The valence states and coordination structures of doped heterometal atoms in two-dimensional(2D)nanomaterials lack predictable regulation strategies.Hence,a robust method is proposed to form unsaturated heteroatom clu...The valence states and coordination structures of doped heterometal atoms in two-dimensional(2D)nanomaterials lack predictable regulation strategies.Hence,a robust method is proposed to form unsaturated heteroatom clusters via the metal-vacancy restraint mechanism,which can precisely regulate the bonding and valence state of heterometal atoms doped in 2D molybdenum disulfide.The unsaturated valence state of heterometal Pt and Ru cluster atoms form a spatial coordination structure with Pt–S and Ru–O–S as catalytically active sites.Among them,the strong binding energy of negatively charged suspended S and O sites for H+,as well as the weak adsorption of positively charged unsaturated heterometal atoms for H*,reduces the energy barrier of the hydrogen evolution reaction proved by theoretical calculation.Whereupon,the electrocatalytic hydrogen evolution performance is markedly improved by the ensemble effect of unsaturated heterometal atoms and highlighted with an overpotential of 84 mV and Tafel slope of 68.5 mV dec^(−1).In brief,this metal vacancy-induced valence state regulation of heterometal can manipulate the coordination structure and catalytic activity of heterometal atoms doped in the 2D atomic lattice but not limited to 2D nanomaterials.展开更多
TiO_(2)is the dominant and most widely researched photocatalyst for environmental remediation,however,the drawbacks,such as only responding to UV light(<5%of sunlight),low charge separation efficiency,and difficult...TiO_(2)is the dominant and most widely researched photocatalyst for environmental remediation,however,the drawbacks,such as only responding to UV light(<5%of sunlight),low charge separation efficiency,and difficulties in recycling,have severely hindered its practical application.Herein,we synthesized magnetically separable Fe_(3)O_(4)@MoS_(2)@mesoporous TiO_(2)(FMmT)photocatalysts via a simple,green,and template-free solvothermal method combined with ultrasonic hydrolysis.It is found that FMmT possesses a high specific surface area(55.09 m2·g−1),enhanced visible-light responsiveness(~521 nm),and remarkable photogenerated charge separation efficiency.In addition,the photocatalytic degradation efficiencies of FMmT for methylene blue(MB),rhodamine B(RhB),and tetracycline(TC)are 99.4%,98.5%,and 89.3%within 300 min,respectively.The corresponding degradation rates are 4.5,4.3,and 3.1 times higher than those of pure TiO_(2)separately.Owing to the high saturation magnetization(43.1 A·m^(2)·kg^(−1)),FMmT can achieve effective recycling with an applied magnetic field.The improved photocatalytic activity is closely related to the effective transport of photogenerated electrons by the active interlayer MoS_(2) and the electron–hole separation caused by the MoS_(2)@TiO_(2)heterojunction.Meanwhile,the excellent light-harvesting ability and abundant reactive sites of the mesoporous TiO_(2)shell further boost the photocatalytic efficiency of FMmT.This work provides a new approach and some experimental basis for the design and performance improvement of magnetic photocatalysts by innovatively incorporating MoS2 as the active interlayer and integrating it with a mesoporous shell.展开更多
3D flower-like hierarchical mesoporous Bi_(4)O_(5)I_(2)/MoS_(2)Z-scheme layered heterojunction photocatalyst was fabricated by oil bath and hydrothermal methods.The heterojunction with narrow band gap of~1.95 eV exten...3D flower-like hierarchical mesoporous Bi_(4)O_(5)I_(2)/MoS_(2)Z-scheme layered heterojunction photocatalyst was fabricated by oil bath and hydrothermal methods.The heterojunction with narrow band gap of~1.95 eV extended the photoresponse to near-infrared region,which showed obvious photothermal effect due to the introduction of MoS_(2) with broad spectrum response.MoS_(2) nanosheets were anchored onto the surface of flower-like hierarchical mesoporous Bi_(4)O_(5)I_(2) nanosheets,thereby forming efficient layered heterojunctions,the solar-driven photocatalytic efficiency in degradation of highly toxic dichlorophenol and reduction of hexavalent chromium was improved to 98.5%and 99.2%,which was~4 and 7 times higher than that of the pristine Bi_(4)O_(5)I_(2),respectively.In addition,the photocatalytic hydrogen production rate reached 496.78 μmol h^(-1)g^(-1),which was~6 times higher than that of the pristine Bi_(4)O_(5)I_(2).The excellent photocatalytic performance can be ascribed to the promoted photothermal effect,as well as,the formation of compact Z-scheme layered heterojunctions.The 3D flower-like hierarchical mesoporous structure provided adequate surface active-sites,which was conducive to the mass transfer.Moreover,the high stability of the prepared photocatalyst further promoted its potential practical application.This strategy also provides new insights for fabricating layered Zscheme heterojunctions photocatalysts with highly photothermal-photocatalytic efficiency.展开更多
The role of nano-SiO 2 and ultra-fine boron carbide on the properties of alumina-graphite materials was investigated. The study showed that the ultra-fine boron carbide added modified the microstructure of residual c...The role of nano-SiO 2 and ultra-fine boron carbide on the properties of alumina-graphite materials was investigated. The study showed that the ultra-fine boron carbide added modified the microstructure of residual carbon and promoted the chemical bond between residual carbon from phenolic resin and flake graphite. The carbon white could strengthen the residual carbon from phenolic resin. These two additives improved the mechanical properties of AG refractories at both room temperature and high temperature, and thermal shock resistance was improved noticeably. When the two additives were doped together, carbon white could retard the evaporation of B 2O 3. Thermal shock resistance was guaranteed with a smaller amount of ultra-fine boron carbide.展开更多
Al<sub>2</sub>S<sub>3</sub>/MoS<sub>2</sub> nanocomposite has been synthesized through electrochemical method and characterized by UV-Visible spectroscopy, XRD, SEM and EDAX data. U...Al<sub>2</sub>S<sub>3</sub>/MoS<sub>2</sub> nanocomposite has been synthesized through electrochemical method and characterized by UV-Visible spectroscopy, XRD, SEM and EDAX data. UV-Visible spectroscopy measurements reveal that the Al<sub>2</sub>S<sub>3</sub>/MoS<sub>2</sub> nanocomposite has maximum absorption at 353.04 nm and this peak position reflects the band gap of particles and it is found to be 2.51 eV which was calculated using Tauc plot. X-Ray diffraction (XRD) reveals crystaline size to be 49.85 nm which was calculated using Williamson-Hall (W-H) plot method. Photocatalytic degradation of acetic acid, chloroacetic acid and trichloroacetic acid has been studied by volumetric method using NaOH solution. Photocatalytic degradation of chloroacetic acid and acetic acid follows first order kinetics. The photodegradation efficiency for Al<sub>2</sub>S<sub>3</sub>/MoS<sub>2</sub> nanocomposite was found to be ≈97.8%. A Taft linear free energy relationship is noted for the catalysed reaction with ρ* = 0.233 and indicating electron withdrawing groups enhance the rate. An isokinetic relation is observed with β = 358 K indicating that enthalpy factor controls the reaction rate. The result of this paper suggests the possibility of degradation of organic compounds, industrial effluants and toxic organic compounds by photodegradation process by ecofriendly Al<sub>2</sub>S<sub>3</sub>/ MoS<sub>2</sub>. The antibacterial activity of Al<sub>2</sub>S<sub>3</sub>/MoS<sub>2</sub> nanocomposite was investigated. These particles were shown to have an effective bactericide.展开更多
基金supported by the National Natural Science Foundation of China(22205209,52202373 and U21A200972)China Postdoctoral Science Foundation(2022M722867)Key Research Project of Higher Education Institutions in Henan Province(23A530001)。
文摘The valence states and coordination structures of doped heterometal atoms in two-dimensional(2D)nanomaterials lack predictable regulation strategies.Hence,a robust method is proposed to form unsaturated heteroatom clusters via the metal-vacancy restraint mechanism,which can precisely regulate the bonding and valence state of heterometal atoms doped in 2D molybdenum disulfide.The unsaturated valence state of heterometal Pt and Ru cluster atoms form a spatial coordination structure with Pt–S and Ru–O–S as catalytically active sites.Among them,the strong binding energy of negatively charged suspended S and O sites for H+,as well as the weak adsorption of positively charged unsaturated heterometal atoms for H*,reduces the energy barrier of the hydrogen evolution reaction proved by theoretical calculation.Whereupon,the electrocatalytic hydrogen evolution performance is markedly improved by the ensemble effect of unsaturated heterometal atoms and highlighted with an overpotential of 84 mV and Tafel slope of 68.5 mV dec^(−1).In brief,this metal vacancy-induced valence state regulation of heterometal can manipulate the coordination structure and catalytic activity of heterometal atoms doped in the 2D atomic lattice but not limited to 2D nanomaterials.
基金financially supported by the National Key R & D Projects (Nos. 2021YFC1910504, 2019YFC1907101, 2019YFC1907103, and 2017YFB0702304)the Key R & D Project in Ningxia Hui Autonomous Region, China (No. 2020BCE01001)+6 种基金the Key and Normal Projects National Natural Science Foundation of China (Nos. U2002212 and 51672024)the Xijiang Innovation and Entrepreneurship Team (No. 2017A0109004)the Fundamental Research Funds for the Central Universities (Nos. FRF-BD-20-24A, FRF-TP-20-031A1, FRF-IC-19-017Z, FRF-GF-19-032B, and 06500141)the Integration of Green Key Process Systems MIIT, Natural Science Foundation of Beijing Municipality (No. 2214073)the Guangdong Basic and Applied Research Foundation, China (No. 2020A1515110408)the Foshan Science and Technology Innovation Special Foundation, China (No. BK21BE002)the Postdoctor Research Foundation of Shunde Graduate School of University of Science and Technology Beijing (No. 2020BH004)
文摘TiO_(2)is the dominant and most widely researched photocatalyst for environmental remediation,however,the drawbacks,such as only responding to UV light(<5%of sunlight),low charge separation efficiency,and difficulties in recycling,have severely hindered its practical application.Herein,we synthesized magnetically separable Fe_(3)O_(4)@MoS_(2)@mesoporous TiO_(2)(FMmT)photocatalysts via a simple,green,and template-free solvothermal method combined with ultrasonic hydrolysis.It is found that FMmT possesses a high specific surface area(55.09 m2·g−1),enhanced visible-light responsiveness(~521 nm),and remarkable photogenerated charge separation efficiency.In addition,the photocatalytic degradation efficiencies of FMmT for methylene blue(MB),rhodamine B(RhB),and tetracycline(TC)are 99.4%,98.5%,and 89.3%within 300 min,respectively.The corresponding degradation rates are 4.5,4.3,and 3.1 times higher than those of pure TiO_(2)separately.Owing to the high saturation magnetization(43.1 A·m^(2)·kg^(−1)),FMmT can achieve effective recycling with an applied magnetic field.The improved photocatalytic activity is closely related to the effective transport of photogenerated electrons by the active interlayer MoS_(2) and the electron–hole separation caused by the MoS_(2)@TiO_(2)heterojunction.Meanwhile,the excellent light-harvesting ability and abundant reactive sites of the mesoporous TiO_(2)shell further boost the photocatalytic efficiency of FMmT.This work provides a new approach and some experimental basis for the design and performance improvement of magnetic photocatalysts by innovatively incorporating MoS2 as the active interlayer and integrating it with a mesoporous shell.
基金support of this research by the National Natural Science Foundation of China(21871078)the Natural Science Foundation of Heilongjiang Province(JQ2019B001 and B2018010)+3 种基金the Heilongjiang Postdoctoral Startup Fund(LBH-Q14135)the Heilongjiang University Science Fund for Distinguished Young Scholars(JCL201802)the Heilongjiang Provincial Institutions of Higher Learning Basic Research Funds Basic Research Projects(KJCX201909)the Heilongjiang Touyan Innovation Team Program.
文摘3D flower-like hierarchical mesoporous Bi_(4)O_(5)I_(2)/MoS_(2)Z-scheme layered heterojunction photocatalyst was fabricated by oil bath and hydrothermal methods.The heterojunction with narrow band gap of~1.95 eV extended the photoresponse to near-infrared region,which showed obvious photothermal effect due to the introduction of MoS_(2) with broad spectrum response.MoS_(2) nanosheets were anchored onto the surface of flower-like hierarchical mesoporous Bi_(4)O_(5)I_(2) nanosheets,thereby forming efficient layered heterojunctions,the solar-driven photocatalytic efficiency in degradation of highly toxic dichlorophenol and reduction of hexavalent chromium was improved to 98.5%and 99.2%,which was~4 and 7 times higher than that of the pristine Bi_(4)O_(5)I_(2),respectively.In addition,the photocatalytic hydrogen production rate reached 496.78 μmol h^(-1)g^(-1),which was~6 times higher than that of the pristine Bi_(4)O_(5)I_(2).The excellent photocatalytic performance can be ascribed to the promoted photothermal effect,as well as,the formation of compact Z-scheme layered heterojunctions.The 3D flower-like hierarchical mesoporous structure provided adequate surface active-sites,which was conducive to the mass transfer.Moreover,the high stability of the prepared photocatalyst further promoted its potential practical application.This strategy also provides new insights for fabricating layered Zscheme heterojunctions photocatalysts with highly photothermal-photocatalytic efficiency.
基金Project(2021YFA1401300)supported by the National Key Research and Development Program of ChinaProject(2021RC3021)supported by the Science and Technology Innovation Program of Hunan Province,ChinaProject(2021JJ40780)supported by the Natural Science Foundation of Hunan Province,China。
文摘The role of nano-SiO 2 and ultra-fine boron carbide on the properties of alumina-graphite materials was investigated. The study showed that the ultra-fine boron carbide added modified the microstructure of residual carbon and promoted the chemical bond between residual carbon from phenolic resin and flake graphite. The carbon white could strengthen the residual carbon from phenolic resin. These two additives improved the mechanical properties of AG refractories at both room temperature and high temperature, and thermal shock resistance was improved noticeably. When the two additives were doped together, carbon white could retard the evaporation of B 2O 3. Thermal shock resistance was guaranteed with a smaller amount of ultra-fine boron carbide.
文摘Al<sub>2</sub>S<sub>3</sub>/MoS<sub>2</sub> nanocomposite has been synthesized through electrochemical method and characterized by UV-Visible spectroscopy, XRD, SEM and EDAX data. UV-Visible spectroscopy measurements reveal that the Al<sub>2</sub>S<sub>3</sub>/MoS<sub>2</sub> nanocomposite has maximum absorption at 353.04 nm and this peak position reflects the band gap of particles and it is found to be 2.51 eV which was calculated using Tauc plot. X-Ray diffraction (XRD) reveals crystaline size to be 49.85 nm which was calculated using Williamson-Hall (W-H) plot method. Photocatalytic degradation of acetic acid, chloroacetic acid and trichloroacetic acid has been studied by volumetric method using NaOH solution. Photocatalytic degradation of chloroacetic acid and acetic acid follows first order kinetics. The photodegradation efficiency for Al<sub>2</sub>S<sub>3</sub>/MoS<sub>2</sub> nanocomposite was found to be ≈97.8%. A Taft linear free energy relationship is noted for the catalysed reaction with ρ* = 0.233 and indicating electron withdrawing groups enhance the rate. An isokinetic relation is observed with β = 358 K indicating that enthalpy factor controls the reaction rate. The result of this paper suggests the possibility of degradation of organic compounds, industrial effluants and toxic organic compounds by photodegradation process by ecofriendly Al<sub>2</sub>S<sub>3</sub>/ MoS<sub>2</sub>. The antibacterial activity of Al<sub>2</sub>S<sub>3</sub>/MoS<sub>2</sub> nanocomposite was investigated. These particles were shown to have an effective bactericide.
