Hydride ion(H-)conductors have drawn much attention due to their potential applications in hydrideion-based devices.Rare earth metal hydrides(REH_(x))have fast H-conduction which,unfortunately,is accompanied by detrim...Hydride ion(H-)conductors have drawn much attention due to their potential applications in hydrideion-based devices.Rare earth metal hydrides(REH_(x))have fast H-conduction which,unfortunately,is accompanied by detrimental electron conduction preventing their application as ion conductors.Here,REH_(x)(RE=Nd,Ce,and Pr)with varied grain sizes,rich grain boundaries,and defects have been prepared by ball milling and subsequent sintering.The electronic conductivity of the ball-milled REH_(x)samples can be reduced by 2-4 orders of magnitude compared with the non-ball-milled samples.The relationship of electron conduction and miscrostructures in REH_(x)is studied and discussed based on experimental data and previously-proposed classical and quantum theories.The H-conductivity of all REH_(x)is about 10^(-4)to 10^(-3)S cm^(-1)at room temperature,showing promise for the development of H-conductors and their applications in clean energy storage and conversion.展开更多
Connecting a triangle base and an apex forms a simplest polyhedron-that is,a tetrahedron.On account of their structural simplicity and stability,two common classes of tetrahedra-namely,M4L4 and M4L6 (M indicates anion...Connecting a triangle base and an apex forms a simplest polyhedron-that is,a tetrahedron.On account of their structural simplicity and stability,two common classes of tetrahedra-namely,M4L4 and M4L6 (M indicates anions or metal cations,L indicates ligands with C3 symmetry for M4L4 and C2 symmetry for M4L6,respectively)-can be readily constructed from (i) six straight edges through an edge-bridged strategy or (ii) four triangle faces through a face-capped strategy,by means of supramolecular or coordination assembly.The intrinsic cavities inside tetrahedra enable them to act as versatile hosts for encapsulating a variety of guests,which leads to a wide range of applications including molecular recognition,catalysis,sensing and so on.In this review,we intend to summarize specifically the work carried out in the realm of porous tetrahedral cages.It includes representative synthetic strategies for the preparation of tetrahedra along with a general summary on their structural features.Thereafter,we will highlight the state-of-the-art progress in various functions of tetrahedra,in addition to presenting a full overview of applications wherein we aim to provide new insights into the design and preparation of new topological geometric structures and functional materials on the basis of the simplest polyhedron-tetrahedron.展开更多
基金supported by the National Key Research and Development Program of China(2021YFB4000602)the National Natural Science Foundation of China(21988101,22279130,21633011)+1 种基金the Dalian Science and Technology Innovation Fund(2023RJ016)the Liaoning Revitalization Talents Program(x LYC2002076)。
文摘Hydride ion(H-)conductors have drawn much attention due to their potential applications in hydrideion-based devices.Rare earth metal hydrides(REH_(x))have fast H-conduction which,unfortunately,is accompanied by detrimental electron conduction preventing their application as ion conductors.Here,REH_(x)(RE=Nd,Ce,and Pr)with varied grain sizes,rich grain boundaries,and defects have been prepared by ball milling and subsequent sintering.The electronic conductivity of the ball-milled REH_(x)samples can be reduced by 2-4 orders of magnitude compared with the non-ball-milled samples.The relationship of electron conduction and miscrostructures in REH_(x)is studied and discussed based on experimental data and previously-proposed classical and quantum theories.The H-conductivity of all REH_(x)is about 10^(-4)to 10^(-3)S cm^(-1)at room temperature,showing promise for the development of H-conductors and their applications in clean energy storage and conversion.
文摘Connecting a triangle base and an apex forms a simplest polyhedron-that is,a tetrahedron.On account of their structural simplicity and stability,two common classes of tetrahedra-namely,M4L4 and M4L6 (M indicates anions or metal cations,L indicates ligands with C3 symmetry for M4L4 and C2 symmetry for M4L6,respectively)-can be readily constructed from (i) six straight edges through an edge-bridged strategy or (ii) four triangle faces through a face-capped strategy,by means of supramolecular or coordination assembly.The intrinsic cavities inside tetrahedra enable them to act as versatile hosts for encapsulating a variety of guests,which leads to a wide range of applications including molecular recognition,catalysis,sensing and so on.In this review,we intend to summarize specifically the work carried out in the realm of porous tetrahedral cages.It includes representative synthetic strategies for the preparation of tetrahedra along with a general summary on their structural features.Thereafter,we will highlight the state-of-the-art progress in various functions of tetrahedra,in addition to presenting a full overview of applications wherein we aim to provide new insights into the design and preparation of new topological geometric structures and functional materials on the basis of the simplest polyhedron-tetrahedron.
