Although platinum(Pt) is highly active for hydrogen evolution reaction(HER)[1], it is crucial to explore the effective approach for minimizing the Pt loading amount in the practical application. Herein, one ultralow-t...Although platinum(Pt) is highly active for hydrogen evolution reaction(HER)[1], it is crucial to explore the effective approach for minimizing the Pt loading amount in the practical application. Herein, one ultralow-temperature solution reduction approach is developed to anchor atomically dispersed Pt atoms on carbon nanotubes(Pt-CNTs), which decelerates the diffusion rate of Pt Cl2-6 ion reached onto the carbon nanotubes and lowers the free energy of Pt atoms in the solution to reduce the probability of the Pt aggregation. The obtained Pt-CNTs exhibits a low overpotential of 41 mV@10 mA cm^(-2) for HER in acidic media. The calculation results revealed that the improvement of the electrocatalytic activity is contributed by the interaction between CNTs and Pt atoms, which descreases the the Pt d band cneter referred to the Fermi level and lowers the Gibbs free energy of H*adsorption. This work may provide one easy and convenient strategy for the large-scale use of Pt catalysts in practical applications.展开更多
Magnesium(Mg)alloys are attractive biodegradable implant materials.The degradation products on Mg alloys play a critical role in the stability of the interface between implant and surrounding tissue.In the present stu...Magnesium(Mg)alloys are attractive biodegradable implant materials.The degradation products on Mg alloys play a critical role in the stability of the interface between implant and surrounding tissue.In the present study,the effects of dynamic deformation on the interface layer of biomedical Mg-1Zn alloy were investigated using the constant extension rate tensile tests(CERT)coupled with electrochemical impedance spectroscopy(EIS).The deformation of the Mg-1Zn alloy had an adverse influence on the impedance of the surface degradation layer formed in simulated body fluid that only containing inorganic compounds.However,the surface degradation layer with improved corrosion resistance was obtained for the strained samples tested in protein-containing simulated body fluid.The spontaneous or enhanced adsorption of protein into the degradation product led to a flexible and stable hybrid anti-corrosive layer.A relationship between the dynamic deformation of Mg alloy and the impendence of the degradation layer was established,which demonstrates the necessity for in situ characterisation of the evolution of the surface layer under dynamic condition.展开更多
The internal mechanisms of nucleation and growth of L1_(2)-AI_(3)RE(RE=Sc,Y,La-Lu) second phases in Al alloys were investigated by combining first-principles calculations with quasi-harmonic approximation(QHA).The cal...The internal mechanisms of nucleation and growth of L1_(2)-AI_(3)RE(RE=Sc,Y,La-Lu) second phases in Al alloys were investigated by combining first-principles calculations with quasi-harmonic approximation(QHA).The calculated results show that the diffusion rate D_s and chemical potential AG_V increase with the increase of temperature.With the increase of atomic number,the D_s and the strain energy ΔE_(CS)increase firstly from Sc to La,and then decreases,while the calculated interface energy γ_(α/β) and ΔG_V show opposite tendency.Based on above calculated results,the critical nucleation radius R*and coarsening rate K_(LSW) are obtained from the classical nucleation theory(CNT) and LSW model of the Ostwald ripening of particles,respectively.With the increase of atomic number,the R*increases firstly,and then decreases for all planes at finite temperatures.Whereas the K_(LSW) shows opposite variation to the R^(*).From this point of view,it is reasonably speculated that Y and later RE elements can replace the expensive Sc for heat-resistance Al alloys.The solubility c_(∞) of particles is usually very small at low temperature,and there is obvious solubility only when the temperature reaches 600 K.The surface energies E_(sur) of AI_(3)RE compounds and Al solid solution are respectively larger and smaller than that of pure Al,respectively,except for the surface(001) and(110) of Al_(3)La.For all planes,with the increase of atomic number of RE,E_(sur) decreases firstly from Sc to La,and then increases linearly to Lu.These results are helpful for designing high performance heat-resistance Al alloys.展开更多
A porous ceramic support is designed as a multi-functional independent catalyst layer for solid oxide fuel cells(SOFCs)running on liquid hydrocarbon fuel.The layer consists of a highly porous Ce_(0.9)Ca_(0.1)O_(2−δ)c...A porous ceramic support is designed as a multi-functional independent catalyst layer for solid oxide fuel cells(SOFCs)running on liquid hydrocarbon fuel.The layer consists of a highly porous Ce_(0.9)Ca_(0.1)O_(2−δ)ceramic backbone and active NiMo catalysts,which could be integrated into the conventional Ni metal containing the anode for internal reforming of the hydrocarbon fuel.Compared to conventional catalyst layers sintered on the anodes,this independent catalyst layer could be simply assembled on top of the anode without additional sintering,thereby avoiding the mismatch of the thermal expansion coefficient between the catalyst layer and the anode and improving stability of a single cell.Moreover,a current collector layer could be inserted between the catalyst and the anode to enhance current collection efficiency and electrochemical performance of the single cell.At 750℃,the independent catalyst layer displays high activity towards the catalytic decomposition of methanol,and the single cell could achieve the maximum power density of 400–500 mW·cm^(−2)in dry methanol.Furthermore,by employing the independent catalyst layer,the single cell offers additional in-situ catalyst regeneration capability under the methanol operation mode.Feeding 10 mL·min−1 air into an anode channel for 5 min is found to be effective to burn out carbon species in the catalyst layer,which reduces the degradation rate of the cell voltage by orders of magnitude from 2.6 to 0.024 mV·h−1 during the operation of 360 h in dry methanol.The results demonstrate the significance of the independent catalyst layer design for direct internal reforming methanol fuel cells.展开更多
To overcome the dimension limits of immiscible alloys produced by traditional techniques and enhance their mechanical properties,bulk Cu-Fe-based immiscible alloy with abundant nanotwins and stacking faults was succes...To overcome the dimension limits of immiscible alloys produced by traditional techniques and enhance their mechanical properties,bulk Cu-Fe-based immiscible alloy with abundant nanotwins and stacking faults was successfully produced by selective laser melting(SLM).The SLM-produced bulk immiscible alloy displays a heterogeneous microstructure characterized by micro-scaledγ-Fe particles dispersed in fineε-Cu matrix with a high fraction(~92%)of high-angle grain boundaries.Interestingly,abundant nanotwins and stacking faults are generated in the interior of nano-scaledγ-Fe particles embedded withinε-Cu matrix.The heterogeneous interface of soft domains(ε-Cu)and hard domains(γ-Fe)not only induces the geometrically necessary dislocations(GNDs)but also affects the dislocation propagation during plastic deformation.Therefore,the bimodal heterogeneous interface,and the resistance of nanotwins and stacking faults to the propagation of partial dislocation make the bulk immiscible alloy exhibit an enhanced strength of~590 MPa and a good ductility of~8.9%.展开更多
In this work,lithium(Li)-aluminum(Al)layered double hydroxide(LDH)films modified by 4-amino-2-((hydrazine methylene)amino)-4-oxobutanoic acid(denoted as AOA acid)and/or 1H,1H,2H,2H-perfluorooctyltriethoxysilane were p...In this work,lithium(Li)-aluminum(Al)layered double hydroxide(LDH)films modified by 4-amino-2-((hydrazine methylene)amino)-4-oxobutanoic acid(denoted as AOA acid)and/or 1H,1H,2H,2H-perfluorooctyltriethoxysilane were prepared on 6N01 Al alloy by a facile,in-situ growth method with enhanced hydrophobicity,anti-biofouling and anti-corrosion performance.The preparation is low energy consumptive and environment friendly,relying on self-assembly at ambient temperature.The structure,molecular weight and functional groups of the synthesized AOA acid were characterized by NMR spectrometer,ESI-MS spectrometer and Fourier transform infrared(FT-IR)spectroscopy.And the compositions,structure and morphology of the films were characterized by Fourier transform infrared(FT-IR)spectroscopy,glancing-angle X-ray diffraction(GA-XRD),X-ray photoelectron spectroscopy(XPS),field emission scanning electron microscopy(FE-SEM)and energy-dispersive x-ray spectrum(EDS).Water contact angle measurements(CA)and atomic force microscopy(AFM)characterization show that the films possess a micro/nanostructure with an improved hydrophobicity.Immersion test,neutral salt tests(NSS)and electrochemical impedance spectroscopy(EIS)conducted in 3.5 wt.%NaCl solutions demonstrate the improved corrosion resistance of the films over bare Al alloy.Meanwhile,the films also possess an excellent anti-bacterial property toEscherichia coli,Bacillus subtilis and sulfate-reducing bacteria.展开更多
CeO_(2)/g-C_(3)N_(4)photocatalysts have attracted tremendous attention in the photocatalytic degradation of organic pollutants.The design and construction of highly active CeO_(2)/g-C_(3)N_(4)photocatalysts without ha...CeO_(2)/g-C_(3)N_(4)photocatalysts have attracted tremendous attention in the photocatalytic degradation of organic pollutants.The design and construction of highly active CeO_(2)/g-C_(3)N_(4)photocatalysts without harsh conditions are still challenging.Herein,highly dispersed CeO_(2-x)nanoparticles with rich oxygen vacancies were successfully precipitated on the surface of g-C_(3)N_(4)under mild conditions.The fabricated CeO_(2-x)/g-C_(3)N_(4)exhibits remarkable activity and stability for photocatalytic degradation of MO pollutant.The optimal rate constant of MO degradation over CeO_(2-x)/g-C_(3)N_(4)is about 0.031 min^(-1),which is three times higher than that of g-C_(3)N_(4).A negligible activity decrease is observed after three cycling runs.The enhanced catalytic performance can be ascribed to the excellent dispersion of CeO_(2-x)with rich oxygen vacancies that benefit O_(2)adsorption and visible light absorption.In addition,the proper band alignment between CeO_(2-x)and gC_(3)N_(4)is conducive to the highly efficient separation of photogenerated electron-hole pairs.展开更多
基金financial support from the National Natural Science Foundation of China (No. 51572183)the Key Research and Development Plan of Science and Technology of China (No. 2018YFE0202600)。
文摘Although platinum(Pt) is highly active for hydrogen evolution reaction(HER)[1], it is crucial to explore the effective approach for minimizing the Pt loading amount in the practical application. Herein, one ultralow-temperature solution reduction approach is developed to anchor atomically dispersed Pt atoms on carbon nanotubes(Pt-CNTs), which decelerates the diffusion rate of Pt Cl2-6 ion reached onto the carbon nanotubes and lowers the free energy of Pt atoms in the solution to reduce the probability of the Pt aggregation. The obtained Pt-CNTs exhibits a low overpotential of 41 mV@10 mA cm^(-2) for HER in acidic media. The calculation results revealed that the improvement of the electrocatalytic activity is contributed by the interaction between CNTs and Pt atoms, which descreases the the Pt d band cneter referred to the Fermi level and lowers the Gibbs free energy of H*adsorption. This work may provide one easy and convenient strategy for the large-scale use of Pt catalysts in practical applications.
基金supported by National Key R&D Program of China(2017YFB0305100,2017YFB0305104)the Science and Technology Planning Project of Guangdong Province No.2017B090903005+2 种基金the financial support from Jinan University(No.21620110)the financial support from Science and Technology Planning Project of Guangdong Province(No.2021A0505030042)the financial support from Guangdong Basic and Applied Basic Research Foundation(2019A1515110580)。
文摘Magnesium(Mg)alloys are attractive biodegradable implant materials.The degradation products on Mg alloys play a critical role in the stability of the interface between implant and surrounding tissue.In the present study,the effects of dynamic deformation on the interface layer of biomedical Mg-1Zn alloy were investigated using the constant extension rate tensile tests(CERT)coupled with electrochemical impedance spectroscopy(EIS).The deformation of the Mg-1Zn alloy had an adverse influence on the impedance of the surface degradation layer formed in simulated body fluid that only containing inorganic compounds.However,the surface degradation layer with improved corrosion resistance was obtained for the strained samples tested in protein-containing simulated body fluid.The spontaneous or enhanced adsorption of protein into the degradation product led to a flexible and stable hybrid anti-corrosive layer.A relationship between the dynamic deformation of Mg alloy and the impendence of the degradation layer was established,which demonstrates the necessity for in situ characterisation of the evolution of the surface layer under dynamic condition.
基金Project supported by the R&D plan for Key Areas in Guangdong Province (2020B010186001)the National Natural Science Foundation of China (52171115,52071299)。
文摘The internal mechanisms of nucleation and growth of L1_(2)-AI_(3)RE(RE=Sc,Y,La-Lu) second phases in Al alloys were investigated by combining first-principles calculations with quasi-harmonic approximation(QHA).The calculated results show that the diffusion rate D_s and chemical potential AG_V increase with the increase of temperature.With the increase of atomic number,the D_s and the strain energy ΔE_(CS)increase firstly from Sc to La,and then decreases,while the calculated interface energy γ_(α/β) and ΔG_V show opposite tendency.Based on above calculated results,the critical nucleation radius R*and coarsening rate K_(LSW) are obtained from the classical nucleation theory(CNT) and LSW model of the Ostwald ripening of particles,respectively.With the increase of atomic number,the R*increases firstly,and then decreases for all planes at finite temperatures.Whereas the K_(LSW) shows opposite variation to the R^(*).From this point of view,it is reasonably speculated that Y and later RE elements can replace the expensive Sc for heat-resistance Al alloys.The solubility c_(∞) of particles is usually very small at low temperature,and there is obvious solubility only when the temperature reaches 600 K.The surface energies E_(sur) of AI_(3)RE compounds and Al solid solution are respectively larger and smaller than that of pure Al,respectively,except for the surface(001) and(110) of Al_(3)La.For all planes,with the increase of atomic number of RE,E_(sur) decreases firstly from Sc to La,and then increases linearly to Lu.These results are helpful for designing high performance heat-resistance Al alloys.
基金support from the National Natural Science Foundation of China(No.22005051)Guangdong Basic and Applied Basic Research Foundation(Nos.2019A1515110237 and 2022A1515012001)+3 种基金Young Creative Talents Project of the Guangdong Provincial Department of Education(No.2019KQNCX166)Innovation Research Project of University in Foshan City(No.2020XCC09).Grateful acknowledgements are extended to the National Natural Science Foundation of China(No.51872047)Key Project Plat Form Programs and Technology Innovation Team Project of Guangdong Provincial Department of Education(Nos.2019KZDXM039,2019GCZX002,and 2020KCXTD011)Guangdong Provincial Key Research and Development Plan(No.2020B090920001)。
文摘A porous ceramic support is designed as a multi-functional independent catalyst layer for solid oxide fuel cells(SOFCs)running on liquid hydrocarbon fuel.The layer consists of a highly porous Ce_(0.9)Ca_(0.1)O_(2−δ)ceramic backbone and active NiMo catalysts,which could be integrated into the conventional Ni metal containing the anode for internal reforming of the hydrocarbon fuel.Compared to conventional catalyst layers sintered on the anodes,this independent catalyst layer could be simply assembled on top of the anode without additional sintering,thereby avoiding the mismatch of the thermal expansion coefficient between the catalyst layer and the anode and improving stability of a single cell.Moreover,a current collector layer could be inserted between the catalyst and the anode to enhance current collection efficiency and electrochemical performance of the single cell.At 750℃,the independent catalyst layer displays high activity towards the catalytic decomposition of methanol,and the single cell could achieve the maximum power density of 400–500 mW·cm^(−2)in dry methanol.Furthermore,by employing the independent catalyst layer,the single cell offers additional in-situ catalyst regeneration capability under the methanol operation mode.Feeding 10 mL·min−1 air into an anode channel for 5 min is found to be effective to burn out carbon species in the catalyst layer,which reduces the degradation rate of the cell voltage by orders of magnitude from 2.6 to 0.024 mV·h−1 during the operation of 360 h in dry methanol.The results demonstrate the significance of the independent catalyst layer design for direct internal reforming methanol fuel cells.
基金financially supported by the Projects of MOE Key Lab of Disaster Forecast and Control in Engineering in Jinan University(No.20200904006)the Guangdong Basic and Applied Basic Research Foundation(No.2020B1515420004)。
文摘To overcome the dimension limits of immiscible alloys produced by traditional techniques and enhance their mechanical properties,bulk Cu-Fe-based immiscible alloy with abundant nanotwins and stacking faults was successfully produced by selective laser melting(SLM).The SLM-produced bulk immiscible alloy displays a heterogeneous microstructure characterized by micro-scaledγ-Fe particles dispersed in fineε-Cu matrix with a high fraction(~92%)of high-angle grain boundaries.Interestingly,abundant nanotwins and stacking faults are generated in the interior of nano-scaledγ-Fe particles embedded withinε-Cu matrix.The heterogeneous interface of soft domains(ε-Cu)and hard domains(γ-Fe)not only induces the geometrically necessary dislocations(GNDs)but also affects the dislocation propagation during plastic deformation.Therefore,the bimodal heterogeneous interface,and the resistance of nanotwins and stacking faults to the propagation of partial dislocation make the bulk immiscible alloy exhibit an enhanced strength of~590 MPa and a good ductility of~8.9%.
基金The work was financially supported by the National Natural Science Foundation of China(No.51871097)China Scholarship Council(No.201906130085)+7 种基金the National Natural Science Foundation of Hunan Province,China(No.2019JJ40033)the Key-Area Research and Development Program of Guangdong Province,China(No.2020B010186001)the Major Special Foundation of Research and Innovation of Qiannan Normal University for Nationalities,China(No.QNSY2018XK005)the Construction Project of Novel Catalysis Materials Development and Engineering Research Center for Guizhou General College(Guizhou“KY”[2015]342)Guangzhou Goal and Energy Conservation Tech.Co.Ltd.China Petroleum and Chemical CorporationSinopec Beijing Research Institute of Chemical Industrythe University of Calgary。
文摘In this work,lithium(Li)-aluminum(Al)layered double hydroxide(LDH)films modified by 4-amino-2-((hydrazine methylene)amino)-4-oxobutanoic acid(denoted as AOA acid)and/or 1H,1H,2H,2H-perfluorooctyltriethoxysilane were prepared on 6N01 Al alloy by a facile,in-situ growth method with enhanced hydrophobicity,anti-biofouling and anti-corrosion performance.The preparation is low energy consumptive and environment friendly,relying on self-assembly at ambient temperature.The structure,molecular weight and functional groups of the synthesized AOA acid were characterized by NMR spectrometer,ESI-MS spectrometer and Fourier transform infrared(FT-IR)spectroscopy.And the compositions,structure and morphology of the films were characterized by Fourier transform infrared(FT-IR)spectroscopy,glancing-angle X-ray diffraction(GA-XRD),X-ray photoelectron spectroscopy(XPS),field emission scanning electron microscopy(FE-SEM)and energy-dispersive x-ray spectrum(EDS).Water contact angle measurements(CA)and atomic force microscopy(AFM)characterization show that the films possess a micro/nanostructure with an improved hydrophobicity.Immersion test,neutral salt tests(NSS)and electrochemical impedance spectroscopy(EIS)conducted in 3.5 wt.%NaCl solutions demonstrate the improved corrosion resistance of the films over bare Al alloy.Meanwhile,the films also possess an excellent anti-bacterial property toEscherichia coli,Bacillus subtilis and sulfate-reducing bacteria.
基金financially supported by the National Natural Science Foundation of China (22008032 and 22078104)Guangdong Basic and Applied Basic Research Foundation (2019A1515110706)+6 种基金Guangdong Natural Science Foundation (2017A030313052 and 2019A1515011121)the Key Project of Department of Education of Guangdong Province (2016GCZX008)the National Key Research and Development Program (2019YFC1805804)the Innovation Team of Universities in Guangdong Province (2020KCXTD011)the Engineering Research Center of Universities in Guangdong Province (2019GCZX002)the Guangdong Key Laboratory for Hydrogen Energy Technologies (2018B030322005)the Fundamental Research Funds for the Central Universities
基金Project supported by the Guangdong Provincial Education Department Special Project of Key Research Areas(2020ZDZX2066)the Innovation Team of Universities of Guangdong Province(2020KCXTD011)+2 种基金the Engineering Research Center of Universities of Guangdong Province(2019GCZX002)the Guangdong Key Laboratory for Hydrogen Energy Technologies(2018B030322005)Guangdong Basic and Applied Basic Research Foundation(2019A1515110586,2019A1515110534)。
文摘CeO_(2)/g-C_(3)N_(4)photocatalysts have attracted tremendous attention in the photocatalytic degradation of organic pollutants.The design and construction of highly active CeO_(2)/g-C_(3)N_(4)photocatalysts without harsh conditions are still challenging.Herein,highly dispersed CeO_(2-x)nanoparticles with rich oxygen vacancies were successfully precipitated on the surface of g-C_(3)N_(4)under mild conditions.The fabricated CeO_(2-x)/g-C_(3)N_(4)exhibits remarkable activity and stability for photocatalytic degradation of MO pollutant.The optimal rate constant of MO degradation over CeO_(2-x)/g-C_(3)N_(4)is about 0.031 min^(-1),which is three times higher than that of g-C_(3)N_(4).A negligible activity decrease is observed after three cycling runs.The enhanced catalytic performance can be ascribed to the excellent dispersion of CeO_(2-x)with rich oxygen vacancies that benefit O_(2)adsorption and visible light absorption.In addition,the proper band alignment between CeO_(2-x)and gC_(3)N_(4)is conducive to the highly efficient separation of photogenerated electron-hole pairs.