthesized by a wet chemical route was subjected to heavy ion irradiation,using4 Me V Krypton ion(Kr17+)with ion fluence ranging from 1×1013 to 1×1015 ions/cm2.Glancing incidence X-ray dif...Hydroxyapatite(HA)synthesized by a wet chemical route was subjected to heavy ion irradiation,using4 Me V Krypton ion(Kr17+)with ion fluence ranging from 1×1013 to 1×1015 ions/cm2.Glancing incidence X-ray diffraction(GIXRD)results confirmed the phase purity of irradiated HA with a moderate contraction in lattice parameters,and further indicated the irradiation-induced structural disorder,evidenced by broadening of the diffraction peaks.High-resolution transmission electron microscopy(HRTEM)observations indicated that the applied Kr irradiation induced significant damage in the hydroxyapatite lattice.Specifically,cavities were observed with their diameter and density varying with the irradiation fluences,while a radiation-induced crystalline-to-amorphous transition with increasing ion dose was identified.Raman and X-ray photoelectron spectroscopy(XPS)analysis further indicated the presence of irradiationinduced defects.Ion release from pristine and irradiated materials following immersion in Tris(p H 7.4,37?)buffer showed that dissolution in vitro was enhanced by irradiation,reaching a peak at 0.1 dpa.We examined the effects of irradiation on the early stages of the mouse osteoblast-like cells(MC3 T3-E)response.A cell counting kit-8 assay(CCK-8 test)was carried out to investigate the cytotoxicity of samples,and viable cells can be observed on the irradiated materials.展开更多
基金This work was financially supported by the Science and Tech-nology Program of Shaanxi Province(No.2019GY-200).Shengwu Guo contributed to the material TEM characterization in this work.
文摘Hydrogen is a clean and flexible energy carrier that has the promising to satisfy urgent demands of the energy crisis and environmental protection.Electrochemical hydrogen evolution reaction(HER),a critical half-reaction in water splitting,is one of the greenest and most common methods to obtain high-purity hydrogen.Designing preeminent activity and stability electrocatalysts for hydrogen precipitation reac-tion(HER)to reduce energy consumption is of great essential.3D carbon-based materials have attracted widespread concern as the potential scaffolds of highly active and durable electrocatalysts for HER.To boost the HER activity and prolong the lifespan of electrocatalysts,multifarious 3D carbon architectures make an appearance to be engineered for accelerating electronic/mass transfer and maximizing the expo-sure of active sites.Herein,we designed and fabricated high-performance electrocatalysts based on a spe-cial caterpillar-like 3D graphene nanoscrolls@CNTs(GNS@CNTs)scaffold decorated with Co-doped MoSe_(2)nanosheets for HER.In the caterpillar-like hierarchical structure,CNTs were seamlessly co-bonded and dilated the interlayer and outer spacing of GNS through CVD growth technology,and nickel nanoparticles were covered by the CNTs tips.Taking advantage of the plentiful hierarchical pore,larger specific surface area,and higher chemical stability of the caterpillar-like structure,the catalysts exhibited enhanced elec-trocatalytic properties than some existing data reported.Density functional theory calculations showed that the encapsulated nickel nanoparticle could tune the electronic structure of the outer anchored Co-doped MoSe_(2)and optimize itsG of H∗adsorption by electron traversing effect and doping effect.These indicate that caterpillar-like GNS@CNT is an ideal scaffold f or anchoring actives substance and is suit-able for high-efficient HER.This study provides new insights for designing hierarchical carbon composite nanostructures for catalysts,sensors,energy materials,and other applications.
基金This work was supported by the Science and Technology Pro-gram of Shaanxi Province(No.2019GY-200).Shengwu Guo and Wei Wang contributed to the material TEM and SEM characterizations in this work.
文摘Attaining a highly efficient and inexpensive electrocatalyst is significant for the hydrogen evolution reaction(HER)but still challenging nowadays.The transition-metal phosphides(TMPs)catalysts with platinum-like electronic structures are a potential candidate for the HER,but those are prone to be strongly bound with hydrogen intermediates(H∗),resulting in sluggish HER kinetics.Herein we report a unique hybrid structure of CoP anchored on graphene nanoscrolls@carbon nano tubes(CNTs)scaffold(Ni M@C-CoP)encapsulating various Ni M(M=Zn,Mo,Ni,Co)bimetal nanoalloy via chemical vapor deposi-tion(CVD)growth of CNT on graphene nanoscrolls followed by the impregnation of cobalt precursors and phosphorization for efficiently electrocatalytic hydrogen evolution.CoP nanoparticles mainly scattered at the tip of CNT branches which exhibited the analogical“Three-layer core-shell”structures.Experiments and density functional theory(DFT)calculations consistently disclose that the encapsulated various NiMs can offer different numbers of electrons to weaken the interactions of outmost CoP with H∗and push the downshift of the d-band center to different degrees as well as stabilize the outmost CoP nanopar-ticles to gain catalytic stability via the electron traversing effect.The electrocatalytic HER activity can be maximumly enhanced with low overpotentials of 78 mV(alkaline)and 89 mV(acidic)at a current density of 10 mA/cm^(2) and sustained at least 24 h especially for NiZn@C-CoP catalyst.This novel system is distinct from conventional three-layer heterostructure,providing a specially thought of d-band center control engineering strategy for the design of heterogeneous catalysts and expanding to other electrocat-alysts,energy storage,sensing,and other applications.
基金financial support of the National Natural Science Foundation of China(32071327)National Key Research and Development Program of China(2016YFC1102003)+2 种基金International Science and Technology Cooperation Base of Shaanxi Province(2017GHJD-014)Science and Technology Program of Shaanxi Province(2019GY-200)Key Research and Development Program of Shaanxi Province(2019ZDLSF03-06)。
文摘The gradient porous Ti3Zr2Sn3Mo25Nb(TLM)alloy rods were fabricated through sintering the alloyed powder to a solid core.The porous sample was then modified by a Micro Arc Oxidation(MAO)treatment in an electrolyte containing calcium and phosphate,a hydrothermal treatment enabled secondary microporous hydroxyapatite(HA)coating,and a further bone morphogenetic protein-2(BMP-2)loading treatment through immersion and freeze-drying.The treatment led to an orderly secondary microporous coating containing HA nano-particles and evenly distributed BMP-2 in the porous coatings.As a result,osteoblasts could adhere and grow well on the coatings with a high cell adhesion rate and cell functional activity.The in-situ shear testing indicated that the interfacial strength had been enhanced significantly.Improvement of the bond formation and osseointegration with the titanium implant is attributed to increased surface area for the cell to attach,creating voids for the cell to grow in,and activating titanium surface by introducing bioactive ingredients such as HA and BMP-2.
基金support provided by the National Natural Science Foundation of China(Grant Nos. 51002118 and 51172180)Shaanxi Programs for Science and Technology Development(2011)+1 种基金Xi'an Programs for Industrial Applications(Grant No.CXY1129-3)the Beilin District Programs for Science and Technology Development(Grant No. GX1109)
文摘Waste polyethylene packaging (WPE) was used to modify asphalt, and hot storage stability of the modified asphalt was studied in this paper. The morphological change and component loss of WPE modified asphalt were characterized by fluorescence microscopy, Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetry (TG) and isolation testing. In addition, the mechanism of the hot storage stability of WPE modified asphalt was discussed. The results showed that the modification of asphalt with WPE was a physical process. It was found that the filament or partly network-like structure formed in the modified asphalt system was beneficial to improving the hot storage stability. Moreover, the addition of WPE resulted in a decrease in both the light components volatilization and the macromolecules decomposition of asphalt. It was demonstrated that when the content of WPE in matrix asphalt was less than 10 wt%, the service performances of modified asphalt could be better.
基金the financial support provided by the National Natural Science Foundation of China(Grant Nos.51002118,51172180)Program for New Century Excellent Talents in University of Ministry of Education of China(Grant No.NCET-12-1045)Shaanxi Programs for Outstanding Youth Project(2011)
文摘In view of environmental and economic aspect, asphalt was modified with recycled packaging waste expended polystyrene (WEPS) instead of common polymer. The differential scanning calorimetry (DSC), rotational viscometer and dynamic shear rheology (DSR) were used to analyze and evaluate the viscoelasticity of modified asphalt. Results indicate that the sensitivity of modified asphalt to temperature is decreased while the rut resistance of asphalt is increased. In addition, the viscoelasticity of asphalt is improved after the modification with WEPS. Besides, the modified asphalt has high viscosity at low temperature and low viscosity at high temperature, which is favorable for construction.
基金supported by the Science Challenge Project[No:TZ2018004]National Natural Science Foundation of China[Nos.51072159,51273159]+1 种基金Science and technology program of Shaanxi Province[No:2014K10-07]Technology Foundation for Selected Overseas Chinese Scholar,Department of Human Resources and Social Security of Shaanxi Province[No:2014-27].
文摘Hydroxyapatite(HA)synthesized by a wet chemical route was subjected to heavy ion irradiation,using4 Me V Krypton ion(Kr17+)with ion fluence ranging from 1×1013 to 1×1015 ions/cm2.Glancing incidence X-ray diffraction(GIXRD)results confirmed the phase purity of irradiated HA with a moderate contraction in lattice parameters,and further indicated the irradiation-induced structural disorder,evidenced by broadening of the diffraction peaks.High-resolution transmission electron microscopy(HRTEM)observations indicated that the applied Kr irradiation induced significant damage in the hydroxyapatite lattice.Specifically,cavities were observed with their diameter and density varying with the irradiation fluences,while a radiation-induced crystalline-to-amorphous transition with increasing ion dose was identified.Raman and X-ray photoelectron spectroscopy(XPS)analysis further indicated the presence of irradiationinduced defects.Ion release from pristine and irradiated materials following immersion in Tris(p H 7.4,37?)buffer showed that dissolution in vitro was enhanced by irradiation,reaching a peak at 0.1 dpa.We examined the effects of irradiation on the early stages of the mouse osteoblast-like cells(MC3 T3-E)response.A cell counting kit-8 assay(CCK-8 test)was carried out to investigate the cytotoxicity of samples,and viable cells can be observed on the irradiated materials.