Due to the weak interlayer interactions,the binary Ⅲ-Ⅵ chalcogenides Ga Se can exist in several distinct polymorphs.Among them,the so-called β-and ε-phases simultaneously exhibit favorable total energies and moder...Due to the weak interlayer interactions,the binary Ⅲ-Ⅵ chalcogenides Ga Se can exist in several distinct polymorphs.Among them,the so-called β-and ε-phases simultaneously exhibit favorable total energies and moderate band gaps,which offer a good platform to explore their thermoelectric properties.Here,we demonstrate by first-principles calculations that the two systems have very similar band structures and phonon dispersions,despite different stacking sequences between adjacent layers.Interestingly,the lattice thermal conductivity of ε-GaSe is obviously lower than that of β-GaSe,which is inherently tied to stronger lattice anharmonicity caused by bonding heterogeneity.Besides,both systems exhibit higher p-type power factors due to doubly degenerate bands with weaker dispersions around the valence band maximum.As a consequence,a significantly enhanced p-type figure-of-merit of 2.1 can be realized at 700 K along the out-of-plane direction of theε-phase.展开更多
Organic templates provide structure for the frameworks of porous materials via a panel of weak and strong electrostatic interactions,i.e.,van der Waals forces,hydrogen bonds,and Coulomb interactions.The interactions b...Organic templates provide structure for the frameworks of porous materials via a panel of weak and strong electrostatic interactions,i.e.,van der Waals forces,hydrogen bonds,and Coulomb interactions.The interactions between the inorganic framework and the organic templates are not obvious,especially when there is no geometrical specificity between them.Then,one molecule may lead to different framework topologies,and similarly,a framework topology may be obtained with more than one template.In this work,we used two different templates,i.e.,triethylamine(TEA^(0))and tetraethylammonium(TEA^(+)),to synthesize aluminophosphate-five(AFI)zeotypes(AlPO-5 and SAPO-5)under microwave conditions.The syntheses were carried out using both molecules under identical experimental conditions,i.e.,with the same reagents,molar composition,crystallization time,and temperature.The structural and hydrophilic properties of the obtained materials were found to be highly dependent on the template used.A large set of characterization techniques was explored to understand short-and long-range order features.X-ray diffraction(XRD),scanning electron microscopy(SEM),inductively coupled plasma mass spectrometry(ICP-MS),energy dispersive X-ray(EDX)microanalysis,thermogravimetric analysis(TGA),nitrogen sorption,Fourier transform infrared(FT-IR)spectroscopy,and nuclear magnetic resonance(NMR)spectroscopy were used.Through these investigations,we elucidated the impact of templates on the synthesis process and the resulting properties.Our findings reveal that the templates served as space-filling agents,occupying the channels within the framework.Furthermore,the charge of the template exerted a significant influence on various aspects,including morphology,silicon content,and atomic-scale ordering.These modifications contributed to the enhancement of hydrophilicity in the AlPO-5 and SAPO-5 materials.This discovery provides a promising method for tailoring the properties of aluminophosphate-based water adsorbents in a straightforward manner.展开更多
A copper-based metal-organic framework(MOF)HKUST-1[Cu_(3)(BTC)2](H_(3)BTC=1,3,5-benzenetricarbocylic acid)was utilized as an artificial receptor to recognize a serine protease,α-chymotrypsin(ChT),with high affinity b...A copper-based metal-organic framework(MOF)HKUST-1[Cu_(3)(BTC)2](H_(3)BTC=1,3,5-benzenetricarbocylic acid)was utilized as an artificial receptor to recognize a serine protease,α-chymotrypsin(ChT),with high affinity by both electrostatic interactions and coordination interactions.The buffer molecule 4-(2-hydroxyethyl)-1-piperazinepropanesulfonic acid(HEPPS)could bind with copper(II)centers and form a negatively charged surface,leading to an electrostatic interaction between the cations on the surface of ChT.Meanwhile,according to Hard Soft Acid Base(HSAB)theory,the borderline Lewis acidic copper(II)centers could coordinate with the intermediate basic imidazole of His-57 at the active sites of ChT,preventing the binding of the substrate.Moreover,through coordination control by adding additional modulators,the different exposed facets with different arrangements of metal clusters and organic linkers could be obtained.Because the enzyme has different interactions with the metal centers and the organic linkers,the affinity between HKUST-1 and ChT could be well tuned.When more{111}facets than{100}facets existed in HKUST-1,the material exhibited better inhibition efficiency towards ChT.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.62074114 and 12474019)。
文摘Due to the weak interlayer interactions,the binary Ⅲ-Ⅵ chalcogenides Ga Se can exist in several distinct polymorphs.Among them,the so-called β-and ε-phases simultaneously exhibit favorable total energies and moderate band gaps,which offer a good platform to explore their thermoelectric properties.Here,we demonstrate by first-principles calculations that the two systems have very similar band structures and phonon dispersions,despite different stacking sequences between adjacent layers.Interestingly,the lattice thermal conductivity of ε-GaSe is obviously lower than that of β-GaSe,which is inherently tied to stronger lattice anharmonicity caused by bonding heterogeneity.Besides,both systems exhibit higher p-type power factors due to doubly degenerate bands with weaker dispersions around the valence band maximum.As a consequence,a significantly enhanced p-type figure-of-merit of 2.1 can be realized at 700 K along the out-of-plane direction of theε-phase.
基金funding from the Region of Normandy via the Label of Excellence for the Centre of Zeolites and Nanoporous Materials and Ministry of Education,France.Co-funding from the European Union(ERC,ZEOLIGHT,101054004)is acknowledged.
文摘Organic templates provide structure for the frameworks of porous materials via a panel of weak and strong electrostatic interactions,i.e.,van der Waals forces,hydrogen bonds,and Coulomb interactions.The interactions between the inorganic framework and the organic templates are not obvious,especially when there is no geometrical specificity between them.Then,one molecule may lead to different framework topologies,and similarly,a framework topology may be obtained with more than one template.In this work,we used two different templates,i.e.,triethylamine(TEA^(0))and tetraethylammonium(TEA^(+)),to synthesize aluminophosphate-five(AFI)zeotypes(AlPO-5 and SAPO-5)under microwave conditions.The syntheses were carried out using both molecules under identical experimental conditions,i.e.,with the same reagents,molar composition,crystallization time,and temperature.The structural and hydrophilic properties of the obtained materials were found to be highly dependent on the template used.A large set of characterization techniques was explored to understand short-and long-range order features.X-ray diffraction(XRD),scanning electron microscopy(SEM),inductively coupled plasma mass spectrometry(ICP-MS),energy dispersive X-ray(EDX)microanalysis,thermogravimetric analysis(TGA),nitrogen sorption,Fourier transform infrared(FT-IR)spectroscopy,and nuclear magnetic resonance(NMR)spectroscopy were used.Through these investigations,we elucidated the impact of templates on the synthesis process and the resulting properties.Our findings reveal that the templates served as space-filling agents,occupying the channels within the framework.Furthermore,the charge of the template exerted a significant influence on various aspects,including morphology,silicon content,and atomic-scale ordering.These modifications contributed to the enhancement of hydrophilicity in the AlPO-5 and SAPO-5 materials.This discovery provides a promising method for tailoring the properties of aluminophosphate-based water adsorbents in a straightforward manner.
基金supported the National Natural Science Foundation of China(NSFC Grant Numbers 21922407)the Young Elite Scholar Support(YESS)Program from CAST,the Program of Jiangsu Specially-Appointed Professor,the NSF of Jiangsu Province of China(No.BK20190086)the Innovation Team Program of Jiangsu Province of China,and the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘A copper-based metal-organic framework(MOF)HKUST-1[Cu_(3)(BTC)2](H_(3)BTC=1,3,5-benzenetricarbocylic acid)was utilized as an artificial receptor to recognize a serine protease,α-chymotrypsin(ChT),with high affinity by both electrostatic interactions and coordination interactions.The buffer molecule 4-(2-hydroxyethyl)-1-piperazinepropanesulfonic acid(HEPPS)could bind with copper(II)centers and form a negatively charged surface,leading to an electrostatic interaction between the cations on the surface of ChT.Meanwhile,according to Hard Soft Acid Base(HSAB)theory,the borderline Lewis acidic copper(II)centers could coordinate with the intermediate basic imidazole of His-57 at the active sites of ChT,preventing the binding of the substrate.Moreover,through coordination control by adding additional modulators,the different exposed facets with different arrangements of metal clusters and organic linkers could be obtained.Because the enzyme has different interactions with the metal centers and the organic linkers,the affinity between HKUST-1 and ChT could be well tuned.When more{111}facets than{100}facets existed in HKUST-1,the material exhibited better inhibition efficiency towards ChT.
