In the endeavor of searching for highly active and stable electrocatalysts toward overall water splitting,high-entropy-alloys have been the intense subjects owing to their advanced physicochemical property.The non-nob...In the endeavor of searching for highly active and stable electrocatalysts toward overall water splitting,high-entropy-alloys have been the intense subjects owing to their advanced physicochemical property.The non-noble metal free-standing multiscale porous NiFeCoZn high-entropy-alloy is in situ constructed on the surface layer of NiZn intermetallic and Ni heterojunction over nickel foam(NiFeCoZn/NiZn-Ni/NF)by one scalable dealloying protocal to fulfill the outstanding bifunctional electrocatalytic performances toward overall water splitting.Because of the high-entropy effects and specific hierarchical porous architecture,the as-made NiFeCoZn/NiZn-Ni/NF displays high intrinsic catalytic activities and durability toward both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in alkaline media.In particular,the in-situ construction of bimodal porous NiFeCoZn high-entropy-alloy results in the small overpotentials(η1000=254/409 mV for HER and OER),low Tafel slopes,and exceptional long-term catalytic durability for 400 h.Expressively,the electrolyzer constructed with NiFeCoZn/NiZn-Ni/NF as both cathode and anode exhibits a low cell voltage of 1.72 V to deliver the current density of 500 mA·cm^(–2) for overall water splitting.This work not only provides a facile and scalable protocol for the preparation of self-supporting high-entropy-alloy nanocatalysts but also enlightens the engineering of high performance bifunctional electrocatalysts toward water splitting.展开更多
Proximal configu ration of dissimilar metal atoms in amorphous high-entropy-alloys(HEAs) always re sult in interatomic d-band ligand effect,dense defect distribution,coordinatively unsaturated sites,high potential ene...Proximal configu ration of dissimilar metal atoms in amorphous high-entropy-alloys(HEAs) always re sult in interatomic d-band ligand effect,dense defect distribution,coordinatively unsaturated sites,high potential energy,and loose atom bonding.Herein,nanostructured amorphous Fe_(29)Co_(27)Ni_(23)Si_(9)B_(12) HEA ribbon is fabricated via a melt spinning method combined with electrochemical corrosion etching process,which is applied as the potential oxygen evolution reaction electrocatalyst.It is found that there are micro/nano pits on the surface of etched amorphous Fe_(29)Co_(27)Ni_(23)Si_(9)B_(12) ribbons.Various elements of HEAs bond with each other to form a highly disordered configu ration,which could result in an optimized bonding energy and enhanced intrinsic catalytic activity.The electrocatalysis activity measurements indicate that the amorphous HEA endows a much higher activity than the crystalline one,which is further improved by the electrochemical etching treatment.Especially,the HEA ribbon etched for 3 h requires a low overpotential of 230 mV to afford 10 mA cm^(-2) current density.In addition,density functional theory calculations demonstrate that the amorphous structure can weaken the interaction between the surface of Fe_(29)Co_(27)Ni_(23)Si_(9)B_(12) alloy and the intermediates,leading to an optimized adsorption Gibbs free energy.展开更多
The effects of C element on the microstructure and properties of CoCrFeNiC,. high entropy alloys （x denoted the atomic fraction of C element at 0, 0.05, 0.1, 0.2, 0.3, and 0.5） were investigated. The equal molar CoC...The effects of C element on the microstructure and properties of CoCrFeNiC,. high entropy alloys （x denoted the atomic fraction of C element at 0, 0.05, 0.1, 0.2, 0.3, and 0.5） were investigated. The equal molar CoCrFeNi alloy with FCC structure exhibits high ductility but weak strength. With the addition of C element, both the hardness and strength of the CoCrFeNiCx high entropy alloys increase as well as the wear resistance. The solution strengthening and the lbrmation of hard carbide phase are the main thctor for the improved strength, hardness and wear resistance of CoCrFeNiC~ high entropy alloys.展开更多
Laser melting deposition with WC addition has been developed to fabricate high-strength CrMnFeCoNibased high-entropy alloys-based composites.By this technique,a microstructure of compact refined equiaxed grains can be...Laser melting deposition with WC addition has been developed to fabricate high-strength CrMnFeCoNibased high-entropy alloys-based composites.By this technique,a microstructure of compact refined equiaxed grains can be achieved,and the tensile strength can be remarkably improved.The sample with 5 wt%WC addition shows a promising mechanical performance with a tensile strength of 800 MPa and an elongation of 37%.The improvement in mechanical property may be attributed to the formation of Cr(23)C6 reinforcement precipitates,which could promote the heterogeneous nucleation of grains and hinder the propagation of slip bands.展开更多
在Q235钢基体上采用等离子弧熔覆法制备了Co Cr Cu Fe Mn Ni高熵合金涂层。采用SEM、EDS、XRD等研究了涂层的组织,利用显微硬度计测试了涂层的显微硬度分布。结果表明,采用等离子熔覆等摩尔Co、Cr、Cu、Fe、Mn、Ni单质金属混合粉,形成...在Q235钢基体上采用等离子弧熔覆法制备了Co Cr Cu Fe Mn Ni高熵合金涂层。采用SEM、EDS、XRD等研究了涂层的组织,利用显微硬度计测试了涂层的显微硬度分布。结果表明,采用等离子熔覆等摩尔Co、Cr、Cu、Fe、Mn、Ni单质金属混合粉,形成了无裂纹、无气孔缺陷,与基体冶金结合的高熵合金涂层。涂层厚度约为1 mm,主要由FCC1固溶体枝晶和少量枝晶间组织组成,枝晶间为BCC、FCC2相。涂层的显微硬度大约为260~390 HV0.2,明显高于基体的硬度（150~180 HV0.2）。展开更多
基金This work was financially supported by the National Natural Science Foundation of China(52201254)the Natural Science Foundation of Shandong Province(ZR2023ME155,ZR2020MB027)+1 种基金the project of“20 Items of University”of Jinan(202228046),and thee Taishan Scholar Project of Shandong Province(tsqn202306226)Southwest Medical University level research project(2022QN030).
文摘In the endeavor of searching for highly active and stable electrocatalysts toward overall water splitting,high-entropy-alloys have been the intense subjects owing to their advanced physicochemical property.The non-noble metal free-standing multiscale porous NiFeCoZn high-entropy-alloy is in situ constructed on the surface layer of NiZn intermetallic and Ni heterojunction over nickel foam(NiFeCoZn/NiZn-Ni/NF)by one scalable dealloying protocal to fulfill the outstanding bifunctional electrocatalytic performances toward overall water splitting.Because of the high-entropy effects and specific hierarchical porous architecture,the as-made NiFeCoZn/NiZn-Ni/NF displays high intrinsic catalytic activities and durability toward both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in alkaline media.In particular,the in-situ construction of bimodal porous NiFeCoZn high-entropy-alloy results in the small overpotentials(η1000=254/409 mV for HER and OER),low Tafel slopes,and exceptional long-term catalytic durability for 400 h.Expressively,the electrolyzer constructed with NiFeCoZn/NiZn-Ni/NF as both cathode and anode exhibits a low cell voltage of 1.72 V to deliver the current density of 500 mA·cm^(–2) for overall water splitting.This work not only provides a facile and scalable protocol for the preparation of self-supporting high-entropy-alloy nanocatalysts but also enlightens the engineering of high performance bifunctional electrocatalysts toward water splitting.
基金The financial supports from the key research&development and promotion of special project of Henan province (science&technology)(Grant No.192102210006)the Scientific Research Foundation of Zhengzhou University (32210862,32211241)。
文摘Proximal configu ration of dissimilar metal atoms in amorphous high-entropy-alloys(HEAs) always re sult in interatomic d-band ligand effect,dense defect distribution,coordinatively unsaturated sites,high potential energy,and loose atom bonding.Herein,nanostructured amorphous Fe_(29)Co_(27)Ni_(23)Si_(9)B_(12) HEA ribbon is fabricated via a melt spinning method combined with electrochemical corrosion etching process,which is applied as the potential oxygen evolution reaction electrocatalyst.It is found that there are micro/nano pits on the surface of etched amorphous Fe_(29)Co_(27)Ni_(23)Si_(9)B_(12) ribbons.Various elements of HEAs bond with each other to form a highly disordered configu ration,which could result in an optimized bonding energy and enhanced intrinsic catalytic activity.The electrocatalysis activity measurements indicate that the amorphous HEA endows a much higher activity than the crystalline one,which is further improved by the electrochemical etching treatment.Especially,the HEA ribbon etched for 3 h requires a low overpotential of 230 mV to afford 10 mA cm^(-2) current density.In addition,density functional theory calculations demonstrate that the amorphous structure can weaken the interaction between the surface of Fe_(29)Co_(27)Ni_(23)Si_(9)B_(12) alloy and the intermediates,leading to an optimized adsorption Gibbs free energy.
基金supported by the National Natural Science Foundation of China(Grant Nos.51471044 and 51671044)the Fundamental Research Funds for Central Universities,Key Laboratory of Basic Research Projects,Department of Education of Liaoning Province(Grant No.LZ2014007)the Natural Science Foundation of Liaoning Province(Grant No.2014028013)
文摘The effects of C element on the microstructure and properties of CoCrFeNiC,. high entropy alloys （x denoted the atomic fraction of C element at 0, 0.05, 0.1, 0.2, 0.3, and 0.5） were investigated. The equal molar CoCrFeNi alloy with FCC structure exhibits high ductility but weak strength. With the addition of C element, both the hardness and strength of the CoCrFeNiCx high entropy alloys increase as well as the wear resistance. The solution strengthening and the lbrmation of hard carbide phase are the main thctor for the improved strength, hardness and wear resistance of CoCrFeNiC~ high entropy alloys.
基金supported financially by the Project supported by CAEP Foundation (No.CX2019020)the Science and Technology Plan Project of Sichuan (No.2018G20146)the Special Fund Project of Panzhihua (No.2017CY-G-21)
文摘Laser melting deposition with WC addition has been developed to fabricate high-strength CrMnFeCoNibased high-entropy alloys-based composites.By this technique,a microstructure of compact refined equiaxed grains can be achieved,and the tensile strength can be remarkably improved.The sample with 5 wt%WC addition shows a promising mechanical performance with a tensile strength of 800 MPa and an elongation of 37%.The improvement in mechanical property may be attributed to the formation of Cr(23)C6 reinforcement precipitates,which could promote the heterogeneous nucleation of grains and hinder the propagation of slip bands.
文摘在Q235钢基体上采用等离子弧熔覆法制备了Co Cr Cu Fe Mn Ni高熵合金涂层。采用SEM、EDS、XRD等研究了涂层的组织,利用显微硬度计测试了涂层的显微硬度分布。结果表明,采用等离子熔覆等摩尔Co、Cr、Cu、Fe、Mn、Ni单质金属混合粉,形成了无裂纹、无气孔缺陷,与基体冶金结合的高熵合金涂层。涂层厚度约为1 mm,主要由FCC1固溶体枝晶和少量枝晶间组织组成,枝晶间为BCC、FCC2相。涂层的显微硬度大约为260~390 HV0.2,明显高于基体的硬度（150~180 HV0.2）。
