This study presents the successful synthesis of a novel Z-scheme heterojunction composite film consisting of Ag/Bi2MoO6/BiOBr through electrochemical processes and ionexchange techniques,followed by the photodep...This study presents the successful synthesis of a novel Z-scheme heterojunction composite film consisting of Ag/Bi2MoO6/BiOBr through electrochemical processes and ionexchange techniques,followed by the photodeposition of noble metal silver(Ag)onto the composite structure.The catalytic efficiency of semiconductor photocatalysts is greatly improved by utilizing the localized surface plasmon resonance(LSPR)effect observed in Ag nanoparticles(NPs).Furthermore,the noble metal Ag serves as an intermediary bridge facilitating charge transfer between Bi2MoO6and BiOBr,while the formation of a Schottky barrier effectively inhibits the recombination of photo-generated electron-hole pairs.As a result,the Ag-deposited Bi2MoO6/BiOBr film exhibits superior photocatalytic performance in the reduction of CO2compared to its unmodified counterpart.Our experimental results indicate a non-linear relationship between Ag deposition and the efficiency of photocatalytic CO2reduction to CO,characterized by an initial increase in efficiency followed by a decline.The optimized 1.5%-Ag/Bi2MoO6/BiOBr film demonstrates exceptional photocatalytic activity,attaining a CO production rate of 13.65μmol/(g·h).This research explores the fundamental mechanisms that lead to improved photocatalytic CO2reduction capabilities of the Ag/Bi2MoO6/BiOBr film.Our research offers important perspectives for the thoughtful design and production of highly efficient photocatalysts,which are essential for advancing sustainable energy solutions.展开更多
Silica nanosheets(SiO2 NSs) hold great promise for advanced thermal protection applications because of their exceptional thermal and chemical stability.However,their development has been hindered by challenges in s...Silica nanosheets(SiO2 NSs) hold great promise for advanced thermal protection applications because of their exceptional thermal and chemical stability.However,their development has been hindered by challenges in scalable synthesis and structural integration for specialized applications.Herein,we report a facile and scalable wet-chemical strategy for producing high-quality and ultrathin SiO2 NSs with lateral dimension more than 5 μm and thickness of ~2 nm.After graphene oxide(GO)-templated thermal treatment,the mechanical stiffness of the SiO2 NSs was significantly enhanced from 60.9 to 76.1 GPa.Leveraging their unique ultrathin and large lateral properties,the ultralight SiO2 NSs aerogel was achieved via a bidirectional freeze-casting technique.The aerogel demonstrates excellent fire resistance and high-temperature tolerance,maintaining its structure upon direct exposure to 1200℃ flames.Furthermore,the integration of SiO2 NSs into a polycaprolactone(PCL) matrix has enabled the development of a large-area and flexible fire-retardant composite film,which exhibits an exceptional flame selfextinguishing time of 2 s and mechanical flexibility.This work offers a scalable platform for fabricating functional SiO2 NSsbased materials and paves the way for their potential application in energy devices,aerospace protection,and flexible electronics.展开更多
To mitigate secondary electromagnetic pollution,there is an urgent need to develop absorption-dominant electromagnetic interference(EMI)shielding materials with low density,reduced thickness,lightweight construction,f...To mitigate secondary electromagnetic pollution,there is an urgent need to develop absorption-dominant electromagnetic interference(EMI)shielding materials with low density,reduced thickness,lightweight construction,flexibility,exceptional mechanical strength,and superior electrothermal and photothermal properties,particularly for flexible and wearable electronics.In this regard,we designed an absorption-based composite film comprising carbon nanotubes(CNT)and α-Fe2O3,featuring a CNT layer sandwiched between twoα-Fe2O3layers on the upper and lower surfaces.This composite film was fabricated through an electrodeposition process followed by a thermal annealing procedure to achieve enhanced EMI shielding performance along with improved electrothermal and photothermal properties.The strategically designed sandwich structure allows the rough surface of the upper α-Fe2O3layer to not only improve the impedance mismatch between free space and the composite film,facilitating the penetration of incident electromagnetic(EM)waves into the film and promoting increased EM absorption rather than reflection,but also to enhance electrical conductivity,thereby improving electron mobility and density.Consequently,the average total shielding effectiveness(SE)of the CNT/Fe16-300 composite demonstrates remarkable EMI shielding effectiveness(EMI SE:56.8 dB).Furthermore,the alteration in the absorption-to-reflection ratio(A/R)signifies a transition in the EMI shielding mechanism from reflection(0.69 for the pristine CNT film)to absorption(1.86 for the CNT/Fe16-300)with the incremental deposition of α-Fe2O3nanoparticles.This work presents a feasible manufacturing approach for developing composite films with a sandwich structure that exhibits absorption-dominant EMI shielding capabilities,contributing to advancements in thermal management and multifunctional electromagnetic shielding applications.展开更多
Tetravalent tin(Sn4+)-based inorganic perovskite semiconductors like Cs2SnI6are expected to replace lead-based perovskite counterparts due to advantages such as structural stability and environmental friendli...Tetravalent tin(Sn4+)-based inorganic perovskite semiconductors like Cs2SnI6are expected to replace lead-based perovskite counterparts due to advantages such as structural stability and environmental friendliness.In this paper,we reported the dopant compensation effect in the component-dependent self-doped(111)-oriented Cs2SnI6thin films grown with pulsed laser deposition(PLD)at room temperature.The films were grown on(100)-SrTiO3(STO)substrates at room temperature by PLD.Hall results of the Cs2SnI6films with different components realizing by controlling the ratio of SnI4/CsI in the targets demonstrate a clear change of conductivity type from N-type to P-type,while the carrier concentration decreases from 1018 to 1013 and accordingly the film resistivity increases significantly from 3.8 to 2506Ωcm.The defect-relatedopticalfingerprints of Cs2SnI6films werealsoinvestigated withtemperature-dependent photoluminescence spectroscopy.At low temperatures of 10 K,the Cs2SnI6films exhibit donor-bound(D0X)and donor-acceptor pair(DAP)emission,respectively,due to the self-doping effect.These re-sults indicate that controlling the composition of the PLD target is a powerful way to tune the electrical properties of Cs2SnI6films for possible applications in solar cells or X-ray detectors.展开更多
Total dose effects and single event effects on radiation-hardened power vertical double-diffusion metal oxide semiconductor(VDMOS) devices with composite SiO2-Si3N4 film gates are investigated.The relationships amon...Total dose effects and single event effects on radiation-hardened power vertical double-diffusion metal oxide semiconductor(VDMOS) devices with composite SiO2-Si3N4 film gates are investigated.The relationships among the important electrical parameters of the samples with different thickness SiO2-Si3N4 films,such as threshold voltage,breakdown voltage,and on-state resistance in accumulated dose,are discussed.The total dose experiment results show that the breakdown voltage and the on-state resistance barely change with the accumulated dose.However,the relationships between the threshold voltages of the samples and the accumulated dose are more complex,and not only positively drift,but also negatively drift.At the end of the total dose experiment,we select the group of samples which have the smaller threshold voltage shift to carry out the single event effect studies.We find that the samples with appropriate thickness ratio SiO2-Si3N4 films have a good radiation-hardening ability.This method may be useful in solving both the SEGR and the total dose problems with the composite SiO2-Si3N4 films.展开更多
Co−TiO2 nanocomposite films were prepared via magnetron sputtering at various substrate temperatures.The films comprise Co particles dispersed in an amorphous TiO2 matrix and exhibit coexisting ferromagnetic and super...Co−TiO2 nanocomposite films were prepared via magnetron sputtering at various substrate temperatures.The films comprise Co particles dispersed in an amorphous TiO2 matrix and exhibit coexisting ferromagnetic and superparamagnetic properties.When the substrate temperature increases from room temperature to 400℃,Co particles gradually grow,and the degree of Co oxidation significantly decreases.Consequently,the saturation magnetization increases from 0.13 to 0.43 T at the same Co content by increasing the substrate temperature from room temperature to 400℃.At a high substrate temperature,conductive pathways form among some of the clustered Co particles.Thus,resistivity rapidly declines from 1600 to 76μΩ·m.The magnetoresistive characteristic of Co−TiO2 films is achieved even at resistivity of as low as 76μΩ·m.These results reveal that the obtained nanocomposite films have low Co oxidation,high magnetization and magnetoresistance at room temperature.展开更多
This paper reports that single-layer and graded Au-TiO2 granular composite films with Au atom content 15%- 66% were prepared by using reactive co-sputtering technique. The third-order optical nonlinearity of single-la...This paper reports that single-layer and graded Au-TiO2 granular composite films with Au atom content 15%- 66% were prepared by using reactive co-sputtering technique. The third-order optical nonlinearity of single-layer and graded composite films was investigated by using s- and p-polarized Z-scans in femtosecond time scale. The nonlinear absorption coefficient βeff of single-layer Au-TiO2 films is measured to be -2.3×10^3-0.76×10^3 cm/GW with Au atom content 15%-66%. The βeff value of the 10-layer Au-TiO2 graded film is enhanced to be -2.1×10^4cm/GW calculated from p-polarized Z-scans, which is about ten times the maximum βeff of single-layer films. Broadened response in the wavelength region 730-860 nm of the enhanced optical nonlinearity of graded Au-TiO2 composite films was also investigated.展开更多
The TiO2-Co-TiO2 sandwich films were successfully grown on glass and silicon substrata making alternate use of radio frequency reactive magnetron sputtering and direct current magnetron sputtering. The structures and ...The TiO2-Co-TiO2 sandwich films were successfully grown on glass and silicon substrata making alternate use of radio frequency reactive magnetron sputtering and direct current magnetron sputtering. The structures and properties of these films were identified with X-ray diffraction (XRD), Raman spectra and X-ray photoemission spectra (XPS). It is shown that the sandwich film consists of two anatase TiO2 films with an embedded Co nano-film. The fact that, when the Co nano-film thickens, varied red shifts appear in optical absorption spectra may well be explained by the quantum confinement and tunnel effects. As for magnetic properties, the saturation magnetization, remnant magnetic induction and coercivity vary with the thickness of the Co nano-films. Moreover, the Co nano-film has a critical thickness of about 8.6 mn, which makes the coercivity of the composite film reach the maximum of about 1413 Oe.展开更多
Bi2WO6 nanoplate/TiO2 nanowire and Bi2WO6 nanoflower/TiO2 nanowire composite films were successfully prepared using a hydrothermal method.The results show that the light absorption for Bi2WO6/T...Bi2WO6 nanoplate/TiO2 nanowire and Bi2WO6 nanoflower/TiO2 nanowire composite films were successfully prepared using a hydrothermal method.The results show that the light absorption for Bi2WO6/TiO2 composite films is extended to the visible region after Bi2WO6 nanoplates and nanoflowers are assembled onto TiO2 nanowires.Furthermore,Bi2WO6 nanoflower/TiO2 nano wire composite film exhibits a better absorption property compared to Bi2WO6 nanoplate/TiO2 nanowire film,which is mainly ascribed to the narrower bandgap of Bi2WO6 nanoflower compared to that of Bi2WO6 nanoplate.The photocurrent density for Bi2WO6 nanoflower/TiO2 nanowire and Bi2WO6 nanoplate/TiO2 nanowire composite films can reach 95 and 62.5 μA cm-2,respectively,which are much higher than that obtained for a pure TiO2 nanowire film(25 μA cm-2).Meanwhile,under illumination,the pure TiO2 nanowire,Bi2WO6 nanoplate/TiO2 nanowire and Bi2WO6 nanoflower/TiO2 nanowire films can reduce the potential of the coupled 304 stainless steel in 3.5 wt.%NaCl solution by 299,719 and 739 mV,respectively.Thus,Bi2WO6 nanoflower/TiO2 nanowire film is found to provide the best effective photocathodic protection for 304 stainless steel.This work not only provides an example of shape-dependent photocathodic protection based on Bi2WO6 but also opens up new possibilities to design an ideal microstructure on the basis of semiconductor materials for future applications of photocathodic protection.展开更多
In this work,flexible photothermal PVA/Ti2O3 composite films with different amount(0 wt%,5 wt%,10 wt%,15 wt%)of Ti2O3 particles modified by steric acid were prepared by a simple solution casting method.The...In this work,flexible photothermal PVA/Ti2O3 composite films with different amount(0 wt%,5 wt%,10 wt%,15 wt%)of Ti2O3 particles modified by steric acid were prepared by a simple solution casting method.The microstructures,XRD patterns,FTIR spectra,UV-Vis-NIR spectra thermo-conductivity,thermo-stability and photothermal effects of these composite films were all characterized.These results indicated that Ti2O3 particles were well dispersed throughout the polyvinyl alcohol(PVA)matrix in the PVA/Ti2O3 composite films.And Ti2O3 particles could also effectively improve the photothermal properties of the composite films which exhibited high light absorption and generated a high temperature(about 57.4℃for film with 15 wt%Ti2O3 amount)on the surface when it was irradiated by a simulated sunlight source(1 kW/m2).展开更多
Cu2O/TiOa/Pt three-layer films were deposited on glass substrates using magnetron sputtering method. The surface morphology and the optical properties of the composite film were characterized by X-ray diffraction (XR...Cu2O/TiOa/Pt three-layer films were deposited on glass substrates using magnetron sputtering method. The surface morphology and the optical properties of the composite film were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet- visible spectroscopy (UV-Vis) and photoluminescence spectroscopy (PL). The photocatalytic activity of the samples was evaluated by the photocatalytic degradation of methyl orange (MO) aqueous solution under visible light irradiation. The results indicate that the Cu2O/TiO2/Pt composite films are made up of three layers which are Pt layer, anatase-TiO2 layer and Cu2O layer from bottom to top. The surface of the films is even and composed of regular-shaped spherical particles. The photocatalytic activity of the Cu2O/TiO2/Pt three-layer film is much higher than that of the Cu2O/TiO2 double-layer film. Such enhancement is ascribed to the presence of Pt layer, which further inhibits the photogenerated electron-hole recombination, prolongs the lifetime of the photogenerated carriers, increases the quantum efficiency and hence improves the photocatalytic activity of the film effectively.展开更多
In this work, CaF_2:Ln3+(Ln:Er,Er/Yb)/Nafion composite films were prepared using Nafion as modifications and matrices by dripping method. The composite films were characterized by Fourier transform infrared spectro...In this work, CaF_2:Ln3+(Ln:Er,Er/Yb)/Nafion composite films were prepared using Nafion as modifications and matrices by dripping method. The composite films were characterized by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD) and scanning electron microscopy(SEM). Composite films are transparent and CaF_2:Ln3+(Ln:Er,Er/Yb) nanoparticles are well dispersed in Nafion films.The thicknesses of CaF_2:Er3+/Nafion and CaF_2:Er3+,Yb3+/Nafion composite film are about 77 and 73 μm,respectively. The nanoparticles in composite film possess cubic phase. CaF_2:Er3+,Yb3+/Nafion composite film has stronger characteristic emission of Er3+ around 1530 nm with full width at half-maximum(FWHM) of 73 nm and longer luminescence lifetimes of 22.04 μs(25.03%) and 100.77 μs(74.97%).展开更多
Titanium dioxide (TiO2) loaded tungsten trioxide (WO3) composite films are prepared by an E-beam vapor system. Associated with the existence of a heterojunction at the interface of TiO2 and WO3, the prepared TiO2-...Titanium dioxide (TiO2) loaded tungsten trioxide (WO3) composite films are prepared by an E-beam vapor system. Associated with the existence of a heterojunction at the interface of TiO2 and WO3, the prepared TiO2-WO3 composite film shows enhanced photocurrent density, four times than the pure WO3 film illuminated under xenon lamp, and higher incident-photon-to-current conversion e^ciency. By varying the initial TiO2 film thickness, such composite structures could be optimized to obtain the highest photocurrent density. We believe that thin TiO2 films improve the light response and increase the surface roughness of WO3 films. Furthermore, the existence of the heterojunction results in the e^cient charge carriers' separation, transfer process, and a lower recombination of electron-hole pairs, which is beneficial for the enhancement of photocurrent density.展开更多
ZrO2/TiO2 composite photocatalytic film was produced on the pure titanium substrate using in-situ Zr(OH)4 colloidal particle by the micro-arc oxidation technique and characterized by scanning electron microscope (...ZrO2/TiO2 composite photocatalytic film was produced on the pure titanium substrate using in-situ Zr(OH)4 colloidal particle by the micro-arc oxidation technique and characterized by scanning electron microscope (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and ultraviolet-visible (UV-Vis) spectrophotometer. The composite film shows a lamellar and porous structure which consists of anatase, futile and ZrO2 phases. The optical absorption edge of film is shifted to longer wavelength when ZrO2 is introduced to TiO2. Furthermore, the photocatalytic reaction rate constants of degradation of rhodamine B solution with ZrO2/TiO2 composite film and pure TiO2 film under ultraviolet irradiation are measured as 0.0442 and 0.0186 h 1, respectively.展开更多
A SiC/ZrSiO4?SiO2 (SZS) coating was successfully fabricated on the carbon/carbon (C/C) composites by pack cementation, slurry painting and sintering to improve the anti-oxidation property and thermal shock resist...A SiC/ZrSiO4?SiO2 (SZS) coating was successfully fabricated on the carbon/carbon (C/C) composites by pack cementation, slurry painting and sintering to improve the anti-oxidation property and thermal shock resistance. The anti-oxidation properties under different oxygen partial pressures (OPP) and thermal shock resistance of the SZS coating were investigated. The results show that the SZS coated sample under low OPP, corresponding to the ambient air, during isothermal oxidation was 0.54% in mass gain after 111 h oxidation at 1500 ° C and less than 0.03% in mass loss after 50 h oxidation in high OPP, corresponding to the air flow rate of 36 L/h. Additionally, the residual compressive strengths (RCS) of the SZS coated samples after oxidation for 50 h in high OPP and 80 h in low OPP remain about 70% and 72.5% of those of original C/C samples, respectively. Moreover, the mass loss of SZS coated samples subjected to the thermal cycle from 1500 ° C in high OPP to boiling water for 30 times was merely 1.61%.展开更多
The Ni-P/TiO2 composite film on sintered NdFeB permanent magnet was investigated by X-ray diffraction (XRD),environmental scanning electron microscopy (ESEM),and energy dispersive X-ray spectrometer (EDX). The c...The Ni-P/TiO2 composite film on sintered NdFeB permanent magnet was investigated by X-ray diffraction (XRD),environmental scanning electron microscopy (ESEM),and energy dispersive X-ray spectrometer (EDX). The corrosion resistance of Ni-P/TiO2 film coated on NdFeB magnet,in 0.5 mol/L NaCl solution,was studied by potentiodynamic polarization,salt spray test and electrochemical impedance spectroscopy (EIS) techniques. The self-corrosion current density (icorr) and the polarization resistance (Rp) of Ni-P/TiO2 film are 0.22 μA/cm2 (about 14% of that of Ni-P coating),and 120 kΩ·cm2 (about 2 times of that of Ni-P coating),respectively. The anti-salt spray time of Ni-P/TiO2 film is about 2.5 times of that of the Ni-P coating. The results indicate that Ni-P/TiO2 film has a better corrosion resistance than Ni-P coating,and the composite film increases the corrosion resistance of NdFeB magnet markedly.展开更多
A NiP/TiO2 composite film on carbon steel was prepared by electroless plating and sol-gel composite process. An artificial neural network was applied to optimize the prepared condition of the composite film. Corrosion...A NiP/TiO2 composite film on carbon steel was prepared by electroless plating and sol-gel composite process. An artificial neural network was applied to optimize the prepared condition of the composite film. Corrosion behavior of the NiP/TiO2 composite film was investigated by polarization resistance measurement, anode polarization, ESEM (environmental scanning electron microscopy) and EIS (electrochemical impedance spectroscopy) measurements. Results showed that the NiP/ TiO2 composite film has a good corrosion resistance in 0.5mol/L H2SO4 solution. The element valence of the composite film was characterized by XPS (X-ray photoelectron spectroscopy) spectrum, and an anticorrosion mechanism of the composite film was discussed.展开更多
In this work, TiO2/Ti composite films were fabricated by 2-setp MCT and the following high temperature oxidation. Antibacterial activity of the composite films treated by ultrasonic cleaning to increase the performanc...In this work, TiO2/Ti composite films were fabricated by 2-setp MCT and the following high temperature oxidation. Antibacterial activity of the composite films treated by ultrasonic cleaning to increase the performance reliability was examined. The prepared TiO2/Ti composite films showed high photocatalytic activity in the degradation of methylene blue solution. It is obvious that? TiO2/Ti composite films have antibacterial activity under UV irradiation.展开更多
Series of TiO 2-ZnO heterojunction composite films with different n(Zn)(Ti) ratios were prepared by UDP450 magnetron sputter ion plating equipment, and the mole ratio of Zn to Ti was controlled by adjusting the cu...Series of TiO 2-ZnO heterojunction composite films with different n(Zn)(Ti) ratios were prepared by UDP450 magnetron sputter ion plating equipment, and the mole ratio of Zn to Ti was controlled by adjusting the current values of sputtering target. The effects of n(Zn)(Ti) on the microstructures of TiO2-ZnO films were investigated by SEM, AFM, Raman and XPS, and their photocatalytic decomposition of methyl orange solutions was evaluated. The results show that an increase in n(Zn)(Ti) typically results in a decrease in the grain size of composite films firstly and then an increase of grain size, while an increase in n(Zn)(Ti) leads to an increase in film roughness firstly and then a decrease in film roughness. Both grain size and roughness of TiO2-ZnO films reach the maximum and minimum at n(Zn)(Ti) of 1/9.3, respectively. The n(Zn)(Ti) shows little effect on the valences of Zn and Ti elements, which mainly exist in the form of TiO2 and ZnO phases. The n(Zn)(Ti) has influence on the amount of anataseutile TiO2 heterojunction in the film. With increase of the n(Zn)(Ti), the absorption intensity of the composite film increases and the absorption region extends to 450 nm, which is redshifted as much as 150 nm in comparison with the pure TiO2 films. However, the photocatalytic abilities of heterogeneous composite films do not depend on the n(Zn)(Ti) but rather on the microstructures of the TiO2-ZnO composite films. Degradation rate of the film reaches the maximum and the photocatalytic decomposition of pollutants works best when n(Zn)(Ti)=1:9.3.展开更多
In order to improve the corrosion resistance and biocompatibility of NiTi surgical alloy, TiO2 and TiO2-SiO2 thin films were prepared by sol-gel method. The surface characteristics of the film, which include surface c...In order to improve the corrosion resistance and biocompatibility of NiTi surgical alloy, TiO2 and TiO2-SiO2 thin films were prepared by sol-gel method. The surface characteristics of the film, which include surface composition, microstructure and surface morphology, were studied by X-ray diffraction (XRD), atomic force microscopy (AFM) and X-ray photoelectron spectra (XPS), respectively. A scratching test was used to assess the interface adhesive strength between the film and substrate. The corrosion resistance of NiTi alloy coated with oxide films were studied by anodic polarization curves measurement in biological solution. Additionally, a preliminary study of the in vitro bioactivity of the films was conducted. The results indicated that TiO2 and TiO2-SiO2 (Ti/Si=4:1) films have higher electrochemical corrosion resistance and can be used as protective layers on NiTi alloy. In addition, TiO2-SiO2 composite films have better bioactivity than TiO2 film.展开更多
基金Supported by the National Natural Science Foundation of China(21978196)Natural Science Foundation of Shanxi Province(201801D211008,202403021211018)+1 种基金Shanxi Provincial Education Department(S202413597023)Jincheng High Efficiency Conversion and Utilization Technology Innovation Center of CO2 Energy and Biomass Energy。
摘要This study presents the successful synthesis of a novel Z-scheme heterojunction composite film consisting of Ag/Bi2MoO6/BiOBr through electrochemical processes and ionexchange techniques,followed by the photodeposition of noble metal silver(Ag)onto the composite structure.The catalytic efficiency of semiconductor photocatalysts is greatly improved by utilizing the localized surface plasmon resonance(LSPR)effect observed in Ag nanoparticles(NPs).Furthermore,the noble metal Ag serves as an intermediary bridge facilitating charge transfer between Bi2MoO6and BiOBr,while the formation of a Schottky barrier effectively inhibits the recombination of photo-generated electron-hole pairs.As a result,the Ag-deposited Bi2MoO6/BiOBr film exhibits superior photocatalytic performance in the reduction of CO2compared to its unmodified counterpart.Our experimental results indicate a non-linear relationship between Ag deposition and the efficiency of photocatalytic CO2reduction to CO,characterized by an initial increase in efficiency followed by a decline.The optimized 1.5%-Ag/Bi2MoO6/BiOBr film demonstrates exceptional photocatalytic activity,attaining a CO production rate of 13.65μmol/(g·h).This research explores the fundamental mechanisms that lead to improved photocatalytic CO2reduction capabilities of the Ag/Bi2MoO6/BiOBr film.Our research offers important perspectives for the thoughtful design and production of highly efficient photocatalysts,which are essential for advancing sustainable energy solutions.
基金financially supported by the National Key R&D Program of China(Grant No.2022YFB25020000)the National Natural Science Foundation of China(Grant No.52471223)the Science and Technology Commission of Shanghai Municipality(Grant No.23160714000)。
摘要Silica nanosheets(SiO2 NSs) hold great promise for advanced thermal protection applications because of their exceptional thermal and chemical stability.However,their development has been hindered by challenges in scalable synthesis and structural integration for specialized applications.Herein,we report a facile and scalable wet-chemical strategy for producing high-quality and ultrathin SiO2 NSs with lateral dimension more than 5 μm and thickness of ~2 nm.After graphene oxide(GO)-templated thermal treatment,the mechanical stiffness of the SiO2 NSs was significantly enhanced from 60.9 to 76.1 GPa.Leveraging their unique ultrathin and large lateral properties,the ultralight SiO2 NSs aerogel was achieved via a bidirectional freeze-casting technique.The aerogel demonstrates excellent fire resistance and high-temperature tolerance,maintaining its structure upon direct exposure to 1200℃ flames.Furthermore,the integration of SiO2 NSs into a polycaprolactone(PCL) matrix has enabled the development of a large-area and flexible fire-retardant composite film,which exhibits an exceptional flame selfextinguishing time of 2 s and mechanical flexibility.This work offers a scalable platform for fabricating functional SiO2 NSsbased materials and paves the way for their potential application in energy devices,aerospace protection,and flexible electronics.
基金financially supported by the National Natural Science Foundation of China(Nos.52222202 and 51772310)Chinese Academy of Sciences Key Research Program of Frontier Sciences(No.QYZDY-SSWJSC031)Shanghai Pilot Program for Basic Research-Chinese Academy of Science,Shanghai Branch(No.JCYJ-SHFY-2021-001).
摘要To mitigate secondary electromagnetic pollution,there is an urgent need to develop absorption-dominant electromagnetic interference(EMI)shielding materials with low density,reduced thickness,lightweight construction,flexibility,exceptional mechanical strength,and superior electrothermal and photothermal properties,particularly for flexible and wearable electronics.In this regard,we designed an absorption-based composite film comprising carbon nanotubes(CNT)and α-Fe2O3,featuring a CNT layer sandwiched between twoα-Fe2O3layers on the upper and lower surfaces.This composite film was fabricated through an electrodeposition process followed by a thermal annealing procedure to achieve enhanced EMI shielding performance along with improved electrothermal and photothermal properties.The strategically designed sandwich structure allows the rough surface of the upper α-Fe2O3layer to not only improve the impedance mismatch between free space and the composite film,facilitating the penetration of incident electromagnetic(EM)waves into the film and promoting increased EM absorption rather than reflection,but also to enhance electrical conductivity,thereby improving electron mobility and density.Consequently,the average total shielding effectiveness(SE)of the CNT/Fe16-300 composite demonstrates remarkable EMI shielding effectiveness(EMI SE:56.8 dB).Furthermore,the alteration in the absorption-to-reflection ratio(A/R)signifies a transition in the EMI shielding mechanism from reflection(0.69 for the pristine CNT film)to absorption(1.86 for the CNT/Fe16-300)with the incremental deposition of α-Fe2O3nanoparticles.This work presents a feasible manufacturing approach for developing composite films with a sandwich structure that exhibits absorption-dominant EMI shielding capabilities,contributing to advancements in thermal management and multifunctional electromagnetic shielding applications.
基金financially supported by the National Key Re-search and Development Program of China(No.2022YFC3700801)the Key R&D Program of Shandong Province,China(No.2024SFGC0102),the Jinan Bureau of Education(No.JNSX2023015)the Jinan Bureau of Science and Technology(No.202333042).
摘要Tetravalent tin(Sn4+)-based inorganic perovskite semiconductors like Cs2SnI6are expected to replace lead-based perovskite counterparts due to advantages such as structural stability and environmental friendliness.In this paper,we reported the dopant compensation effect in the component-dependent self-doped(111)-oriented Cs2SnI6thin films grown with pulsed laser deposition(PLD)at room temperature.The films were grown on(100)-SrTiO3(STO)substrates at room temperature by PLD.Hall results of the Cs2SnI6films with different components realizing by controlling the ratio of SnI4/CsI in the targets demonstrate a clear change of conductivity type from N-type to P-type,while the carrier concentration decreases from 1018 to 1013 and accordingly the film resistivity increases significantly from 3.8 to 2506Ωcm.The defect-relatedopticalfingerprints of Cs2SnI6films werealsoinvestigated withtemperature-dependent photoluminescence spectroscopy.At low temperatures of 10 K,the Cs2SnI6films exhibit donor-bound(D0X)and donor-acceptor pair(DAP)emission,respectively,due to the self-doping effect.These re-sults indicate that controlling the composition of the PLD target is a powerful way to tune the electrical properties of Cs2SnI6films for possible applications in solar cells or X-ray detectors.
摘要Total dose effects and single event effects on radiation-hardened power vertical double-diffusion metal oxide semiconductor(VDMOS) devices with composite SiO2-Si3N4 film gates are investigated.The relationships among the important electrical parameters of the samples with different thickness SiO2-Si3N4 films,such as threshold voltage,breakdown voltage,and on-state resistance in accumulated dose,are discussed.The total dose experiment results show that the breakdown voltage and the on-state resistance barely change with the accumulated dose.However,the relationships between the threshold voltages of the samples and the accumulated dose are more complex,and not only positively drift,but also negatively drift.At the end of the total dose experiment,we select the group of samples which have the smaller threshold voltage shift to carry out the single event effect studies.We find that the samples with appropriate thickness ratio SiO2-Si3N4 films have a good radiation-hardening ability.This method may be useful in solving both the SEGR and the total dose problems with the composite SiO2-Si3N4 films.
基金Project(2016YFE0205700)supported by the National Key Research and Development Program of ChinaProject(18JCYBJC18000)supported by the Natural Science Foundation of Tianjin City,China。
摘要Co−TiO2 nanocomposite films were prepared via magnetron sputtering at various substrate temperatures.The films comprise Co particles dispersed in an amorphous TiO2 matrix and exhibit coexisting ferromagnetic and superparamagnetic properties.When the substrate temperature increases from room temperature to 400℃,Co particles gradually grow,and the degree of Co oxidation significantly decreases.Consequently,the saturation magnetization increases from 0.13 to 0.43 T at the same Co content by increasing the substrate temperature from room temperature to 400℃.At a high substrate temperature,conductive pathways form among some of the clustered Co particles.Thus,resistivity rapidly declines from 1600 to 76μΩ·m.The magnetoresistive characteristic of Co−TiO2 films is achieved even at resistivity of as low as 76μΩ·m.These results reveal that the obtained nanocomposite films have low Co oxidation,high magnetization and magnetoresistance at room temperature.
基金Project supported by the National Natural Science Foundation of China (Grant No 10474075)
摘要This paper reports that single-layer and graded Au-TiO2 granular composite films with Au atom content 15%- 66% were prepared by using reactive co-sputtering technique. The third-order optical nonlinearity of single-layer and graded composite films was investigated by using s- and p-polarized Z-scans in femtosecond time scale. The nonlinear absorption coefficient βeff of single-layer Au-TiO2 films is measured to be -2.3×10^3-0.76×10^3 cm/GW with Au atom content 15%-66%. The βeff value of the 10-layer Au-TiO2 graded film is enhanced to be -2.1×10^4cm/GW calculated from p-polarized Z-scans, which is about ten times the maximum βeff of single-layer films. Broadened response in the wavelength region 730-860 nm of the enhanced optical nonlinearity of graded Au-TiO2 composite films was also investigated.
基金Aeronautical Science Foundation of China (03G51069)Items of Engineering Research Institute, Peking University (ERIPKU-204031)
摘要The TiO2-Co-TiO2 sandwich films were successfully grown on glass and silicon substrata making alternate use of radio frequency reactive magnetron sputtering and direct current magnetron sputtering. The structures and properties of these films were identified with X-ray diffraction (XRD), Raman spectra and X-ray photoemission spectra (XPS). It is shown that the sandwich film consists of two anatase TiO2 films with an embedded Co nano-film. The fact that, when the Co nano-film thickens, varied red shifts appear in optical absorption spectra may well be explained by the quantum confinement and tunnel effects. As for magnetic properties, the saturation magnetization, remnant magnetic induction and coercivity vary with the thickness of the Co nano-films. Moreover, the Co nano-film has a critical thickness of about 8.6 mn, which makes the coercivity of the composite film reach the maximum of about 1413 Oe.
基金supported by the National Natural Science Foundation of China(Nos.51822402,51671044 and 52001051)the National Key Research and Development Program of China(Nos.2019YFA0209901 and 2018YFA0702901)+4 种基金the fund of the State Key Laboratory of Solidification Processing in NWPU(Grant No.SKLSP201902)the Liao Ning Revitalization Talents Program(XLYC1807047)the National MCF Energy R&D Program(No.2018YFE0312400)the Fund of Science and Technology on Reactor Fuel and Materials Laboratory(STRFML-2020-04)the China Postdoctoral Science Foundation(No.2020M670747).
摘要Bi2WO6 nanoplate/TiO2 nanowire and Bi2WO6 nanoflower/TiO2 nanowire composite films were successfully prepared using a hydrothermal method.The results show that the light absorption for Bi2WO6/TiO2 composite films is extended to the visible region after Bi2WO6 nanoplates and nanoflowers are assembled onto TiO2 nanowires.Furthermore,Bi2WO6 nanoflower/TiO2 nano wire composite film exhibits a better absorption property compared to Bi2WO6 nanoplate/TiO2 nanowire film,which is mainly ascribed to the narrower bandgap of Bi2WO6 nanoflower compared to that of Bi2WO6 nanoplate.The photocurrent density for Bi2WO6 nanoflower/TiO2 nanowire and Bi2WO6 nanoplate/TiO2 nanowire composite films can reach 95 and 62.5 μA cm-2,respectively,which are much higher than that obtained for a pure TiO2 nanowire film(25 μA cm-2).Meanwhile,under illumination,the pure TiO2 nanowire,Bi2WO6 nanoplate/TiO2 nanowire and Bi2WO6 nanoflower/TiO2 nanowire films can reduce the potential of the coupled 304 stainless steel in 3.5 wt.%NaCl solution by 299,719 and 739 mV,respectively.Thus,Bi2WO6 nanoflower/TiO2 nanowire film is found to provide the best effective photocathodic protection for 304 stainless steel.This work not only provides an example of shape-dependent photocathodic protection based on Bi2WO6 but also opens up new possibilities to design an ideal microstructure on the basis of semiconductor materials for future applications of photocathodic protection.
基金Funded by the Youth Backbone Teacher Training Plan in University of Henan Province(No.21220028)Science and Technology Research Project of Henan Province(No.242102321066)+2 种基金Natural Science Foundation of Henan Province(No.232300420312)Henan University of Technology Young Backbone Teacher Training Plan(No.21421260)the Innovation Training Program for College Students in Henan Province(No.202310463046)。
摘要In this work,flexible photothermal PVA/Ti2O3 composite films with different amount(0 wt%,5 wt%,10 wt%,15 wt%)of Ti2O3 particles modified by steric acid were prepared by a simple solution casting method.The microstructures,XRD patterns,FTIR spectra,UV-Vis-NIR spectra thermo-conductivity,thermo-stability and photothermal effects of these composite films were all characterized.These results indicated that Ti2O3 particles were well dispersed throughout the polyvinyl alcohol(PVA)matrix in the PVA/Ti2O3 composite films.And Ti2O3 particles could also effectively improve the photothermal properties of the composite films which exhibited high light absorption and generated a high temperature(about 57.4℃for film with 15 wt%Ti2O3 amount)on the surface when it was irradiated by a simulated sunlight source(1 kW/m2).
基金financially supported by the National Natural Science Foundation of China (No.51301118)the Projects of International Cooperation in Shanxi (No.2014081002)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi (No.2013108)
摘要Cu2O/TiOa/Pt three-layer films were deposited on glass substrates using magnetron sputtering method. The surface morphology and the optical properties of the composite film were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet- visible spectroscopy (UV-Vis) and photoluminescence spectroscopy (PL). The photocatalytic activity of the samples was evaluated by the photocatalytic degradation of methyl orange (MO) aqueous solution under visible light irradiation. The results indicate that the Cu2O/TiO2/Pt composite films are made up of three layers which are Pt layer, anatase-TiO2 layer and Cu2O layer from bottom to top. The surface of the films is even and composed of regular-shaped spherical particles. The photocatalytic activity of the Cu2O/TiO2/Pt three-layer film is much higher than that of the Cu2O/TiO2 double-layer film. Such enhancement is ascribed to the presence of Pt layer, which further inhibits the photogenerated electron-hole recombination, prolongs the lifetime of the photogenerated carriers, increases the quantum efficiency and hence improves the photocatalytic activity of the film effectively.
基金Project supported by Natural Science Basic Research Plan in Shaanxi Province of China(No.2018JM2021)Xi'an Science and Technology Plan Project(2016CXWL10,CXY1443WL21)Program of Education Department of Shaanxi Provincial Government(15JK2152)
摘要In this work, CaF_2:Ln3+(Ln:Er,Er/Yb)/Nafion composite films were prepared using Nafion as modifications and matrices by dripping method. The composite films were characterized by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD) and scanning electron microscopy(SEM). Composite films are transparent and CaF_2:Ln3+(Ln:Er,Er/Yb) nanoparticles are well dispersed in Nafion films.The thicknesses of CaF_2:Er3+/Nafion and CaF_2:Er3+,Yb3+/Nafion composite film are about 77 and 73 μm,respectively. The nanoparticles in composite film possess cubic phase. CaF_2:Er3+,Yb3+/Nafion composite film has stronger characteristic emission of Er3+ around 1530 nm with full width at half-maximum(FWHM) of 73 nm and longer luminescence lifetimes of 22.04 μs(25.03%) and 100.77 μs(74.97%).
基金Supported by the National Natural Science Foundation of China under Grant Nos 11174137,11474215 and 21204058the Natural Science Foundation for the Youth of Jiangsu Province under Grant No BK20130284the Priority Academic Program Development of Jiangsu Higher Education Institutions
摘要Titanium dioxide (TiO2) loaded tungsten trioxide (WO3) composite films are prepared by an E-beam vapor system. Associated with the existence of a heterojunction at the interface of TiO2 and WO3, the prepared TiO2-WO3 composite film shows enhanced photocurrent density, four times than the pure WO3 film illuminated under xenon lamp, and higher incident-photon-to-current conversion e^ciency. By varying the initial TiO2 film thickness, such composite structures could be optimized to obtain the highest photocurrent density. We believe that thin TiO2 films improve the light response and increase the surface roughness of WO3 films. Furthermore, the existence of the heterojunction results in the e^cient charge carriers' separation, transfer process, and a lower recombination of electron-hole pairs, which is beneficial for the enhancement of photocurrent density.
基金Project(gf200901002)supported by the Open Research Fund of National Defense Key Disciplines Laboratory of Light Alloy Processing Science and Technology of Nanchang Hangkong University,China
摘要ZrO2/TiO2 composite photocatalytic film was produced on the pure titanium substrate using in-situ Zr(OH)4 colloidal particle by the micro-arc oxidation technique and characterized by scanning electron microscope (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and ultraviolet-visible (UV-Vis) spectrophotometer. The composite film shows a lamellar and porous structure which consists of anatase, futile and ZrO2 phases. The optical absorption edge of film is shifted to longer wavelength when ZrO2 is introduced to TiO2. Furthermore, the photocatalytic reaction rate constants of degradation of rhodamine B solution with ZrO2/TiO2 composite film and pure TiO2 film under ultraviolet irradiation are measured as 0.0442 and 0.0186 h 1, respectively.
基金Project supported by the Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center,ChinaProject(51205417)supported by the National Natural Science Foundation of China
摘要A SiC/ZrSiO4?SiO2 (SZS) coating was successfully fabricated on the carbon/carbon (C/C) composites by pack cementation, slurry painting and sintering to improve the anti-oxidation property and thermal shock resistance. The anti-oxidation properties under different oxygen partial pressures (OPP) and thermal shock resistance of the SZS coating were investigated. The results show that the SZS coated sample under low OPP, corresponding to the ambient air, during isothermal oxidation was 0.54% in mass gain after 111 h oxidation at 1500 ° C and less than 0.03% in mass loss after 50 h oxidation in high OPP, corresponding to the air flow rate of 36 L/h. Additionally, the residual compressive strengths (RCS) of the SZS coated samples after oxidation for 50 h in high OPP and 80 h in low OPP remain about 70% and 72.5% of those of original C/C samples, respectively. Moreover, the mass loss of SZS coated samples subjected to the thermal cycle from 1500 ° C in high OPP to boiling water for 30 times was merely 1.61%.
基金Sponsored by Hi-Tech Research and Development Program of China (2003AA305120)
摘要The Ni-P/TiO2 composite film on sintered NdFeB permanent magnet was investigated by X-ray diffraction (XRD),environmental scanning electron microscopy (ESEM),and energy dispersive X-ray spectrometer (EDX). The corrosion resistance of Ni-P/TiO2 film coated on NdFeB magnet,in 0.5 mol/L NaCl solution,was studied by potentiodynamic polarization,salt spray test and electrochemical impedance spectroscopy (EIS) techniques. The self-corrosion current density (icorr) and the polarization resistance (Rp) of Ni-P/TiO2 film are 0.22 μA/cm2 (about 14% of that of Ni-P coating),and 120 kΩ·cm2 (about 2 times of that of Ni-P coating),respectively. The anti-salt spray time of Ni-P/TiO2 film is about 2.5 times of that of the Ni-P coating. The results indicate that Ni-P/TiO2 film has a better corrosion resistance than Ni-P coating,and the composite film increases the corrosion resistance of NdFeB magnet markedly.
摘要A NiP/TiO2 composite film on carbon steel was prepared by electroless plating and sol-gel composite process. An artificial neural network was applied to optimize the prepared condition of the composite film. Corrosion behavior of the NiP/TiO2 composite film was investigated by polarization resistance measurement, anode polarization, ESEM (environmental scanning electron microscopy) and EIS (electrochemical impedance spectroscopy) measurements. Results showed that the NiP/ TiO2 composite film has a good corrosion resistance in 0.5mol/L H2SO4 solution. The element valence of the composite film was characterized by XPS (X-ray photoelectron spectroscopy) spectrum, and an anticorrosion mechanism of the composite film was discussed.
摘要In this work, TiO2/Ti composite films were fabricated by 2-setp MCT and the following high temperature oxidation. Antibacterial activity of the composite films treated by ultrasonic cleaning to increase the performance reliability was examined. The prepared TiO2/Ti composite films showed high photocatalytic activity in the degradation of methylene blue solution. It is obvious that? TiO2/Ti composite films have antibacterial activity under UV irradiation.
基金Project (2010JQ6008) supported by the Natural Science Foundation of Shaanxi Province,China
摘要Series of TiO 2-ZnO heterojunction composite films with different n(Zn)(Ti) ratios were prepared by UDP450 magnetron sputter ion plating equipment, and the mole ratio of Zn to Ti was controlled by adjusting the current values of sputtering target. The effects of n(Zn)(Ti) on the microstructures of TiO2-ZnO films were investigated by SEM, AFM, Raman and XPS, and their photocatalytic decomposition of methyl orange solutions was evaluated. The results show that an increase in n(Zn)(Ti) typically results in a decrease in the grain size of composite films firstly and then an increase of grain size, while an increase in n(Zn)(Ti) leads to an increase in film roughness firstly and then a decrease in film roughness. Both grain size and roughness of TiO2-ZnO films reach the maximum and minimum at n(Zn)(Ti) of 1/9.3, respectively. The n(Zn)(Ti) shows little effect on the valences of Zn and Ti elements, which mainly exist in the form of TiO2 and ZnO phases. The n(Zn)(Ti) has influence on the amount of anataseutile TiO2 heterojunction in the film. With increase of the n(Zn)(Ti), the absorption intensity of the composite film increases and the absorption region extends to 450 nm, which is redshifted as much as 150 nm in comparison with the pure TiO2 films. However, the photocatalytic abilities of heterogeneous composite films do not depend on the n(Zn)(Ti) but rather on the microstructures of the TiO2-ZnO composite films. Degradation rate of the film reaches the maximum and the photocatalytic decomposition of pollutants works best when n(Zn)(Ti)=1:9.3.
基金This work was supported by the National Natural Science Foundation of China(No.50081001)the Education Department Project of Liaoning Province(No.202073425).
摘要In order to improve the corrosion resistance and biocompatibility of NiTi surgical alloy, TiO2 and TiO2-SiO2 thin films were prepared by sol-gel method. The surface characteristics of the film, which include surface composition, microstructure and surface morphology, were studied by X-ray diffraction (XRD), atomic force microscopy (AFM) and X-ray photoelectron spectra (XPS), respectively. A scratching test was used to assess the interface adhesive strength between the film and substrate. The corrosion resistance of NiTi alloy coated with oxide films were studied by anodic polarization curves measurement in biological solution. Additionally, a preliminary study of the in vitro bioactivity of the films was conducted. The results indicated that TiO2 and TiO2-SiO2 (Ti/Si=4:1) films have higher electrochemical corrosion resistance and can be used as protective layers on NiTi alloy. In addition, TiO2-SiO2 composite films have better bioactivity than TiO2 film.