A novel micro-micro/mesoporous aluminosilicate ZSM-5-Y/MCM-41 composite molecular sieve with a MCM-41 type structure was synthesized through a novel process of the self-assembly of CTAB surfactant micellae with silica...A novel micro-micro/mesoporous aluminosilicate ZSM-5-Y/MCM-41 composite molecular sieve with a MCM-41 type structure was synthesized through a novel process of the self-assembly of CTAB surfactant micellae with silica-alumina source originated from alkaline treatment of ZSM-5 zeolite.The physical properties of the ZSM-5- Y/MCM-41 composite molecular sieve were characterized by XRD,Py-FTIR and N_2 adsorption-desorption techniques. Different kinds of molecular sieves including ZSM-5,Y zeolite,Al-MCM-41,ZSM-5/MCM-41 and ZSM-5-Y/MCM- 41 as cracking catalysts were investigated,using 1,3,5-triisopropylbenzene(1,3,5-TIPB) as the probe molecule.Catalytic tests showed that the ZSM-5-Y/MCM-41 composite molecular sieve exhibited higher catalytic activity compared with the microporous ZSM-5 zeolite,Y zeolite,mesoporous Al-MCM-41 molecular sieve and ZSM-5/MCM-41 composite molecular sieve under the same conditions.The remarkable catalytic activity was mainly attributed to the presence of the hierarchical pore structure and proper acidity in the ZSM-5-Y/MCM-41 composite catalyst.Meanwhile, a carbenium ion mechanism was put forward for the cracking of 1,3,5-TIPB.展开更多
Perovskite-type mixed protonic-electronic conducting membranes have attracted attention because of their ability to separate and purify hydrogen from a mixture of gases generated by industrial-scale steam reforming ba...Perovskite-type mixed protonic-electronic conducting membranes have attracted attention because of their ability to separate and purify hydrogen from a mixture of gases generated by industrial-scale steam reforming based on an ion diffusion mechanism.Exploring cost-effective membrane materials that can achieve both high H_(2) permeability and strong CO_(2)-tolerant chemical stability has been a major challenge for industrial applications.Herein,we constructed a triple phase(ceramic-metal-ceramic)membrane composed of a perovskite ceramic phase BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ)(BZCYYb),Ni metal phase and a fluorite ceramic phase CeO_(2).Under H_(2) atmosphere,Ni metal in-situ exsolved from the oxide grains,and decorated the grain surface and boundary,thus the electronic conductivity and hydrogen separation performance can be promoted.The BZCYYbNi-CeO_(2)hybrid membrane achieved an exceptional hydrogen separation performance of 0.53 mL min^(-1)cm^(-2) at 800℃ under a 10 vol% H_(2) atmosphere,surpassing all other perovskite membranes reported to date.Furthermore,the CeO_(2) phase incorporated into the BZCYYb-Ni effectively improved the CO_(2)-tolerant chemical stability.The BZCYYbNi-CeO_(2) membrane exhibited outstanding long-term stability for at least 80 h at 700℃ under 10 vol%CO_(2)-10 vol%H_(2).The success of hybrid membrane construction creates a new direction for simultaneously improving their hydrogen separation performance and CO_(2) resistance stability.展开更多
Electrochemical carbon dioxide(CO_(2))reduction(ECR)is a promising technology to produce valuable fuels and feedstocks from CO_(2).Despite large efforts to develop ECR catalysts,the investigation of the catalytic perf...Electrochemical carbon dioxide(CO_(2))reduction(ECR)is a promising technology to produce valuable fuels and feedstocks from CO_(2).Despite large efforts to develop ECR catalysts,the investigation of the catalytic performance and electrochemical behavior of complex metal oxides,especially perovskite oxides,is rarely reported.Here,the inorganic perovskite oxide Ag-doped(La_(0.8)Sr_(0.2))_(0.95)Ag_(0.05)MnO_(3-δ)(LSA0.05M)is reported as an efficient electrocatalyst for ECR to CO for the first time,which exhibits a Faradaic efficiency(FE)of 84.3%,a remarkable mass activity of 75Ag^(-1)(normalized to the mass of Ag),and stability of 130 h at a moderate overpotential of 0.79 V.The LSA0.05M catalyst experiences structure reconstruction during ECR,creating the in operando-formed interface between the perovskite and the evolved Ag phase.The evolved Ag is uniformly distributed with a small particle size on the perovskite surface.Theoretical calculations indicate the reconstruction of LSA0.05M during ECR and reveal that the perovskite-Ag interface provides adsorption sites for CO_(2) and accelerates the desorption of the*CO intermediate to enhance ECR.This study presents a novel high-performance perovskite catalyst for ECR andmay inspire the future design of electrocatalysts via the in operando formation of metal-metal oxide interfaces.展开更多
Recently, giant intrinsic anomalous Hall effect(AHE) has been observed in the materials with kagome lattice.Here, we systematically investigate the influence of high pressure on the AHE in the ferromagnet LiMn_(6)Sn_(...Recently, giant intrinsic anomalous Hall effect(AHE) has been observed in the materials with kagome lattice.Here, we systematically investigate the influence of high pressure on the AHE in the ferromagnet LiMn_(6)Sn_(6) with clean Mn kagome lattice. Our in situ high-pressure Raman spectroscopy indicates that the crystal structure of LiMn_(6)Sn_(6) maintains a hexagonal phase under high pressures up to 8.51 GPa. The anomalous Hall conductivity(AHC) σ_(xy)^(A) remains around 150 Ω^(-1)·cm^(-1), dominated by the intrinsic mechanism. Combined with theoretical calculations, our results indicate that the stable AHE under pressure in Li Mn_(6)Sn_(6) originates from the robust electronic and magnetic structure.展开更多
Controlling collective electronic states hold great promise for development of innovative devices. Here, we experimentally detect the modification of the charge density wave(CDW) phase transition within a 1T-TaS_(2) l...Controlling collective electronic states hold great promise for development of innovative devices. Here, we experimentally detect the modification of the charge density wave(CDW) phase transition within a 1T-TaS_(2) layer in a WS_(2)/1T-TaS_(2) heterostructure using time-resolved ultrafast spectroscopy. Laser-induced charge transfer doping strongly suppresses the commensurate CDW phase, which results in a significant decrease in both the phase transition temperature(T_(c)) and phase transition stiffness. We interpret the phenomenon that photoinduced hole doping, when surpassing a critical threshold value of ~ 10^(18)cm^(-3), sharply decreases the phase transition energy barrier. Our results provide new insights into controlling the CDW phase transition, paving the way for optical-controlled novel devices based on CDW materials.展开更多
A novel flower-like hydrated magnesium carbonate hydroxide, Mg5 (CO3 )4 (OH)2·4H2O, with micro-structure composed of individual thin nano-sheets was synthesized using a facile solution route without the use o...A novel flower-like hydrated magnesium carbonate hydroxide, Mg5 (CO3 )4 (OH)2·4H2O, with micro-structure composed of individual thin nano-sheets was synthesized using a facile solution route without the use of template or organic surfactant. Reaction time has an important effect on the final morphology of the product. The micro-structure and morphology of Mg5 (CO3)4 (OH)2·4H2O were characterized by means of X-ray diffractometry (XRD), fieldemission scanning electron microscopy(FE-SEM). Brunauer-Emmett-Teller(BET) surface areas of the samples were also measured. The probable formation mechanism of flower-like micro-structure was discussed. It was found that Mg5 (CO3)4( OH)2·4H2O with flower-like micro-structure was a novel and efficient catalyst for the synthesis of diphenyl carbonate (DPC) by transesterification of dimethyl carbonate (DMC) with phenol.展开更多
2H-MoS_(2) is a well-studied and promising non-noble metal electrocatalyst for heterogeneous reactions,such as the hydrogen evolution reaction(HER).The performance is largely limited by the chemically inert basal plan...2H-MoS_(2) is a well-studied and promising non-noble metal electrocatalyst for heterogeneous reactions,such as the hydrogen evolution reaction(HER).The performance is largely limited by the chemically inert basal plane,which is unfavorable for surface adsorption and reactions.Herein,we report a facile method to boost the HER activities of 2H-MoS_(2) by coupling with epitaxial Bi2Te3 topological insulator films.The as-obtained MoS_(2)/Bi2Te3/SrTiO3 catalyst exhibits prominent HER catalytic activities compared to that of pure MoS_(2) structures,with a 189 mV decrease in the overpotential required to reach a current density of 10 mA cm^(−2) and a low Tafel slope of 58 mV dec−1.Theoretical investigations suggest that the enhanced catalytic activity originates from the charge redistribution at the interface between the Bi2Te3topological insulator films and the MoS_(2) layer.The delocalized sp-derived topological surface states could denote electrons to the MoS_(2) layer and activate the basal plane for hydrogen adsorption.This study demonstrates the potential of manipulating topological surface states to design high-performance electrocatalysts.展开更多
Superhydrophobic surface was prepared on the zinc substrate by chemical solution method via immersing clean pure zinc substrate into a water solution of zinc nitrate hexahydrate[Zn(NO3)2.6H2O] and hexamethylenete- t...Superhydrophobic surface was prepared on the zinc substrate by chemical solution method via immersing clean pure zinc substrate into a water solution of zinc nitrate hexahydrate[Zn(NO3)2.6H2O] and hexamethylenete- traamine(C6H12N4) at 95 ℃ in water bath for 1.5 h, then modified with 18 alkanethiol. The best resulting surface shows superhydrophobic properties with a water contact angle of about 158° and a low water roll-off angle of around 3°. The prepared samples were characterized by powder X-ray diffraction(XRD), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy(EDX), transmission electron microscopy(TEM), and scanning electron microscopy(SEM). SEM images of the films show that the resulting surface exhibits flower-shaped micro- and nano-structure. The surfaces of the prepared films were composed of ZnO nanorods which were wurtzite structure. The special flower-like micro- and nano-structure along with the low surface energy leads to the surface superhydro- phobicity.展开更多
Photocatalytic water splitting has emerged as a new frontier for converting solar energy to green H_(2) and value-added chemicals.Nevertheless,great challenges still remain for developing efficient photocatalysts for ...Photocatalytic water splitting has emerged as a new frontier for converting solar energy to green H_(2) and value-added chemicals.Nevertheless,great challenges still remain for developing efficient photocatalysts for pure water splitting without sacrificial agents.In this work,we demonstrate that doping hexagonal ZnIn_(2)S_(4)(ZIS) with Pd single atoms(Pd_(0.03)/ZIS) can serve as a highly efficient photocatalyst for pure water splitting to simultaneously produce H_(2) and H_(2)O_(2) without any sacrificial agents.Results from aberration-corrected high-angle annular dark field scanning transmission electron microscopy,X-ray fine spectroscopy,insitu electron paramagnetic resonance and diffuse Fourier transform infrared spectroscopy reveal that doping ZIS with Pd single atoms facilitates the formation of S vacancies(S_(v)),where the photogenerated electrons can transfer to Pd single atoms,as a result of enhanced separation of electron-hole pairs and improved photocatalytic performance.Impressively,Pd_(0.03)/ZIS displays a stoichiometric ratio of H_(2) and H_(2)O_(2) with the productivity of 1,037.9 and 1,021.4μmol g^(-1)h^(-1),respectively,which has largely outperformed pure ZIS and other reported catalysts for pure water splitting.This work provides an efficient photocatalyst for water splitting to produce H_(2) and H_(2)O_(2),which may attract rapid interest in materials science,chemistry,and heterogeneous catalysis.展开更多
The one-pot synthesis of dimethyl carbonate(DMC) with co-production of propy-lene carbonate(PC) and propylene glycol(PG) from propylene oxide( PO), carbon dioxide and methanol as the starting materials was inv...The one-pot synthesis of dimethyl carbonate(DMC) with co-production of propy-lene carbonate(PC) and propylene glycol(PG) from propylene oxide( PO), carbon dioxide and methanol as the starting materials was investigated. The catalyst adopted here was a mixture of tetrabutyl ammonium bromide and sodium methoxide. It was found that un- der the reaction conditions of t = 150 ℃, p =3-4 MPa and 2 h, the PO conversion could reach 100%, the DMC, PC and the PG selectivities were 49. 7%, 42. 7% and 49. 8%, respectively, and the selectivity of by-products was below 10%.展开更多
A new three-dimensional supramolecule composed of copper-Schiff base complex, [Cu(naphdien)]Cl·H2O, where naphdien is Schiff base of 2-hydroxy-1-naphthaldehyde and diethylenetriamine, has been synthesized and d...A new three-dimensional supramolecule composed of copper-Schiff base complex, [Cu(naphdien)]Cl·H2O, where naphdien is Schiff base of 2-hydroxy-1-naphthaldehyde and diethylenetriamine, has been synthesized and determined by single-crystal X-ray diffraction. It belongs to the monoclinic system, space group P21/c, with a = 7.3490(15), b = 7.0847(16), c = 30.845(3)A, β= 95.33(3)°, V = 1599.0(5)A3, Z = 4, C15 H20ClCuN3O2, Mr = 373.33, De = 1.551 g/cm3, μ = 1.543 mm^-1, F(000) = 772, R = 0.0536 and wR = 0.0927 for 2788 unique reflections with 1659 observed ones (I 〉2σ(I)). In the crystal structure, mononuclear units [Cu(naphdien)]Cl·H2O are linked into a two-dimensional framework via strong hydrogen bonds, and extended into a three-dimensional supramolecular structure through π-π stacking interactions.展开更多
The hierarchically structured ZSM-5 monolith was prepared through transforming the skeletons of the macroporous silica gel into ZSM-5 by the steam-assisted conversion method. The morphology and monolithic shapes of ma...The hierarchically structured ZSM-5 monolith was prepared through transforming the skeletons of the macroporous silica gel into ZSM-5 by the steam-assisted conversion method. The morphology and monolithic shapes of macroporous silica gel were well preserved. The hierarchically structured ZSM-5 monolith exhibited the hierarchical porosity, with mesopores and macropores existing inside the macroporous silica gel, and micropores formed by the ZSM-5. The products have been characterized properly by using the XRD, SEM and N2 adsorption–desorption methods.展开更多
The polyoxometalate-imidazole ionic liquids(POM-ILs) with low melting points at 94.5 and 95.5 ℃, [Cn mim]a[MosO26](Cn mim=1-alkyl-3-methylimidazolium, n=12,14), have been successfully synthesized and characterize...The polyoxometalate-imidazole ionic liquids(POM-ILs) with low melting points at 94.5 and 95.5 ℃, [Cn mim]a[MosO26](Cn mim=1-alkyl-3-methylimidazolium, n=12,14), have been successfully synthesized and characterized by DSC, single-crystal X-ray diffraction and TGA, etc. The two POM-ILs have relatively high stability with decomposing temperature up to about 347 and 344 ℃, respectively. Further photocatalytic performance was measured via the degradation of rhodamine B(RB) in aqueous solution. The experiments show that the conversion reached to 90% after 90 min under UV-light and the degradation efficiency depended on pH value, different dosages and so on. In addition, the catalysts can be recycled for several times without significant loss of activity.展开更多
Iron-based superconductor family FeX(X=S,Se,Te)has been one of the research foci in physics and material science due to their record-breaking superconducting temperature(FeSe film)and rich physical phenomena.Recently,...Iron-based superconductor family FeX(X=S,Se,Te)has been one of the research foci in physics and material science due to their record-breaking superconducting temperature(FeSe film)and rich physical phenomena.Recently,FeS,the least studied Fe X compound(due to the difficulty in synthesizing high quality macroscopic crystals)attracted much attention because of its puzzling superconducting pairing symmetry.In this work,combining scanning tunneling microscopy and angle resolved photoemission spectroscopy(ARPES)with sub-micron spatial resolution,we investigate the intrinsic electronic structures of superconducting FeS from individual single crystalline domains.Unlike FeTe or FeSe,FeS remains identical tetragonal structure from room temperature down to 5 K,and the band structures observed can be well reproduced by our ab-initio calculations.Remarkably,mixed with the 1×1 tetragonal metallic phase,we also observe the coexistence of √5×√5 reconstructed insulating phase in the crystal,which not only helps explain the unusual properties of FeS,but also demonstrates the importance of using spatially resolved experimental tools in the study of this compound.展开更多
The title complex {[AgL]ClO4}n(L=2,5-bis(3-pyridinylmethylthio)-1,3,4-thiadiazole) was synthesized by the reaction of Ag(I) salt and a novel flexible ligand L.Its structure was determined by X-ray crystallograph...The title complex {[AgL]ClO4}n(L=2,5-bis(3-pyridinylmethylthio)-1,3,4-thiadiazole) was synthesized by the reaction of Ag(I) salt and a novel flexible ligand L.Its structure was determined by X-ray crystallography with the following data:monoclinic,space group P21/n,a=16.5068(13),b=7.6548(4),c=16.5521(13)A,β=115.119(3)o,V=1893.7(2)A^3,Z=4,Dc=1.893 g/cm^3,μ=1.565 mm^-1,F(000)=1072,C14H12AgClN4O4S3,Mr=539.78,T=293(2) K,S=1.067,the final R=0.0342 and wR=0.0870.The silver ion in the complex is in a trigonal coordination geometry to link three different L.Meanwhile,each L connects three different silver ions by its N coordination sites to form a two-dimensional layer structure.展开更多
The polyoxometalate(POM)-imidazole ionic liquid(IL) [C8mim]2[Mo6O19](C8mim=1-methyl-3-octylimi- dazolium) with a low melting point of 82.6 °C was successfully prepared and characterized by FTIR, XPS, NMR, T...The polyoxometalate(POM)-imidazole ionic liquid(IL) [C8mim]2[Mo6O19](C8mim=1-methyl-3-octylimi- dazolium) with a low melting point of 82.6 °C was successfully prepared and characterized by FTIR, XPS, NMR, TG and so on. The polyoxomolybdate-based IL has high stability, and its decomposing temperature reaches 321 °C, which is higher than that of 1-alkyl-3-methylimidazolium halides IL. Further photocatalytic performances of the IL were measured via degrading dye rhodamine B(RB) in aqueous solution under the UV light irradiation. The experiments show that the conversion of RB reaches 80.5% after 90 min under UV-light and the degradation efficiency depends on the pH value of the solution, irradiation time and the dosage of the IL and so on.展开更多
Cu2O nanocubes and Cu nanoparticles were prepared by reducing Cu( Ⅱ ) salt with ethanol as the reducing agent and solvent in the presence of multidentate ligand poly(vinylpyrrolidone) (PVP) under different cond...Cu2O nanocubes and Cu nanoparticles were prepared by reducing Cu( Ⅱ ) salt with ethanol as the reducing agent and solvent in the presence of multidentate ligand poly(vinylpyrrolidone) (PVP) under different conditions. The morphologies and the crystalline structures of the products were characterized by using scanning electron microscopy (SEM), transmission electron microscopy(TEM), selected-area electron diffraction( SAED), and powder X-ray diffraction(XRD). In particular, the influences of the solvothennal reaction temperature and alkalinity on the products were investigated. A lower temperature and a lower alkali concentration favor the formation of the Cu2O phase, whereas a higher temperature and a higher alkali concentration generally lead to the formation of the Cu phase.展开更多
Cupric hydroxide films with a new hierarchical architecture consisting of beautiful nanotubes and nanoflowers were directly fabricated on copper substrate via a solution-immersion process at a constant temperature of ...Cupric hydroxide films with a new hierarchical architecture consisting of beautiful nanotubes and nanoflowers were directly fabricated on copper substrate via a solution-immersion process at a constant temperature of 23 ℃. Stable superhydrophobic Cu(OH)2 surface was obtained after Cu(OH)2 films were modified with hydrolyzed 1H, 1H, 2H, 2H-perfluorooctyltrichlorosilane (CsH4CI3F13Si, FOTMS). The surface morphology and composition of the film were studied using scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), respectively. Result shows that the surface of Cu(OH)2 films directly grown on copper substrate was hydrophilic, whereas the modified Cu(OH)2 films exhibited the superhydrophobicity with a water contact angle (CA) of about 160.8°, as well as a small sliding angle (SA) of about 1°. The special hierarchical structure, along with the slow surface energy leads to the high superhydrophobicity of the surface.展开更多
基金supported by the 973 plan item under Grants(2003CB615802)
文摘A novel micro-micro/mesoporous aluminosilicate ZSM-5-Y/MCM-41 composite molecular sieve with a MCM-41 type structure was synthesized through a novel process of the self-assembly of CTAB surfactant micellae with silica-alumina source originated from alkaline treatment of ZSM-5 zeolite.The physical properties of the ZSM-5- Y/MCM-41 composite molecular sieve were characterized by XRD,Py-FTIR and N_2 adsorption-desorption techniques. Different kinds of molecular sieves including ZSM-5,Y zeolite,Al-MCM-41,ZSM-5/MCM-41 and ZSM-5-Y/MCM- 41 as cracking catalysts were investigated,using 1,3,5-triisopropylbenzene(1,3,5-TIPB) as the probe molecule.Catalytic tests showed that the ZSM-5-Y/MCM-41 composite molecular sieve exhibited higher catalytic activity compared with the microporous ZSM-5 zeolite,Y zeolite,mesoporous Al-MCM-41 molecular sieve and ZSM-5/MCM-41 composite molecular sieve under the same conditions.The remarkable catalytic activity was mainly attributed to the presence of the hierarchical pore structure and proper acidity in the ZSM-5-Y/MCM-41 composite catalyst.Meanwhile, a carbenium ion mechanism was put forward for the cracking of 1,3,5-TIPB.
基金financially supported by the National Key R&D Program of China(2021YFA1502400)the"Transformational Technologies for Clean Energy and Demonstration"+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA2100000)the National Natural Science Foundation of China(52172005,21905295,22179141)the DNL Cooperation Fund,CAS(DNL202008)the Photon Science Center for Carbon Neutrality and the Major Scientific and Technological Innovation Project of Shandong Province(2020CXGC010402)。
文摘Perovskite-type mixed protonic-electronic conducting membranes have attracted attention because of their ability to separate and purify hydrogen from a mixture of gases generated by industrial-scale steam reforming based on an ion diffusion mechanism.Exploring cost-effective membrane materials that can achieve both high H_(2) permeability and strong CO_(2)-tolerant chemical stability has been a major challenge for industrial applications.Herein,we constructed a triple phase(ceramic-metal-ceramic)membrane composed of a perovskite ceramic phase BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ)(BZCYYb),Ni metal phase and a fluorite ceramic phase CeO_(2).Under H_(2) atmosphere,Ni metal in-situ exsolved from the oxide grains,and decorated the grain surface and boundary,thus the electronic conductivity and hydrogen separation performance can be promoted.The BZCYYbNi-CeO_(2)hybrid membrane achieved an exceptional hydrogen separation performance of 0.53 mL min^(-1)cm^(-2) at 800℃ under a 10 vol% H_(2) atmosphere,surpassing all other perovskite membranes reported to date.Furthermore,the CeO_(2) phase incorporated into the BZCYYb-Ni effectively improved the CO_(2)-tolerant chemical stability.The BZCYYbNi-CeO_(2) membrane exhibited outstanding long-term stability for at least 80 h at 700℃ under 10 vol%CO_(2)-10 vol%H_(2).The success of hybrid membrane construction creates a new direction for simultaneously improving their hydrogen separation performance and CO_(2) resistance stability.
基金Australian Centre for Neutron ScatteringAustralian Nuclear Science and Technology Organisation,Grant/Award Number:MI8046+1 种基金Max Planck-POSTECH-Hsinchu Center for Complex Phase MaterialsHigh-Performance Computing Center of Nanjing Tech University。
文摘Electrochemical carbon dioxide(CO_(2))reduction(ECR)is a promising technology to produce valuable fuels and feedstocks from CO_(2).Despite large efforts to develop ECR catalysts,the investigation of the catalytic performance and electrochemical behavior of complex metal oxides,especially perovskite oxides,is rarely reported.Here,the inorganic perovskite oxide Ag-doped(La_(0.8)Sr_(0.2))_(0.95)Ag_(0.05)MnO_(3-δ)(LSA0.05M)is reported as an efficient electrocatalyst for ECR to CO for the first time,which exhibits a Faradaic efficiency(FE)of 84.3%,a remarkable mass activity of 75Ag^(-1)(normalized to the mass of Ag),and stability of 130 h at a moderate overpotential of 0.79 V.The LSA0.05M catalyst experiences structure reconstruction during ECR,creating the in operando-formed interface between the perovskite and the evolved Ag phase.The evolved Ag is uniformly distributed with a small particle size on the perovskite surface.Theoretical calculations indicate the reconstruction of LSA0.05M during ECR and reveal that the perovskite-Ag interface provides adsorption sites for CO_(2) and accelerates the desorption of the*CO intermediate to enhance ECR.This study presents a novel high-performance perovskite catalyst for ECR andmay inspire the future design of electrocatalysts via the in operando formation of metal-metal oxide interfaces.
基金supported by the National Natural Science Foundation of China (Grant No. 52272265)the National Key R&D Program of China (Grant Nos. 2023YFA1607400 and 2018YFA0704300)+4 种基金the support from the National Natural Science Foundation of China (Grant Nos. 52271016 and 52188101)the support from Analytical Instrumentation Center (# SPST-AIC10112914), SPST, Shanghai Tech Universitythe European Research Council (ERC Advanced Grant No. 742068 ‘TOPMAT’)the DFG through SFB 1143 (Project ID 247310070)the Würzburg-Dresden Cluster of Excellence on Complexity and Topology in Quantum Matter ct.qmat (EXC2147,Project ID 390858490)。
文摘Recently, giant intrinsic anomalous Hall effect(AHE) has been observed in the materials with kagome lattice.Here, we systematically investigate the influence of high pressure on the AHE in the ferromagnet LiMn_(6)Sn_(6) with clean Mn kagome lattice. Our in situ high-pressure Raman spectroscopy indicates that the crystal structure of LiMn_(6)Sn_(6) maintains a hexagonal phase under high pressures up to 8.51 GPa. The anomalous Hall conductivity(AHC) σ_(xy)^(A) remains around 150 Ω^(-1)·cm^(-1), dominated by the intrinsic mechanism. Combined with theoretical calculations, our results indicate that the stable AHE under pressure in Li Mn_(6)Sn_(6) originates from the robust electronic and magnetic structure.
基金supported by the National Key Research and Development Program of China (Grant No. 2021YFA1400201)the CAS Project for Young Scientists in Basic Research (Grant No. YSBR059)+5 种基金the Beijing Natural Science Foundation (Grant No. 4191003)the National Natural Science Foundation of China (Grant No. 11774408)the Scientific Instrument Developing Project of the Chinese Academy of Sciences (Grant No. GJJSTD20200005)the Strategic Priority Research Program of Chinese Academy of Sciences (Grant Nos. XDB36000000 and XDB30000000)the International Partnership Program of Chinese Academy of Sciences (Grant No. GJHZ1826)CAS Interdisciplinary Innovation Team。
文摘Controlling collective electronic states hold great promise for development of innovative devices. Here, we experimentally detect the modification of the charge density wave(CDW) phase transition within a 1T-TaS_(2) layer in a WS_(2)/1T-TaS_(2) heterostructure using time-resolved ultrafast spectroscopy. Laser-induced charge transfer doping strongly suppresses the commensurate CDW phase, which results in a significant decrease in both the phase transition temperature(T_(c)) and phase transition stiffness. We interpret the phenomenon that photoinduced hole doping, when surpassing a critical threshold value of ~ 10^(18)cm^(-3), sharply decreases the phase transition energy barrier. Our results provide new insights into controlling the CDW phase transition, paving the way for optical-controlled novel devices based on CDW materials.
基金Supported by the National Natural Science Foundation of China(Nos.20671011,20331010,90406002and90406024)the 111 Project(No.B07012)the Key Laboratory of Structural Chemistry Foundation(No.060017).
文摘A novel flower-like hydrated magnesium carbonate hydroxide, Mg5 (CO3 )4 (OH)2·4H2O, with micro-structure composed of individual thin nano-sheets was synthesized using a facile solution route without the use of template or organic surfactant. Reaction time has an important effect on the final morphology of the product. The micro-structure and morphology of Mg5 (CO3)4 (OH)2·4H2O were characterized by means of X-ray diffractometry (XRD), fieldemission scanning electron microscopy(FE-SEM). Brunauer-Emmett-Teller(BET) surface areas of the samples were also measured. The probable formation mechanism of flower-like micro-structure was discussed. It was found that Mg5 (CO3)4( OH)2·4H2O with flower-like micro-structure was a novel and efficient catalyst for the synthesis of diphenyl carbonate (DPC) by transesterification of dimethyl carbonate (DMC) with phenol.
基金This work was financially supported by the European Research Council(ERC Advanced Grant No.291472'Idea Heusler1)and the ERC Advanced Grant(No.742068)TOPMAT.K.C.was funded by the National Natural Science Foundation of China(Grant No.12074038)J.H.and S.P.were supported by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)No.314790414.
文摘2H-MoS_(2) is a well-studied and promising non-noble metal electrocatalyst for heterogeneous reactions,such as the hydrogen evolution reaction(HER).The performance is largely limited by the chemically inert basal plane,which is unfavorable for surface adsorption and reactions.Herein,we report a facile method to boost the HER activities of 2H-MoS_(2) by coupling with epitaxial Bi2Te3 topological insulator films.The as-obtained MoS_(2)/Bi2Te3/SrTiO3 catalyst exhibits prominent HER catalytic activities compared to that of pure MoS_(2) structures,with a 189 mV decrease in the overpotential required to reach a current density of 10 mA cm^(−2) and a low Tafel slope of 58 mV dec−1.Theoretical investigations suggest that the enhanced catalytic activity originates from the charge redistribution at the interface between the Bi2Te3topological insulator films and the MoS_(2) layer.The delocalized sp-derived topological surface states could denote electrons to the MoS_(2) layer and activate the basal plane for hydrogen adsorption.This study demonstrates the potential of manipulating topological surface states to design high-performance electrocatalysts.
基金Supported by the National Natural Science Foundation of China(Nos.20773014,20933001)
文摘Superhydrophobic surface was prepared on the zinc substrate by chemical solution method via immersing clean pure zinc substrate into a water solution of zinc nitrate hexahydrate[Zn(NO3)2.6H2O] and hexamethylenete- traamine(C6H12N4) at 95 ℃ in water bath for 1.5 h, then modified with 18 alkanethiol. The best resulting surface shows superhydrophobic properties with a water contact angle of about 158° and a low water roll-off angle of around 3°. The prepared samples were characterized by powder X-ray diffraction(XRD), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy(EDX), transmission electron microscopy(TEM), and scanning electron microscopy(SEM). SEM images of the films show that the resulting surface exhibits flower-shaped micro- and nano-structure. The surfaces of the prepared films were composed of ZnO nanorods which were wurtzite structure. The special flower-like micro- and nano-structure along with the low surface energy leads to the surface superhydro- phobicity.
基金financially supported by the National Key R&D Program of China(2020YFB1505802)the Ministry of Science and Technology of China(2017YFA0208200)+2 种基金the National Natural Science Foundation of China(22025108,U21A20327,22121001)Guangdong Provincial Natural Science Fund for Distinguished Young Scholars(2021B1515020081)the start-up support from Xiamen University。
文摘Photocatalytic water splitting has emerged as a new frontier for converting solar energy to green H_(2) and value-added chemicals.Nevertheless,great challenges still remain for developing efficient photocatalysts for pure water splitting without sacrificial agents.In this work,we demonstrate that doping hexagonal ZnIn_(2)S_(4)(ZIS) with Pd single atoms(Pd_(0.03)/ZIS) can serve as a highly efficient photocatalyst for pure water splitting to simultaneously produce H_(2) and H_(2)O_(2) without any sacrificial agents.Results from aberration-corrected high-angle annular dark field scanning transmission electron microscopy,X-ray fine spectroscopy,insitu electron paramagnetic resonance and diffuse Fourier transform infrared spectroscopy reveal that doping ZIS with Pd single atoms facilitates the formation of S vacancies(S_(v)),where the photogenerated electrons can transfer to Pd single atoms,as a result of enhanced separation of electron-hole pairs and improved photocatalytic performance.Impressively,Pd_(0.03)/ZIS displays a stoichiometric ratio of H_(2) and H_(2)O_(2) with the productivity of 1,037.9 and 1,021.4μmol g^(-1)h^(-1),respectively,which has largely outperformed pure ZIS and other reported catalysts for pure water splitting.This work provides an efficient photocatalyst for water splitting to produce H_(2) and H_(2)O_(2),which may attract rapid interest in materials science,chemistry,and heterogeneous catalysis.
文摘The one-pot synthesis of dimethyl carbonate(DMC) with co-production of propy-lene carbonate(PC) and propylene glycol(PG) from propylene oxide( PO), carbon dioxide and methanol as the starting materials was investigated. The catalyst adopted here was a mixture of tetrabutyl ammonium bromide and sodium methoxide. It was found that un- der the reaction conditions of t = 150 ℃, p =3-4 MPa and 2 h, the PO conversion could reach 100%, the DMC, PC and the PG selectivities were 49. 7%, 42. 7% and 49. 8%, respectively, and the selectivity of by-products was below 10%.
基金This work was supported by the National Natural Science Foundation of China (Nos. 20671011, 20331010, 90406002 and 90406024)the 111 Project (B07012) and Key Laboratory of Structural Chemistry Foundation (No. 060017)
文摘A new three-dimensional supramolecule composed of copper-Schiff base complex, [Cu(naphdien)]Cl·H2O, where naphdien is Schiff base of 2-hydroxy-1-naphthaldehyde and diethylenetriamine, has been synthesized and determined by single-crystal X-ray diffraction. It belongs to the monoclinic system, space group P21/c, with a = 7.3490(15), b = 7.0847(16), c = 30.845(3)A, β= 95.33(3)°, V = 1599.0(5)A3, Z = 4, C15 H20ClCuN3O2, Mr = 373.33, De = 1.551 g/cm3, μ = 1.543 mm^-1, F(000) = 772, R = 0.0536 and wR = 0.0927 for 2788 unique reflections with 1659 observed ones (I 〉2σ(I)). In the crystal structure, mononuclear units [Cu(naphdien)]Cl·H2O are linked into a two-dimensional framework via strong hydrogen bonds, and extended into a three-dimensional supramolecular structure through π-π stacking interactions.
文摘The hierarchically structured ZSM-5 monolith was prepared through transforming the skeletons of the macroporous silica gel into ZSM-5 by the steam-assisted conversion method. The morphology and monolithic shapes of macroporous silica gel were well preserved. The hierarchically structured ZSM-5 monolith exhibited the hierarchical porosity, with mesopores and macropores existing inside the macroporous silica gel, and micropores formed by the ZSM-5. The products have been characterized properly by using the XRD, SEM and N2 adsorption–desorption methods.
基金Supported by the National Natural Science Foundation of China(Nos20731002, 10876002)the Specialized Research Fund for the Doctoral Program of Higher Education of China(No200800070015)+2 种基金the Program of Cooperation of the Beijing Education Commission, China(No20091739006)the Program of Cooperation of the Beijing Technology Commission, China(No Z09010300820902)the Program for New Century Excellent Talents in University of China
文摘The polyoxometalate-imidazole ionic liquids(POM-ILs) with low melting points at 94.5 and 95.5 ℃, [Cn mim]a[MosO26](Cn mim=1-alkyl-3-methylimidazolium, n=12,14), have been successfully synthesized and characterized by DSC, single-crystal X-ray diffraction and TGA, etc. The two POM-ILs have relatively high stability with decomposing temperature up to about 347 and 344 ℃, respectively. Further photocatalytic performance was measured via the degradation of rhodamine B(RB) in aqueous solution. The experiments show that the conversion reached to 90% after 90 min under UV-light and the degradation efficiency depended on pH value, different dosages and so on. In addition, the catalysts can be recycled for several times without significant loss of activity.
基金Project supported by CAS-Shanghai Science Research Center,China(Grant No.CAS-SSRC-YH-2015-01)the National Key R&D Program of China(Grant No.2017YFA0305400)+4 种基金the National Natural Science Foundation of China(Grant Nos.11674229,11227902,and 11604207)the EPSRC Platform Grant(Grant No.EP/M020517/1)Hefei Science Center,Chinese Academy of Sciences(Grant No.2015HSC-UE013)Science and Technology Commission of Shanghai Municipality,China(Grant No.14520722100)the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant No.XDB04040200)。
文摘Iron-based superconductor family FeX(X=S,Se,Te)has been one of the research foci in physics and material science due to their record-breaking superconducting temperature(FeSe film)and rich physical phenomena.Recently,FeS,the least studied Fe X compound(due to the difficulty in synthesizing high quality macroscopic crystals)attracted much attention because of its puzzling superconducting pairing symmetry.In this work,combining scanning tunneling microscopy and angle resolved photoemission spectroscopy(ARPES)with sub-micron spatial resolution,we investigate the intrinsic electronic structures of superconducting FeS from individual single crystalline domains.Unlike FeTe or FeSe,FeS remains identical tetragonal structure from room temperature down to 5 K,and the band structures observed can be well reproduced by our ab-initio calculations.Remarkably,mixed with the 1×1 tetragonal metallic phase,we also observe the coexistence of √5×√5 reconstructed insulating phase in the crystal,which not only helps explain the unusual properties of FeS,but also demonstrates the importance of using spatially resolved experimental tools in the study of this compound.
基金Supported by the National Natural Science Foundation of China (Nos 20801004/B01, 20871016/B0101, 10876002/A06)the 111 Project (B07012)Excellent Young Scholars Research Fund of Beijing Institute of Technology (No 2006Y0715)
文摘The title complex {[AgL]ClO4}n(L=2,5-bis(3-pyridinylmethylthio)-1,3,4-thiadiazole) was synthesized by the reaction of Ag(I) salt and a novel flexible ligand L.Its structure was determined by X-ray crystallography with the following data:monoclinic,space group P21/n,a=16.5068(13),b=7.6548(4),c=16.5521(13)A,β=115.119(3)o,V=1893.7(2)A^3,Z=4,Dc=1.893 g/cm^3,μ=1.565 mm^-1,F(000)=1072,C14H12AgClN4O4S3,Mr=539.78,T=293(2) K,S=1.067,the final R=0.0342 and wR=0.0870.The silver ion in the complex is in a trigonal coordination geometry to link three different L.Meanwhile,each L connects three different silver ions by its N coordination sites to form a two-dimensional layer structure.
基金Supported by the National Natural Science Foundation of China(Nos.2067101120731002+3 种基金20801004 10876002 20801005)the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.200800070015).
文摘The polyoxometalate(POM)-imidazole ionic liquid(IL) [C8mim]2[Mo6O19](C8mim=1-methyl-3-octylimi- dazolium) with a low melting point of 82.6 °C was successfully prepared and characterized by FTIR, XPS, NMR, TG and so on. The polyoxomolybdate-based IL has high stability, and its decomposing temperature reaches 321 °C, which is higher than that of 1-alkyl-3-methylimidazolium halides IL. Further photocatalytic performances of the IL were measured via degrading dye rhodamine B(RB) in aqueous solution under the UV light irradiation. The experiments show that the conversion of RB reaches 80.5% after 90 min under UV-light and the degradation efficiency depends on the pH value of the solution, irradiation time and the dosage of the IL and so on.
基金Supported by the National Natural Science Foundation of China(Nos. 20331010 and 90406002) and Specialized ResearchFund for the Doctoral Program of Higher Education(No. 20030007014).
文摘Cu2O nanocubes and Cu nanoparticles were prepared by reducing Cu( Ⅱ ) salt with ethanol as the reducing agent and solvent in the presence of multidentate ligand poly(vinylpyrrolidone) (PVP) under different conditions. The morphologies and the crystalline structures of the products were characterized by using scanning electron microscopy (SEM), transmission electron microscopy(TEM), selected-area electron diffraction( SAED), and powder X-ray diffraction(XRD). In particular, the influences of the solvothennal reaction temperature and alkalinity on the products were investigated. A lower temperature and a lower alkali concentration favor the formation of the Cu2O phase, whereas a higher temperature and a higher alkali concentration generally lead to the formation of the Cu phase.
基金Sponsored by the National Natural Science Foundation of China(20773014/B030202)the "111" Project of China(B07012)
文摘Cupric hydroxide films with a new hierarchical architecture consisting of beautiful nanotubes and nanoflowers were directly fabricated on copper substrate via a solution-immersion process at a constant temperature of 23 ℃. Stable superhydrophobic Cu(OH)2 surface was obtained after Cu(OH)2 films were modified with hydrolyzed 1H, 1H, 2H, 2H-perfluorooctyltrichlorosilane (CsH4CI3F13Si, FOTMS). The surface morphology and composition of the film were studied using scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), respectively. Result shows that the surface of Cu(OH)2 films directly grown on copper substrate was hydrophilic, whereas the modified Cu(OH)2 films exhibited the superhydrophobicity with a water contact angle (CA) of about 160.8°, as well as a small sliding angle (SA) of about 1°. The special hierarchical structure, along with the slow surface energy leads to the high superhydrophobicity of the surface.