Photocatalytic hydrogen production coupled with selective oxidation of organic substrates to produce highvalue-added fine chemicals has drawn increasing attention.Herein,we report a noble metal-free photocatalyst for ...Photocatalytic hydrogen production coupled with selective oxidation of organic substrates to produce highvalue-added fine chemicals has drawn increasing attention.Herein,we report a noble metal-free photocatalyst for the highly efficient and simultaneous generation of hydrogen and the selective oxidation of benzyl alcohol into benzaldehyde over Cd S@Mo S2 heterostructures under visible light.Without the need for a sacrificial agent,Cd S@Mo S2 displayed an excellent hydrogen production rate of 4233μmol g^-1h^-1with0.3 mmol benzyl alcohol,which is approximately 53 times higher than that of bare Cd S nanorods(80μmol g^-1h^-1).The reaction system was highly selective for the oxidation of benzyl alcohol into benzaldehyde.When the amount of benzyl alcohol increased to 1.0 mmol,the hydrogen production reached9033μmol g^-1h^-1.Scanning electron microscopy and transmission electron microscopy images revealed that p-type Mo S2 sheets with a flower-like structure closely adhered to n-type semiconductor Cd S nanorods through the formation of a p-n heterojunction.As a potential Z-scheme photocatalyst,the Cd S@Mo S2 heterostructure effectively produces and separates electron-hole pairs under visible light.Thus,the electrons are used for reduction to generate hydrogen,and the holes oxidize benzyl alcohol into benzaldehyde.Moreover,a mechanism of photogenerated charge transfer and separation was proposed and verified by photoluminescence,electrochemical impedance spectroscopy,photocurrent and Mott-Schottky measurements.The results reveal that the Cd S@Mo S2 heterojunctions have rapid and efficient charge separation and transfer,thereby greatly improving benzyl alcohol dehydrogenation.This work provides insight into the rational design of high-performance Z-scheme photocatalysts and the use of holes and electrons to obtain two valuable chemicals simultaneously.展开更多
The special electronic characteristics and high atom usage efficiency of metal-nitrogen-carbon(M-N-C)materials have made them extremely attractive for oxygen reduction reactions(ORRs).However,it is inevitable that hyd...The special electronic characteristics and high atom usage efficiency of metal-nitrogen-carbon(M-N-C)materials have made them extremely attractive for oxygen reduction reactions(ORRs).However,it is inevitable that hydrogen peroxide(H_(2)O_(2))will be formed via the two-electron pathway in ORRs.Herein,the Cu nanoparticles(NPs)have been encapsulated into Ni doped hollow mesoporous carbon spheres(Ni-HMCS)to reduce the generation of H_(2)O_(2)in ORR.Electrochemical tests confirm that the introduction of Cu NPs improves the ORR performance greatly.The obtained Cu/Ni-HMCS exhibits a half-wave potential of 0.82 V vs.reversible hydrogen electrode and a limited current density of 5.5 mA cm^(-2),which is comparable with the commercial Pt/C.Moreover,Cu/Ni-HMCS has been used in Zn-air battery,demonstrating a high power density of 161 mW cm^(-2)and a long-term recharge capability(50 h at 5 mA cm^(-2)).The theoretical calculation proposes a tandem catalysis pathway for Cu/Ni multi-sites catalysis,that is,H_(2)O_(2)released from the Ni-N_(4)and Cu-N_(4)sites migrates to the Cu(111)face,on which the captive H_(2)O_(2)is further reduced to H_(2)O.This work demonstrates an interesting tandem catalytic pathway of dual-metal multi-sites for ORR,which provides an insight into the development of effective fuel cell electrocatalysts.展开更多
The fabrication and structure characterization of a self-assemble film were reported.An orderded layer structure ultrathin film was formed by alternative deposition of poly(sodium 4-styrenesulfonate)as polyanion and b...The fabrication and structure characterization of a self-assemble film were reported.An orderded layer structure ultrathin film was formed by alternative deposition of poly(sodium 4-styrenesulfonate)as polyanion and benzidine dihydrochloride as cationic compounds.UV-visible absorption spectrum,contact angle measurement and ellipsometry measurement were conducted to characterize the film.展开更多
A novel Cu（II）-2,2＇-bipy-supported （bipy = bipyridine） mixed valence decatungstate, [Cu（2,2＇-bipy）2]2Na2W6^VW4^VIO30·2H2O 1, has been synthesized and structurally characterized by X-ray analysis. The crys...A novel Cu（II）-2,2＇-bipy-supported （bipy = bipyridine） mixed valence decatungstate, [Cu（2,2＇-bipy）2]2Na2W6^VW4^VIO30·2H2O 1, has been synthesized and structurally characterized by X-ray analysis. The crystal of 1 is of triclinic, space group P1^- with a= 10.9393（10）, b = 12.0492（2）, c = 12.3783（2）A, a = 80.631（10）, β= 70.226（10）, γ= 72.329（9）^o, V = 1459.64（4）A^3, Z = 1, Dc = 3.582 g/cm^3, F（000） = 1404, R = 0.0553 and wR = 0.1242 for 4607 observed reflections （I 〉 2σ（I））. The EPR spectrum of 1 indicates that its unpaired electrons are placed in the dx2-y2 orbital of the ground state of Cun. Furthermore, compound 1 shows an antiferromagnetic interaction.展开更多
Three novel amino acid salts of 12-molybdosilicate formulated （Gly）6H4SiMo12O40·8H2O 1, K3（HGly）SiMol2O40·4H2O 2 and K2（HGly）2SiMo12O40·9H2O 3 （Gly = NH3CH2COO） were synthesized and characteriz...Three novel amino acid salts of 12-molybdosilicate formulated （Gly）6H4SiMo12O40·8H2O 1, K3（HGly）SiMol2O40·4H2O 2 and K2（HGly）2SiMo12O40·9H2O 3 （Gly = NH3CH2COO） were synthesized and characterized by elemental analysis, IR and single-crystal X-ray analysis. Compound 1 crystallizes in trigonal, space group R-3 with a = 17.0742（3）, b = 17.0742（3）, c = 16.792（4）A°, γ = 120°, F（000） = 3474, Mr = 2413.92, Z = 3, V = 4239.4（14）A°^3, Dc = 2.837 g/cm^3,μ（MoKα） = 2.728 mm^-1, the final R = 0.0622, wR = 0.1549 （I 〉 2σ（I）） and GOF = 1.143. In compound 1, each [SiMo12O40]^4- unit is surrounded by six Gly molecules through hydrogen bonding. Compounds 2 and 3 crystallize in monoclinic, space groups P21c and P21/c, respectively. The pH value of the reaction media plays a crucial role in the formations of the three compounds.展开更多
基金supported by the National Key Research and Development Program of China(2017YFA0700102)the National Natural Science Foundation of China(21520102001,21871263 and 21671188)+1 种基金the Key Research Program of Frontier Sciences,CAS(QYZDJ-SSW-SLH045)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20000000)。
文摘Photocatalytic hydrogen production coupled with selective oxidation of organic substrates to produce highvalue-added fine chemicals has drawn increasing attention.Herein,we report a noble metal-free photocatalyst for the highly efficient and simultaneous generation of hydrogen and the selective oxidation of benzyl alcohol into benzaldehyde over Cd S@Mo S2 heterostructures under visible light.Without the need for a sacrificial agent,Cd S@Mo S2 displayed an excellent hydrogen production rate of 4233μmol g^-1h^-1with0.3 mmol benzyl alcohol,which is approximately 53 times higher than that of bare Cd S nanorods(80μmol g^-1h^-1).The reaction system was highly selective for the oxidation of benzyl alcohol into benzaldehyde.When the amount of benzyl alcohol increased to 1.0 mmol,the hydrogen production reached9033μmol g^-1h^-1.Scanning electron microscopy and transmission electron microscopy images revealed that p-type Mo S2 sheets with a flower-like structure closely adhered to n-type semiconductor Cd S nanorods through the formation of a p-n heterojunction.As a potential Z-scheme photocatalyst,the Cd S@Mo S2 heterostructure effectively produces and separates electron-hole pairs under visible light.Thus,the electrons are used for reduction to generate hydrogen,and the holes oxidize benzyl alcohol into benzaldehyde.Moreover,a mechanism of photogenerated charge transfer and separation was proposed and verified by photoluminescence,electrochemical impedance spectroscopy,photocurrent and Mott-Schottky measurements.The results reveal that the Cd S@Mo S2 heterojunctions have rapid and efficient charge separation and transfer,thereby greatly improving benzyl alcohol dehydrogenation.This work provides insight into the rational design of high-performance Z-scheme photocatalysts and the use of holes and electrons to obtain two valuable chemicals simultaneously.
基金supported by the National Key Research and Development Program of China(2021YFA1501500 and 2018YFA0704502)the National Natural Science Foundation of China(22171265,22201286,22033008 and 22220102005)+2 种基金Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZZ103)the Open Research Fund of CNMGE Platform&NSCC-TJthe Open Science Promotion Plan 2023 of CSTCloud。
文摘The special electronic characteristics and high atom usage efficiency of metal-nitrogen-carbon(M-N-C)materials have made them extremely attractive for oxygen reduction reactions(ORRs).However,it is inevitable that hydrogen peroxide(H_(2)O_(2))will be formed via the two-electron pathway in ORRs.Herein,the Cu nanoparticles(NPs)have been encapsulated into Ni doped hollow mesoporous carbon spheres(Ni-HMCS)to reduce the generation of H_(2)O_(2)in ORR.Electrochemical tests confirm that the introduction of Cu NPs improves the ORR performance greatly.The obtained Cu/Ni-HMCS exhibits a half-wave potential of 0.82 V vs.reversible hydrogen electrode and a limited current density of 5.5 mA cm^(-2),which is comparable with the commercial Pt/C.Moreover,Cu/Ni-HMCS has been used in Zn-air battery,demonstrating a high power density of 161 mW cm^(-2)and a long-term recharge capability(50 h at 5 mA cm^(-2)).The theoretical calculation proposes a tandem catalysis pathway for Cu/Ni multi-sites catalysis,that is,H_(2)O_(2)released from the Ni-N_(4)and Cu-N_(4)sites migrates to the Cu(111)face,on which the captive H_(2)O_(2)is further reduced to H_(2)O.This work demonstrates an interesting tandem catalytic pathway of dual-metal multi-sites for ORR,which provides an insight into the development of effective fuel cell electrocatalysts.
文摘The fabrication and structure characterization of a self-assemble film were reported.An orderded layer structure ultrathin film was formed by alternative deposition of poly(sodium 4-styrenesulfonate)as polyanion and benzidine dihydrochloride as cationic compounds.UV-visible absorption spectrum,contact angle measurement and ellipsometry measurement were conducted to characterize the film.
基金Supported by the NNSFC (90206040)NSF of Fujian Province (2006F3134, 2005J058)
文摘A novel Cu（II）-2,2＇-bipy-supported （bipy = bipyridine） mixed valence decatungstate, [Cu（2,2＇-bipy）2]2Na2W6^VW4^VIO30·2H2O 1, has been synthesized and structurally characterized by X-ray analysis. The crystal of 1 is of triclinic, space group P1^- with a= 10.9393（10）, b = 12.0492（2）, c = 12.3783（2）A, a = 80.631（10）, β= 70.226（10）, γ= 72.329（9）^o, V = 1459.64（4）A^3, Z = 1, Dc = 3.582 g/cm^3, F（000） = 1404, R = 0.0553 and wR = 0.1242 for 4607 observed reflections （I 〉 2σ（I））. The EPR spectrum of 1 indicates that its unpaired electrons are placed in the dx2-y2 orbital of the ground state of Cun. Furthermore, compound 1 shows an antiferromagnetic interaction.
基金This work was supported by the National Natural Science Foundation of China (50472021) and the "One-hundred Talent "Project from the Chinese Academy of Sciences
文摘Three novel amino acid salts of 12-molybdosilicate formulated （Gly）6H4SiMo12O40·8H2O 1, K3（HGly）SiMol2O40·4H2O 2 and K2（HGly）2SiMo12O40·9H2O 3 （Gly = NH3CH2COO） were synthesized and characterized by elemental analysis, IR and single-crystal X-ray analysis. Compound 1 crystallizes in trigonal, space group R-3 with a = 17.0742（3）, b = 17.0742（3）, c = 16.792（4）A°, γ = 120°, F（000） = 3474, Mr = 2413.92, Z = 3, V = 4239.4（14）A°^3, Dc = 2.837 g/cm^3,μ（MoKα） = 2.728 mm^-1, the final R = 0.0622, wR = 0.1549 （I 〉 2σ（I）） and GOF = 1.143. In compound 1, each [SiMo12O40]^4- unit is surrounded by six Gly molecules through hydrogen bonding. Compounds 2 and 3 crystallize in monoclinic, space groups P21c and P21/c, respectively. The pH value of the reaction media plays a crucial role in the formations of the three compounds.
