The effects of different solution methods on microstructure, mechanical properties and precipitation behavior of Al-Mg-Si alloy were investigated by scanning electron microscope, transmission electron microscope, tens...The effects of different solution methods on microstructure, mechanical properties and precipitation behavior of Al-Mg-Si alloy were investigated by scanning electron microscope, transmission electron microscope, tensile test, and differential scanning calorimetry. The results revealed that the recrystallized grains of the alloy after the solution treatment with hot air became smaller and more uniform, compared with solution treatment with electrical resistance. The texture of the alloy after two solution treatment methods was different. More rotated cube components were formed through solution treatment with electrical resistance, which was better for improving the drawability of the alloy. The strength of the alloy under the solution treatment with hot air was higher before stamping, because of the small uniform grains and many clusters in the matrix. The alloy solution treated with hot air also possessed good bake hardenability, because the transformation occurred on more clusters in the matrix.展开更多
Oxygen evolution reaction （OER） electrolysis, as an important reaction involved in water splitting and rechargeable metal-air batteries, has attracted increasing attention for clean energy generation and efficient e...Oxygen evolution reaction （OER） electrolysis, as an important reaction involved in water splitting and rechargeable metal-air batteries, has attracted increasing attention for clean energy generation and efficient energy storage. Nickel/iron （NiFe）-based compounds have been known as active OER catalysts since the last century, and renewed interest has been witnessed in recent years on developing advanced NiFe-based materials for better activity and stability. In this review, we present the early discovery and recent progress on NiFe-based OER electrocatalysts in terms of chemical properties, synthetic methodologies and catalytic performances. The advantages and disadvantages of each class of NiFe-based compounds are summarized, including NiFe alloys, electrodeposited films and layered double hydroxide nanoplates. Some mechanistic studies of the active phase of NiFe-based compounds are introduced and discussed to give insight into the nature of active catalytic sites, which could facilitate further improving NiFe based OER electrocatalysts. Finally, some applications of NiFe- based compounds for OER are described, including the development of an electrolyzer operating with a single AAA battery with voltage below 1.5 V and high performance rechargeable Zn-air batteries.展开更多
In this work,we demonstrated the enhanced oxygen evolution reaction（OER） activity of flower-shaped cobalt-nickel oxide（NiCo_2O_4） decorated with iridium-nickel bimetal as an electrode material.The samples were pre...In this work,we demonstrated the enhanced oxygen evolution reaction（OER） activity of flower-shaped cobalt-nickel oxide（NiCo_2O_4） decorated with iridium-nickel bimetal as an electrode material.The samples were prepared by carefully depositing pre-synthesized IrNi nanopartides on the surfaces of the NiCo_2O_4 nano-flowers.Compared with bare NiCo_2O_4,IrNi,and IrNi/Co_3O_4,the IrNi/NiCo_2O_4 exhibited significantly enhanced electrocatalytic activity in the OER,including a lower overpotential of 210 mV and a higher current density at an overpotential of 540 mV.We found that the IrNi/NiCo_2O_4 showed more efficient electron transport behavior and reduced polarization because of its bimetal IrNi modification by analyzing its Tafel slope and turnover frequency.Furthermore,the electrocatalytic mechanism of IrNi/NiCo_2O_4 in the OER was studied,and it was found that the combined active sites of the composite effectively improved the rate determining step.The synergic effect of the bimetal and metal oxide plays an important role in this reaction,enhancing the transmission efficiency of electrons and providing more active sites for the OER.The results reveal that IrNi/NiCo_2O_4 is an excellent electrocatalyst for OER.展开更多
基金Project(2016YFB0300605)supported by the National Key Research and Development Program of ChinaProject(51234002)supported by the National Natural Science Foundation of China+1 种基金Project(L2013113)supported by the Liaoning Province Science and Technology,ChinaProject(N140703002)supported by the Fundamental Research Funds for the Central Universities,China
文摘The effects of different solution methods on microstructure, mechanical properties and precipitation behavior of Al-Mg-Si alloy were investigated by scanning electron microscope, transmission electron microscope, tensile test, and differential scanning calorimetry. The results revealed that the recrystallized grains of the alloy after the solution treatment with hot air became smaller and more uniform, compared with solution treatment with electrical resistance. The texture of the alloy after two solution treatment methods was different. More rotated cube components were formed through solution treatment with electrical resistance, which was better for improving the drawability of the alloy. The strength of the alloy under the solution treatment with hot air was higher before stamping, because of the small uniform grains and many clusters in the matrix. The alloy solution treated with hot air also possessed good bake hardenability, because the transformation occurred on more clusters in the matrix.
文摘Oxygen evolution reaction （OER） electrolysis, as an important reaction involved in water splitting and rechargeable metal-air batteries, has attracted increasing attention for clean energy generation and efficient energy storage. Nickel/iron （NiFe）-based compounds have been known as active OER catalysts since the last century, and renewed interest has been witnessed in recent years on developing advanced NiFe-based materials for better activity and stability. In this review, we present the early discovery and recent progress on NiFe-based OER electrocatalysts in terms of chemical properties, synthetic methodologies and catalytic performances. The advantages and disadvantages of each class of NiFe-based compounds are summarized, including NiFe alloys, electrodeposited films and layered double hydroxide nanoplates. Some mechanistic studies of the active phase of NiFe-based compounds are introduced and discussed to give insight into the nature of active catalytic sites, which could facilitate further improving NiFe based OER electrocatalysts. Finally, some applications of NiFe- based compounds for OER are described, including the development of an electrolyzer operating with a single AAA battery with voltage below 1.5 V and high performance rechargeable Zn-air batteries.
基金supported by the National Natural Science Foundation of China(61371021 and 61671284)the support of Shanghai Education Commission(Peak Discipline Construction)
文摘In this work,we demonstrated the enhanced oxygen evolution reaction（OER） activity of flower-shaped cobalt-nickel oxide（NiCo_2O_4） decorated with iridium-nickel bimetal as an electrode material.The samples were prepared by carefully depositing pre-synthesized IrNi nanopartides on the surfaces of the NiCo_2O_4 nano-flowers.Compared with bare NiCo_2O_4,IrNi,and IrNi/Co_3O_4,the IrNi/NiCo_2O_4 exhibited significantly enhanced electrocatalytic activity in the OER,including a lower overpotential of 210 mV and a higher current density at an overpotential of 540 mV.We found that the IrNi/NiCo_2O_4 showed more efficient electron transport behavior and reduced polarization because of its bimetal IrNi modification by analyzing its Tafel slope and turnover frequency.Furthermore,the electrocatalytic mechanism of IrNi/NiCo_2O_4 in the OER was studied,and it was found that the combined active sites of the composite effectively improved the rate determining step.The synergic effect of the bimetal and metal oxide plays an important role in this reaction,enhancing the transmission efficiency of electrons and providing more active sites for the OER.The results reveal that IrNi/NiCo_2O_4 is an excellent electrocatalyst for OER.
