This work adopts a multi⁃step etching⁃heat treatment strategy to prepare porous silicon microsphere com⁃posite with Sb⁃Sn surface modification and carbon coating(pSi/Sb⁃Sn@C),using industrial grade SiAl alloy micro⁃sp...This work adopts a multi⁃step etching⁃heat treatment strategy to prepare porous silicon microsphere com⁃posite with Sb⁃Sn surface modification and carbon coating(pSi/Sb⁃Sn@C),using industrial grade SiAl alloy micro⁃spheres as a precursor.pSi/Sb⁃Sn@C had a 3D structure with bimetallic(Sb⁃Sn)modified porous silicon micro⁃spheres(pSi/Sb⁃Sn)as the core and carbon coating as the shell.Carbon shells can improve the electronic conductivi⁃ty and mechanical stability of porous silicon microspheres,which is beneficial for obtaining a stable solid electrolyte interface(SEI)film.The 3D porous core promotes the diffusion of lithium ions,increases the intercalation/delithia⁃tion active sites,and buffers the volume expansion during the intercalation process.The introduction of active met⁃als(Sb⁃Sn)can improve the conductivity of the composite and contribute to a certain amount of lithium storage ca⁃pacity.Due to its unique composition and microstructure,pSi/Sb⁃Sn@C showed a reversible capacity of 1247.4 mAh·g^(-1) after 300 charge/discharge cycles at a current density of 1.0 A·g^(-1),demonstrating excellent rate lithium storage performance and enhanced electrochemical cycling stability.展开更多
Different solvothermal reactions of ZnC2O_(4)with oxalic acid(H_(2)ox)and 1,2,4-triazole(Htrz)successfully gave a new quaternary(NJTU-Bai83,NJTU-Bai=Nanjing Tech University Bai's group)and a new quinary(NJTU-Bai84...Different solvothermal reactions of ZnC2O_(4)with oxalic acid(H_(2)ox)and 1,2,4-triazole(Htrz)successfully gave a new quaternary(NJTU-Bai83,NJTU-Bai=Nanjing Tech University Bai's group)and a new quinary(NJTU-Bai84)anionic metal-organic frameworks(MOFs),where NJTU-Bai83=(Me_(2)NH_(2))2[Zn_(3)(trz)_(2)(ox)_(3)]·2H_(2)O and NJTU-Bai84=(Me_(2)NH_(2))[Zn_(3)(trz)_(3)(ox)_(2)]·H_(2)O,respectively.With the[Zn_(2)(ox)4(trz)_(2)]secondary building unit(SBU)in NJTU-Bai83 replaced by the[Zn_(3)(ox)_(2)(trz)_(6)]and planar[Zn(ox)_(2)(trz)_(2)]ones in NJTU-Bai84,2D supramolecular building layers(SBLs)are changed from the A-layer and B-layer to another A-layer,while pillars are transformed from the tetrahedral[Zn(ox)_(2)(trz)_(2)]SBU to the irregular tetrahedral[Zn(ox)_(2)(trz)_(2)]and planar[Zn(ox)_(2)(trz)_(2)]SBUs.Thus,cdq-topological quaternary NJTU-Bai83 is tuned to(4,4,8)-c new topological quinary NJTU-Bai84.Two MOFs were well characterized by powder X-ray diffraction,thermogravimetric analysis,elemental analysis,etc.CCDC:2351819,NJTU-Bai83;2351820,NJTU-Bai84.展开更多
Structural uniformity is an important parameter influencing physical and mechanical properties of lotus-type porous metals prepared by directional solidification of metal-gas eutectic (Gasar). The effect of superheat ...Structural uniformity is an important parameter influencing physical and mechanical properties of lotus-type porous metals prepared by directional solidification of metal-gas eutectic (Gasar). The effect of superheat on structural uniformity as well as average porosity, pore morphology of porous metals was studied. The experimental results show that, when the superheat is higher than a critical value (ΔTc), the bubbling or boiling phenomenon will occur and the gas bubbles will form in the melt and float out of the melt. As a result, the final porosity will decrease. In addition, a higher superheat will simultaneously cause a non-uniform porous structure due to the pores coalescence and bubbling phenomenon. Finally, a theoretical model was developed to predict the critical superheat for the hydrogen to escape from the melt and the corresponding escapement ratio of hydrogen content. Considering the escapement of hydrogen, the predicted porosities are in good agreement with the experimental results.展开更多
The new chiral clusters [h5-C5H4C(NR)CH3]RuNiM(CO)5(m3-S) (R = NH-C6H3-2,4- (NO2)2, M = Mo, 3; M = W, 4) were synthesized and the structure of cluster 3 was determined by single-crystal X-ray analysis. Crystal data: C...The new chiral clusters [h5-C5H4C(NR)CH3]RuNiM(CO)5(m3-S) (R = NH-C6H3-2,4- (NO2)2, M = Mo, 3; M = W, 4) were synthesized and the structure of cluster 3 was determined by single-crystal X-ray analysis. Crystal data: C23H16O9N4MoNiRuS, Mr = 780.18, orthorhombic, space group Pbca with the following crystallographic parameters: a = 13.207(4), b = 16.036(5), c = 25.513(8) , Z = 8, V = 5403(3) 3, Dc = 1.918 g/cm3, m = 1.834 mm-1 and F(000) = 3072. The final R = 0.0512 and wR = 0.1132 for 2525 reflections with I > 2.00s(I).展开更多
A static and dynamic collaborative optimization method for materials and structure with uniform periodic microstructure is presented.The sensitivity formulae of hierarchical optimization,i.e.,material design,structure...A static and dynamic collaborative optimization method for materials and structure with uniform periodic microstructure is presented.The sensitivity formulae of hierarchical optimization,i.e.,material design,structure design and integrated design for porous metals,are given.On the base of the hierarchical optimization model,numerical experiments of an MBB beam and a cantilever one were carried out.Based on porous metals bearing multi-functionality,the differences and applicability of hierarchical optimization are discussed in the structure loading field.It is concluded that structure design is mainly oriented to structure efficiency,material design is mainly oriented to multi-functionality,and integrated design is oriented to structure efficiency and multi-functionality.This work provides some useful ideas for the selection of porous metals design method.展开更多
Rigid trigonal tris(3-pyridylduryl)borane L was synthesized through four steps in good overall yield from readily available 1,2,4,5-tetramethylbenzene and was used to construct two porous cadmium(II) complexes Cd(L)X2...Rigid trigonal tris(3-pyridylduryl)borane L was synthesized through four steps in good overall yield from readily available 1,2,4,5-tetramethylbenzene and was used to construct two porous cadmium(II) complexes Cd(L)X2.G(X = Cl,Br;G = guset molecules),1(Cd(L)Cl2.EtOH.iPrOH.3H2O) and 2(Cd(L)Br2.MeOH.C7H8.3H2O),under mild reaction conditions.1 and 2 are isostructural and featured with 3D porous metal-organoboron framewoks with rtl topology,in which L acts as a 3-connected node while a dicadmium motif serves as 6-connected node.In addition,1 and 2 exhibit strong photoluminescence in the visible region and 1 shows moderate adsorption ability of carbon dioxide at 273 K.展开更多
Porous metal architectures are widely adopted as three-dimensional conducting scaffolds for constructing Li metal composite anodes,whereas their macropores hinder their practical application due to limited surface are...Porous metal architectures are widely adopted as three-dimensional conducting scaffolds for constructing Li metal composite anodes,whereas their macropores hinder their practical application due to limited surface area and large pore size of few hundred micrometers.In this work,a network of Li_(x)Cu solid solution alloy nanowires is in situ formed via infiltrating molten Li-Cu alloy into Ni foam and subsequent cooling treatment,whereby a three-component composite anode consisting of Li metal,Li_(x)Cu alloy,and Ni foam is fabricated.The Li_(x)Cu nanowires nested as secondary frame split the macropores into micropores,enlarging the active surface area and inducing uniform Li deposition significantly.The lithiophilicity of the alloy wires and the shrunken void size built by the hierarchical architecture can further tune the nucleation and growth behavior of Li.The multiscale synergetic effect between the primary and secondary scaffold guarantees the composite anode sheet with extraordinarily long-term cycling stability even under high current rates.展开更多
Regulating metal surfaces with micro-/nanoscale structures is of great significance for both material science and potential applications.However,the intrinsic properties of metals,such as fixed isotropic moduli and in...Regulating metal surfaces with micro-/nanoscale structures is of great significance for both material science and potential applications.However,the intrinsic properties of metals,such as fixed isotropic moduli and inflexible structures,in a sense present major limitations in developing next-generation smart patterned surfaces.In this work,a facile and general patterning strategy is proposed to endow insensitive metal surfaces with controllable spontaneous topologies and dynamic performance by exquisitely introducing an essential photosensitive interlayer.The arresting anthracene-containing photocrosslinking interlayer can selectively predetermine the anisotropic property of compliant bilayers without damaging metals’homogeneous properties,and realize a changeable stiff/soft layer.Furthermore,the mechanical transition mechanism of the self-adaptive wrinkling modes in metalbased trilayer systems is revealed to pave the pathway for regulating functional wrinkled metal surfaces.This photodriven metal patterning strategy can promote the development of brand-new methods for tuning the instability of multilayered materials,and be potentially applied in smart optical devices with dynamic reflectance,including light gratings and"magic"mirrors.展开更多
Porous organic polymers(POPs) have recently emerged as promising candidates for catalyzing oxygen reduction reaction(ORR).Compared to conventional Pt-based ORR catalysts, these newly developed porous materials, includ...Porous organic polymers(POPs) have recently emerged as promising candidates for catalyzing oxygen reduction reaction(ORR).Compared to conventional Pt-based ORR catalysts, these newly developed porous materials, including both non-precious metal based catalysts and metal-free catalysts, are more sustainable and cost-effective. Their porous structures and large surface areas facilitate mass and electron transport and boost the ORR kinetics. This mini-review will give a brief summary of recent development of POPs as electrocatalysts for the ORR. Some design principles, different POP structures, key factors for their ORR catalytic performance, and outlook of POP materials will be discussed.展开更多
Noble metal-free and highly efficient electrocatalytic materials with hierarchically porous structures continue to be studied for the oxygen reduction reaction(ORR) in microbial fuel cells(MFCs). We report bimetal-org...Noble metal-free and highly efficient electrocatalytic materials with hierarchically porous structures continue to be studied for the oxygen reduction reaction(ORR) in microbial fuel cells(MFCs). We report bimetal-organic framework(bi-MOF)-derived nanocubic Swiss cheese-like carbons with a novel three-dimensional hierarchically porous structure(3D Co-N-C) prepared by utilizing cetyltrimethylammonium bromide(CTAB) as a structure-directing agent to control the formation of a nanocubic skeleton, and silica spheres as a template to form a mesoporous structure. The elemental composition and chemical morphology of this material can be tuned through the Zn/Co ratio to optimize its ORR catalytic activity. The optimized 3D Co-N-C displays excellent ORR catalytic performance(half-wave potential as high as 0.754 V vs. reversible hydrogen electrode and diffusion-limiting current density of 5.576 mA cm^(-2)) in 0.01 mol L^(-1) phosphate-buffered saline(PBS electrolyte),showing it can compete with the commercial 20 wt% Pt/C catalysts. The catalytic capability and long-term durability of 3D Co-N-C as an air-filled cathode electrocatalyst in an MFC device are tested, showing that the 3D CoNC-MFC can reach a high power density of 1257 mW m^(-2) and provide a competitive voltage during a periodic feeding operation for 192 h;these values are much higher than those of the Pt/C-MFC.展开更多
文摘This work adopts a multi⁃step etching⁃heat treatment strategy to prepare porous silicon microsphere com⁃posite with Sb⁃Sn surface modification and carbon coating(pSi/Sb⁃Sn@C),using industrial grade SiAl alloy micro⁃spheres as a precursor.pSi/Sb⁃Sn@C had a 3D structure with bimetallic(Sb⁃Sn)modified porous silicon micro⁃spheres(pSi/Sb⁃Sn)as the core and carbon coating as the shell.Carbon shells can improve the electronic conductivi⁃ty and mechanical stability of porous silicon microspheres,which is beneficial for obtaining a stable solid electrolyte interface(SEI)film.The 3D porous core promotes the diffusion of lithium ions,increases the intercalation/delithia⁃tion active sites,and buffers the volume expansion during the intercalation process.The introduction of active met⁃als(Sb⁃Sn)can improve the conductivity of the composite and contribute to a certain amount of lithium storage ca⁃pacity.Due to its unique composition and microstructure,pSi/Sb⁃Sn@C showed a reversible capacity of 1247.4 mAh·g^(-1) after 300 charge/discharge cycles at a current density of 1.0 A·g^(-1),demonstrating excellent rate lithium storage performance and enhanced electrochemical cycling stability.
文摘Different solvothermal reactions of ZnC2O_(4)with oxalic acid(H_(2)ox)and 1,2,4-triazole(Htrz)successfully gave a new quaternary(NJTU-Bai83,NJTU-Bai=Nanjing Tech University Bai's group)and a new quinary(NJTU-Bai84)anionic metal-organic frameworks(MOFs),where NJTU-Bai83=(Me_(2)NH_(2))2[Zn_(3)(trz)_(2)(ox)_(3)]·2H_(2)O and NJTU-Bai84=(Me_(2)NH_(2))[Zn_(3)(trz)_(3)(ox)_(2)]·H_(2)O,respectively.With the[Zn_(2)(ox)4(trz)_(2)]secondary building unit(SBU)in NJTU-Bai83 replaced by the[Zn_(3)(ox)_(2)(trz)_(6)]and planar[Zn(ox)_(2)(trz)_(2)]ones in NJTU-Bai84,2D supramolecular building layers(SBLs)are changed from the A-layer and B-layer to another A-layer,while pillars are transformed from the tetrahedral[Zn(ox)_(2)(trz)_(2)]SBU to the irregular tetrahedral[Zn(ox)_(2)(trz)_(2)]and planar[Zn(ox)_(2)(trz)_(2)]SBUs.Thus,cdq-topological quaternary NJTU-Bai83 is tuned to(4,4,8)-c new topological quinary NJTU-Bai84.Two MOFs were well characterized by powder X-ray diffraction,thermogravimetric analysis,elemental analysis,etc.CCDC:2351819,NJTU-Bai83;2351820,NJTU-Bai84.
基金Project(51271096)supported by the National Natural Science Foundation of ChinaProject(NCET-12-0310)supported by the Program for New Century Excellent Talents in University,Ministry of Education,China
文摘Structural uniformity is an important parameter influencing physical and mechanical properties of lotus-type porous metals prepared by directional solidification of metal-gas eutectic (Gasar). The effect of superheat on structural uniformity as well as average porosity, pore morphology of porous metals was studied. The experimental results show that, when the superheat is higher than a critical value (ΔTc), the bubbling or boiling phenomenon will occur and the gas bubbles will form in the melt and float out of the melt. As a result, the final porosity will decrease. In addition, a higher superheat will simultaneously cause a non-uniform porous structure due to the pores coalescence and bubbling phenomenon. Finally, a theoretical model was developed to predict the critical superheat for the hydrogen to escape from the melt and the corresponding escapement ratio of hydrogen content. Considering the escapement of hydrogen, the predicted porosities are in good agreement with the experimental results.
基金This work was supported by the National Natural Science Foundation of China
文摘The new chiral clusters [h5-C5H4C(NR)CH3]RuNiM(CO)5(m3-S) (R = NH-C6H3-2,4- (NO2)2, M = Mo, 3; M = W, 4) were synthesized and the structure of cluster 3 was determined by single-crystal X-ray analysis. Crystal data: C23H16O9N4MoNiRuS, Mr = 780.18, orthorhombic, space group Pbca with the following crystallographic parameters: a = 13.207(4), b = 16.036(5), c = 25.513(8) , Z = 8, V = 5403(3) 3, Dc = 1.918 g/cm3, m = 1.834 mm-1 and F(000) = 3072. The final R = 0.0512 and wR = 0.1132 for 2525 reflections with I > 2.00s(I).
基金supported by the National Basic Research Program of China ("973" Project) (Grant No. 2010CB832700)the Science and Technology Development Fundation of Academy of Engineering Physics(Grant No. 2008A0302011)
文摘A static and dynamic collaborative optimization method for materials and structure with uniform periodic microstructure is presented.The sensitivity formulae of hierarchical optimization,i.e.,material design,structure design and integrated design for porous metals,are given.On the base of the hierarchical optimization model,numerical experiments of an MBB beam and a cantilever one were carried out.Based on porous metals bearing multi-functionality,the differences and applicability of hierarchical optimization are discussed in the structure loading field.It is concluded that structure design is mainly oriented to structure efficiency,material design is mainly oriented to multi-functionality,and integrated design is oriented to structure efficiency and multi-functionality.This work provides some useful ideas for the selection of porous metals design method.
基金supported by the National Natural Foundation of China (21025103 & 20971085)the National Basic Research Program of China (2007CB209701 & 2009CB930403)+1 种基金Shanghai Science and Technology Committee(10DJ1400100)the Key Project of State Education Ministry
文摘Rigid trigonal tris(3-pyridylduryl)borane L was synthesized through four steps in good overall yield from readily available 1,2,4,5-tetramethylbenzene and was used to construct two porous cadmium(II) complexes Cd(L)X2.G(X = Cl,Br;G = guset molecules),1(Cd(L)Cl2.EtOH.iPrOH.3H2O) and 2(Cd(L)Br2.MeOH.C7H8.3H2O),under mild reaction conditions.1 and 2 are isostructural and featured with 3D porous metal-organoboron framewoks with rtl topology,in which L acts as a 3-connected node while a dicadmium motif serves as 6-connected node.In addition,1 and 2 exhibit strong photoluminescence in the visible region and 1 shows moderate adsorption ability of carbon dioxide at 273 K.
基金partly supported by the National Natural Science Foundation of China(21673033)Sichuan Science and Technology Program(2020071)the Fundamental Research Founds for the Central Universities(ZYGX2019J024).
文摘Porous metal architectures are widely adopted as three-dimensional conducting scaffolds for constructing Li metal composite anodes,whereas their macropores hinder their practical application due to limited surface area and large pore size of few hundred micrometers.In this work,a network of Li_(x)Cu solid solution alloy nanowires is in situ formed via infiltrating molten Li-Cu alloy into Ni foam and subsequent cooling treatment,whereby a three-component composite anode consisting of Li metal,Li_(x)Cu alloy,and Ni foam is fabricated.The Li_(x)Cu nanowires nested as secondary frame split the macropores into micropores,enlarging the active surface area and inducing uniform Li deposition significantly.The lithiophilicity of the alloy wires and the shrunken void size built by the hierarchical architecture can further tune the nucleation and growth behavior of Li.The multiscale synergetic effect between the primary and secondary scaffold guarantees the composite anode sheet with extraordinarily long-term cycling stability even under high current rates.
基金supported by the National Key R&D Program of China(2021YFB4001100)the National Natural Science Foundation of China(52025032,52103144,12032015,12121002,and 12172216)Science and Technology Innovation Action Plan of Shanghai(21190760100)。
文摘Regulating metal surfaces with micro-/nanoscale structures is of great significance for both material science and potential applications.However,the intrinsic properties of metals,such as fixed isotropic moduli and inflexible structures,in a sense present major limitations in developing next-generation smart patterned surfaces.In this work,a facile and general patterning strategy is proposed to endow insensitive metal surfaces with controllable spontaneous topologies and dynamic performance by exquisitely introducing an essential photosensitive interlayer.The arresting anthracene-containing photocrosslinking interlayer can selectively predetermine the anisotropic property of compliant bilayers without damaging metals’homogeneous properties,and realize a changeable stiff/soft layer.Furthermore,the mechanical transition mechanism of the self-adaptive wrinkling modes in metalbased trilayer systems is revealed to pave the pathway for regulating functional wrinkled metal surfaces.This photodriven metal patterning strategy can promote the development of brand-new methods for tuning the instability of multilayered materials,and be potentially applied in smart optical devices with dynamic reflectance,including light gratings and"magic"mirrors.
文摘Porous organic polymers(POPs) have recently emerged as promising candidates for catalyzing oxygen reduction reaction(ORR).Compared to conventional Pt-based ORR catalysts, these newly developed porous materials, including both non-precious metal based catalysts and metal-free catalysts, are more sustainable and cost-effective. Their porous structures and large surface areas facilitate mass and electron transport and boost the ORR kinetics. This mini-review will give a brief summary of recent development of POPs as electrocatalysts for the ORR. Some design principles, different POP structures, key factors for their ORR catalytic performance, and outlook of POP materials will be discussed.
基金supported by the National Natural Science Foundation of China (51976143)the National Key Research and Development Program of China (2018YFA0702001)Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory (XHD2020-002)。
文摘Noble metal-free and highly efficient electrocatalytic materials with hierarchically porous structures continue to be studied for the oxygen reduction reaction(ORR) in microbial fuel cells(MFCs). We report bimetal-organic framework(bi-MOF)-derived nanocubic Swiss cheese-like carbons with a novel three-dimensional hierarchically porous structure(3D Co-N-C) prepared by utilizing cetyltrimethylammonium bromide(CTAB) as a structure-directing agent to control the formation of a nanocubic skeleton, and silica spheres as a template to form a mesoporous structure. The elemental composition and chemical morphology of this material can be tuned through the Zn/Co ratio to optimize its ORR catalytic activity. The optimized 3D Co-N-C displays excellent ORR catalytic performance(half-wave potential as high as 0.754 V vs. reversible hydrogen electrode and diffusion-limiting current density of 5.576 mA cm^(-2)) in 0.01 mol L^(-1) phosphate-buffered saline(PBS electrolyte),showing it can compete with the commercial 20 wt% Pt/C catalysts. The catalytic capability and long-term durability of 3D Co-N-C as an air-filled cathode electrocatalyst in an MFC device are tested, showing that the 3D CoNC-MFC can reach a high power density of 1257 mW m^(-2) and provide a competitive voltage during a periodic feeding operation for 192 h;these values are much higher than those of the Pt/C-MFC.