Silver selenide thin film is one of the best candidates for thermoelectric devices.In the previous report,we demonstrated that high-performanced[201]orientedβ-Ag_(2)Se thin films can be prepared by direct metal surfa...Silver selenide thin film is one of the best candidates for thermoelectric devices.In the previous report,we demonstrated that high-performanced[201]orientedβ-Ag_(2)Se thin films can be prepared by direct metal surface element reaction(DMSER)solution selenization in a really short time at room temperature.However,the underlying mechanism of the fast reaction process were not discussed in depth.Herein,based on hard soft acid base(HASB)theory and strong oxidation,we further explored the possible reaction mechanism of the in-situ growth ofβ-Ag_(2)Se thin films as the function of the reaction time.The time-dependent experimental results showed that the formation of theβ-Ag_(2)Se on elemental Ag precursor(∼690nm thick)in Se/Na_(2)S precursor solution is in a growth driven mode with no obvious orientation or growth rate selections to the elemental Ag precursors.Our investigations provide a prerequisite for the further preparation of thermoelectric materials with excellent properties.展开更多
Designing earth-abundant electrocatalysts with high performance towards water oxidation is highly decisive for the sustainable energy technologies. This study develops a facile natural corrosion approach to fabricate ...Designing earth-abundant electrocatalysts with high performance towards water oxidation is highly decisive for the sustainable energy technologies. This study develops a facile natural corrosion approach to fabricate nickel-iron hydroxides for water oxidation. The resulted electrode demonstrates an outstanding activity and stability with an overpotential of 275 mV to deliver 10 mA·cm^(−2). Experimental and theoretical results suggest the corrosion-induced formation of hydroxides and their transformation to oxyhydroxides would account for this excellent performance. This work not only provides an interesting corrosion approach for the fabrication of excellent water oxidation electrode, but also bridges traditional corrosion engineering and novel materials fabrication, which would offer some insights in the innovative principles for nanomaterials and energy technologies.展开更多
The evolution of microstructure and mechanical properties of Al-0.4 Cu-0.14 Si-0.05 Mg-0.2 Fe（wt.%）alloys, micro-alloyed with Zr, Ti and Sc, were investigated. The addition of 0.2%Zr to base alloy accelerates the pr...The evolution of microstructure and mechanical properties of Al-0.4 Cu-0.14 Si-0.05 Mg-0.2 Fe（wt.%）alloys, micro-alloyed with Zr, Ti and Sc, were investigated. The addition of 0.2%Zr to base alloy accelerates the precipitation of Si-rich nano-phase in α-Al matrix, which plays an important role in improving the mechanical properties of an alloy. The tensile strength increases from 102 MPa for the base alloy to 113 MPa for the Zr-modified alloy. Adding 0.2%Zr + 0.2%Ti to base alloy effectively refines a-Al grain size and accelerates the precipitation of Si and Cu elements, leading to heavy segregation at grain boundary.By further adding 0.2%Sc to Zr + Ti modified alloy, the segregation of Si and Cu elements is suppressed and more Si and Cu precipitates appeared in α-Al matrix. Accompanied with the formation of coherent Al;Sc phase, the tensile strength increases from 108 MPa for the Zr + Ti modified alloy to 152 MPa for the Sc-modified alloy. Due to excellent thermal stability of Al;Sc phase, the Sc-modified alloy exhibits obvious precipitation hardening behavior at 350℃, and the tensile strength increases to 203 MPa after holding at 350 ℃ for 200 h.展开更多
The P2-type manganese-based Na_(0.7)MnO_(2) cathode materials attract great interest due to their high theoretical capacity.However,these materials suffer from rapid capacity fading,poor rate performance and severe vo...The P2-type manganese-based Na_(0.7)MnO_(2) cathode materials attract great interest due to their high theoretical capacity.However,these materials suffer from rapid capacity fading,poor rate performance and severe voltage decay resulting from phase transition and sluggish reaction kinetics.In this work we report a novel Nb-doped Na_(0.7)[Ni_(0.3)Co_(0.1)Mn_(0.6)]_(1-x)Nb_(x)O_(2) with significantly suppre ssed voltage decay and enhanced cycling stability.The strong Nb-O bond can efficiently stabilize the TMO fra mework,and the as prepared material demonstrates much lower discharge midpoint voltage decay(0.132 V) than that of pristine one(0.319 V) after 200 cycles.Consequently,a remarkably improved cycling perfo rmance with a capacity retention of 87.9% after 200 cycle at 0.5 C is achieved,showing a 2.4 fold improvement as compared to the control sample Na_(0.7)Ni_(0.3)Co_(0.1)Mn_(0.6)O_(2)(~37% rotation).Even at 2 C,a capacity retention of 68.4% is retained after 500 cycles.Remarkably,the as prepared material can be applied at low temperature of-20℃,showing a capacity retention of 81% as compared to that at room temperature.展开更多
开发高效的铂(Pt)基电催化剂对于燃料电池的发展具有极其重要的意义.本文报道了一种氮掺杂纳米碳结构包覆的超低Pt合金集成电催化剂并用于燃料电池氧还原反应.该Pt基催化剂复合材料在0.9 V vs.RHE的电位下展现出3.46 A mg^(-1)_(Pt)质...开发高效的铂(Pt)基电催化剂对于燃料电池的发展具有极其重要的意义.本文报道了一种氮掺杂纳米碳结构包覆的超低Pt合金集成电催化剂并用于燃料电池氧还原反应.该Pt基催化剂复合材料在0.9 V vs.RHE的电位下展现出3.46 A mg^(-1)_(Pt)质量活性,并且在10000圈循环后几乎没有衰减.单电池测试结果表明,其Pt利用率高达10.22 W mg^(-1)_(Pt)阴极,并具有30000圈循环的优异耐久性.实验和理论研究表明,将Co/Ni掺入Pt晶格可产生具有最佳Pt-O结合能的高应变Pt结构,这可显著加快反应动力学.氮掺杂纳米碳结构和活性Pt组分产生的协同催化作用是提高催化活性的主要原因,同时增强的金属-载体相互作用和优化的亲水性能可促进传质过程和水管理.这项工作可为燃料电池及其他领域的低Pt集成电催化剂的设计提供重要见解.展开更多
基金the financial support provided by National Natural Science Foundation of China(Nos.52072327,21673200,21877027,61504117,U1604121)Zhongyuan Scholars Program of Henan Province,China(No.20210151004)+1 种基金Youth Talents Lifting Project of Henan Province,China(No.2018HYTP010)Key Research and Development Project of Henan Province,China(No.192102210183).
文摘Silver selenide thin film is one of the best candidates for thermoelectric devices.In the previous report,we demonstrated that high-performanced[201]orientedβ-Ag_(2)Se thin films can be prepared by direct metal surface element reaction(DMSER)solution selenization in a really short time at room temperature.However,the underlying mechanism of the fast reaction process were not discussed in depth.Herein,based on hard soft acid base(HASB)theory and strong oxidation,we further explored the possible reaction mechanism of the in-situ growth ofβ-Ag_(2)Se thin films as the function of the reaction time.The time-dependent experimental results showed that the formation of theβ-Ag_(2)Se on elemental Ag precursor(∼690nm thick)in Se/Na_(2)S precursor solution is in a growth driven mode with no obvious orientation or growth rate selections to the elemental Ag precursors.Our investigations provide a prerequisite for the further preparation of thermoelectric materials with excellent properties.
基金This work is financially supported by the National Natural Science Foundation of China(No.22075092)China Postdoctoral Science Foundation(No.2018M642810)the Program for HUST Academic Frontier Youth Team(No.2018QYTD15)。
文摘Designing earth-abundant electrocatalysts with high performance towards water oxidation is highly decisive for the sustainable energy technologies. This study develops a facile natural corrosion approach to fabricate nickel-iron hydroxides for water oxidation. The resulted electrode demonstrates an outstanding activity and stability with an overpotential of 275 mV to deliver 10 mA·cm^(−2). Experimental and theoretical results suggest the corrosion-induced formation of hydroxides and their transformation to oxyhydroxides would account for this excellent performance. This work not only provides an interesting corrosion approach for the fabrication of excellent water oxidation electrode, but also bridges traditional corrosion engineering and novel materials fabrication, which would offer some insights in the innovative principles for nanomaterials and energy technologies.
基金financial support of the project from the National Key Research and Development Project of China(No.2016YFB0301001,TC160A310-10)the Opening Fund of State Key Laboratory of Metal Matrix Composite(No.mmckdf16-03)Shanghai Jiao Tong University startup funding(No.13X100040023)
文摘The evolution of microstructure and mechanical properties of Al-0.4 Cu-0.14 Si-0.05 Mg-0.2 Fe（wt.%）alloys, micro-alloyed with Zr, Ti and Sc, were investigated. The addition of 0.2%Zr to base alloy accelerates the precipitation of Si-rich nano-phase in α-Al matrix, which plays an important role in improving the mechanical properties of an alloy. The tensile strength increases from 102 MPa for the base alloy to 113 MPa for the Zr-modified alloy. Adding 0.2%Zr + 0.2%Ti to base alloy effectively refines a-Al grain size and accelerates the precipitation of Si and Cu elements, leading to heavy segregation at grain boundary.By further adding 0.2%Sc to Zr + Ti modified alloy, the segregation of Si and Cu elements is suppressed and more Si and Cu precipitates appeared in α-Al matrix. Accompanied with the formation of coherent Al;Sc phase, the tensile strength increases from 108 MPa for the Zr + Ti modified alloy to 152 MPa for the Sc-modified alloy. Due to excellent thermal stability of Al;Sc phase, the Sc-modified alloy exhibits obvious precipitation hardening behavior at 350℃, and the tensile strength increases to 203 MPa after holding at 350 ℃ for 200 h.
基金supported by the National Natural Science Foundation of China (21673200, 61504117 and U1604121)the Innovation Scientists and Technicians Troop Construction Projects of Henan Province (144200510014)
基金the financial supports from the National Natural Science Foundation of China (No.51774251)Hebei Natural Science Foundation for Distinguished Young Scholars (No.B2017203313)+2 种基金Hundred Excellent Innovative Talents Support Program in Hebei Province (No.SLRC2017057)Talent Engineering Training Funds of Hebei Province (No.A201802001)the Opening Project of the State Key Laboratory of Advanced Chemical Power Sources (No. SKL-ACPS-C-11)。
文摘The P2-type manganese-based Na_(0.7)MnO_(2) cathode materials attract great interest due to their high theoretical capacity.However,these materials suffer from rapid capacity fading,poor rate performance and severe voltage decay resulting from phase transition and sluggish reaction kinetics.In this work we report a novel Nb-doped Na_(0.7)[Ni_(0.3)Co_(0.1)Mn_(0.6)]_(1-x)Nb_(x)O_(2) with significantly suppre ssed voltage decay and enhanced cycling stability.The strong Nb-O bond can efficiently stabilize the TMO fra mework,and the as prepared material demonstrates much lower discharge midpoint voltage decay(0.132 V) than that of pristine one(0.319 V) after 200 cycles.Consequently,a remarkably improved cycling perfo rmance with a capacity retention of 87.9% after 200 cycle at 0.5 C is achieved,showing a 2.4 fold improvement as compared to the control sample Na_(0.7)Ni_(0.3)Co_(0.1)Mn_(0.6)O_(2)(~37% rotation).Even at 2 C,a capacity retention of 68.4% is retained after 500 cycles.Remarkably,the as prepared material can be applied at low temperature of-20℃,showing a capacity retention of 81% as compared to that at room temperature.
基金the National Natural Science Foundation of China(22075092 and 21805104)the Program for Huazhong University of Science and Technology(HUST)Academic Frontier Youth Team(2018QYTD15)The Innovation and Talent Recruitment Base of New Energy Chemistry and Device(B21003)。
文摘开发高效的铂(Pt)基电催化剂对于燃料电池的发展具有极其重要的意义.本文报道了一种氮掺杂纳米碳结构包覆的超低Pt合金集成电催化剂并用于燃料电池氧还原反应.该Pt基催化剂复合材料在0.9 V vs.RHE的电位下展现出3.46 A mg^(-1)_(Pt)质量活性,并且在10000圈循环后几乎没有衰减.单电池测试结果表明,其Pt利用率高达10.22 W mg^(-1)_(Pt)阴极,并具有30000圈循环的优异耐久性.实验和理论研究表明,将Co/Ni掺入Pt晶格可产生具有最佳Pt-O结合能的高应变Pt结构,这可显著加快反应动力学.氮掺杂纳米碳结构和活性Pt组分产生的协同催化作用是提高催化活性的主要原因,同时增强的金属-载体相互作用和优化的亲水性能可促进传质过程和水管理.这项工作可为燃料电池及其他领域的低Pt集成电催化剂的设计提供重要见解.
