High-entropy alloys(HEAs)provide an ideal platform for developing highly active electrocatalysts and investigating the synergy of mixed elements.Far-from-equilibrium synthesis holds great potential for fabricating HEA...High-entropy alloys(HEAs)provide an ideal platform for developing highly active electrocatalysts and investigating the synergy of mixed elements.Far-from-equilibrium synthesis holds great potential for fabricating HEAs at the nanoscale by rapidly shifting the thermodynamic conditions and manipulat-ing the growth kinetics.While far-from-equilibrium synthesis of nanomaterials has been successful un-der thermochemical conditions,it is markedly challenging under electrochemical environments,as the use of an electrolyte limits the accessible temperature window and the temporal tunability of tem-perature.Herein,we demonstrate that applying a large electrochemical overpotential would create a far-from-equilibrium condition as changing the temperature of the system by considering the equation △G=△H−T△S+nF△ψ.An electrochemical far-from-equilibrium approach is thus setup for construct-ing hierarchical and self-supporting high-entropy alloy nanostructures.The large overpotential drives the simultaneous reduction of multiple cations and the subsequent formation of a single-phase alloy.As a proof-of-concept,hierarchical Fe_(0.22)Co_(0.18)Ni_(0.18)Cr_(0.14)Cu_(0.28)was fabricated and used as an electrocatalyst for the hydrogen evolution reaction in alkaline media.The noble-metal-free HEA exhibits an overpoten-tial of 84 mV at a current density of 10 mA cm^(-2),which is among the lowest even compared to noble metal-based electrocatalysts.This work opens a new avenue for building a variety of HEAs for energy and catalysis applications.展开更多
In the present work the Stochastic generalization of the quantum hydrodynamic analogy (SQHA) is used to obtain the far-from-equilibrium kinetics for a real gas and its fluid phase. In gases and their liquids, interact...In the present work the Stochastic generalization of the quantum hydrodynamic analogy (SQHA) is used to obtain the far-from-equilibrium kinetics for a real gas and its fluid phase. In gases and their liquids, interacting by Lennard-Jones potentials whose mean distance is bigger than the quantum correlation distance and the molecular interaction distance r0, it is possible to define a Fokker-Plank type equation of motion as a function of the mean phase space molecular volume that far-from-equilibrium shows maximizing the dissipation of a part of the generalized SQHA-free energy. In the case of a real gas with no chemical reactions with small temperature gradients, the principle disembogues into the maximum free energy dissipation confirming the experimental outputs of electro-convective instability. In this case, the model shows that the transition to stationary states with higher free energy can happen and that in incompressible fluids, the increase of free energy is almost given by a decrease of entropy leading to the appearance of self-ordered structures. The output of the theory showing that the generation of order via energy dissipation, is more efficient in fluids than in gases, because of their incompressibility, which leads to the reconciliation between physics and biology furnishing the explanation why the life was born in water. The theoretical output also suggests that the search for life out of the earth must consider the possibility to find it in presence of liquid phases different from water.展开更多
This paper presents not only practical but also instructive mathematical models to simulate tree network formation using the Poisson equation and the Finite Difference Method (FDM). Then, the implications for entropic...This paper presents not only practical but also instructive mathematical models to simulate tree network formation using the Poisson equation and the Finite Difference Method (FDM). Then, the implications for entropic theories are discussed from the viewpoint of Maximum Entropy Production (MEP). According to the MEP principle, open systems existing in the state far from equilibrium are stabilized when entropy production is maximized, creating dissipative structures with low entropy such as the tree-shaped network. We prepare two simulation models: one is the Poisson equation model that simulates the state far from equilibrium, and the other is the Laplace equation model that simulates the isolated state or the state near thermodynamic equilibrium. The output of these equations is considered to be positively correlated to entropy production of the system. Setting the Poisson equation model so that entropy production is maximized, tree network formation is advanced. We suppose that this is due to the invocation of the MEP principle, that is, entropy of the system is lowered by emitting maximal entropy out of the system. On the other hand, tree network formation is not observed in the Laplace equation model. Our simulation results will offer the persuasive evidence that certifies the effect of the MEP principle.展开更多
Angular correlation of excitation functions in dissipative heavy ion collision 27Al+27Al has been measured. The incident beam energies ranged from 114MeV to 127MeV in steps of 200keV. The angular analysis region was c...Angular correlation of excitation functions in dissipative heavy ion collision 27Al+27Al has been measured. The incident beam energies ranged from 114MeV to 127MeV in steps of 200keV. The angular analysis region was continuous from 50°to 90°in the center of mass system. An angular coherent width, at least 4n° was obtained. This long-range angular correlation could not be interpreted in the framework of the standard statistical reaction theory with state of equilibrium or near equilibrium, maybe it reveals the formation of a new kind of dissipative structure in the reaction of 27Al+27AI with the state that is far from equilibrium.展开更多
基金This work is supported by the China BaoWu Low Carbon Metallurgical Innovation Foundation-BWLCF202113The authors acknowledge the National Science Foundation of China(Nos.51971059,21903058,22173066,and 22103054)+1 种基金the Fundamen-tal Research Funds for the Central Universities(No.N2202012).T.C.thanks the support from Suzhou Key Laboratory of Functional Nano&Soft Materials,the Collaborative Innovation Center of Suzhou Nano Science&Technology,the Priority Academic Program Devel-opment of Jiangsu Higher Education Institutions(PAPD)the 111 Project.
文摘High-entropy alloys(HEAs)provide an ideal platform for developing highly active electrocatalysts and investigating the synergy of mixed elements.Far-from-equilibrium synthesis holds great potential for fabricating HEAs at the nanoscale by rapidly shifting the thermodynamic conditions and manipulat-ing the growth kinetics.While far-from-equilibrium synthesis of nanomaterials has been successful un-der thermochemical conditions,it is markedly challenging under electrochemical environments,as the use of an electrolyte limits the accessible temperature window and the temporal tunability of tem-perature.Herein,we demonstrate that applying a large electrochemical overpotential would create a far-from-equilibrium condition as changing the temperature of the system by considering the equation △G=△H−T△S+nF△ψ.An electrochemical far-from-equilibrium approach is thus setup for construct-ing hierarchical and self-supporting high-entropy alloy nanostructures.The large overpotential drives the simultaneous reduction of multiple cations and the subsequent formation of a single-phase alloy.As a proof-of-concept,hierarchical Fe_(0.22)Co_(0.18)Ni_(0.18)Cr_(0.14)Cu_(0.28)was fabricated and used as an electrocatalyst for the hydrogen evolution reaction in alkaline media.The noble-metal-free HEA exhibits an overpoten-tial of 84 mV at a current density of 10 mA cm^(-2),which is among the lowest even compared to noble metal-based electrocatalysts.This work opens a new avenue for building a variety of HEAs for energy and catalysis applications.
文摘In the present work the Stochastic generalization of the quantum hydrodynamic analogy (SQHA) is used to obtain the far-from-equilibrium kinetics for a real gas and its fluid phase. In gases and their liquids, interacting by Lennard-Jones potentials whose mean distance is bigger than the quantum correlation distance and the molecular interaction distance r0, it is possible to define a Fokker-Plank type equation of motion as a function of the mean phase space molecular volume that far-from-equilibrium shows maximizing the dissipation of a part of the generalized SQHA-free energy. In the case of a real gas with no chemical reactions with small temperature gradients, the principle disembogues into the maximum free energy dissipation confirming the experimental outputs of electro-convective instability. In this case, the model shows that the transition to stationary states with higher free energy can happen and that in incompressible fluids, the increase of free energy is almost given by a decrease of entropy leading to the appearance of self-ordered structures. The output of the theory showing that the generation of order via energy dissipation, is more efficient in fluids than in gases, because of their incompressibility, which leads to the reconciliation between physics and biology furnishing the explanation why the life was born in water. The theoretical output also suggests that the search for life out of the earth must consider the possibility to find it in presence of liquid phases different from water.
文摘This paper presents not only practical but also instructive mathematical models to simulate tree network formation using the Poisson equation and the Finite Difference Method (FDM). Then, the implications for entropic theories are discussed from the viewpoint of Maximum Entropy Production (MEP). According to the MEP principle, open systems existing in the state far from equilibrium are stabilized when entropy production is maximized, creating dissipative structures with low entropy such as the tree-shaped network. We prepare two simulation models: one is the Poisson equation model that simulates the state far from equilibrium, and the other is the Laplace equation model that simulates the isolated state or the state near thermodynamic equilibrium. The output of these equations is considered to be positively correlated to entropy production of the system. Setting the Poisson equation model so that entropy production is maximized, tree network formation is advanced. We suppose that this is due to the invocation of the MEP principle, that is, entropy of the system is lowered by emitting maximal entropy out of the system. On the other hand, tree network formation is not observed in the Laplace equation model. Our simulation results will offer the persuasive evidence that certifies the effect of the MEP principle.
基金the National Natural Science Foundation of China (No.19775057), the Chinese Academyof Sciences (KJ95T-03) and the Laboratoric
文摘Angular correlation of excitation functions in dissipative heavy ion collision 27Al+27Al has been measured. The incident beam energies ranged from 114MeV to 127MeV in steps of 200keV. The angular analysis region was continuous from 50°to 90°in the center of mass system. An angular coherent width, at least 4n° was obtained. This long-range angular correlation could not be interpreted in the framework of the standard statistical reaction theory with state of equilibrium or near equilibrium, maybe it reveals the formation of a new kind of dissipative structure in the reaction of 27Al+27AI with the state that is far from equilibrium.
