A modified CuO/CeO2 catalyst was prepared by surfactant-assisted impregnation method and showed better catalytic activity for low temperature CO oxidation than that from conventional impregnation method. The physicoch...A modified CuO/CeO2 catalyst was prepared by surfactant-assisted impregnation method and showed better catalytic activity for low temperature CO oxidation than that from conventional impregnation method. The physicochemical properties of different CuO/CeO2 catalysts were characterized by thermogravimetrie and differential scanning calorimetric measurements (TG-DSC), X-ray diffraction (XRD), N2 adsorpti0n-desorption, Raman spectroscopy, H2 temperature-programmed reduction (H2-TPR), tern- perature-programmed desorption of 02 (O2-TPD), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The re- sults suggested that the addition of hexadecyl trimethyl ammonium bromide (CTAB) into the impregnation solution could improve the dispersion of CuO species, which could facilitate Cu2+ incorporating into CeO2 lattice and strengthened the synergistic effects between CuO and CeO2, making the lattice oxygen more active, and eventually resulting in enhanced activity for CO oxidation.展开更多
Utilizing lightweight Al alloys in various industrial applications requires achieving precise pressure tightness and leak requirements.Vacuum pressure impregnation(VPI)with thermosetting polymers is commonly used to a...Utilizing lightweight Al alloys in various industrial applications requires achieving precise pressure tightness and leak requirements.Vacuum pressure impregnation(VPI)with thermosetting polymers is commonly used to address leakage defects in die-cast Al alloys.In this study,the efficacy of the VPI technique in sealing alloy parts was investigated using a combination of nondestructive micro X-ray computed tomography(micro XCT)and a standard leak test.The results demonstrate that the commonly used water leak test is insufficient for determining the sealing performance.Instead,micro XCT shows distinct advantages by enabling more comprehensive analysis.It reveals the presence of a low atomic number impregnates sealant within casting defects,which has low grey contrast and allows for visualizing primary leakage paths in 3D.The effective atomic number of impregnated resin is 6.75 and that of Al alloy is 13.69 by dual-energy X-ray CT.This research findings will contribute to enhancing the standard VPI process parameters and the properties of impregnating sealants to improve quality assurance for impregnation in industrial metals.展开更多
In this study,a green and pollution-free multifunctional superhydrophobic paper-based material was prepared using a simple and efficient dipping method.The superhydrophobic paper with a water contact angle(WCA)of 160&...In this study,a green and pollution-free multifunctional superhydrophobic paper-based material was prepared using a simple and efficient dipping method.The superhydrophobic paper with a water contact angle(WCA)of 160°was prepared by attaching micro-and nanocomposite particles,made of stearic acid-modified chitosan and two kinds of titanium dioxide(TiO_(2))nanoparticles of different sizes,to a paper substrate.The surface morphology,elemental composition,and wetting properties of the coatings were examined using scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FT-IR),and contact angle measurements.Additionally,superhydrophobic coatings exhibited good self-cleaning properties,liquid repellency,ease of repair,and antifouling properties in organic solutions.展开更多
MoS_2 samples with controllable morphologies and structures were synthesized using surfactantassisted hydrothermal processes.The effects of surfactants(PEG,PVP,P123,SDS,AOT,and CTAB)on the morphologies and structure...MoS_2 samples with controllable morphologies and structures were synthesized using surfactantassisted hydrothermal processes.The effects of surfactants(PEG,PVP,P123,SDS,AOT,and CTAB)on the morphologies and structures of MoS_2 samples were investigated.The results revealed that spherical,bulk-like,and flower-like MoS_2 particles assembled by NH4~+-intercalated MoS_2 nano-sheets were synthesized.The morphologies of the MoS_2 samples and their structures(including the slab length and the number of stacked layers) of MoS_2 nano-sheets in these samples could be controlled by adjusting the surfactants.Mono-dispersed spherical MoS_2 particles could be synthesized with PEG via the creation of MoS_2 nano-sheets with slab lengths shorter than 15 nm and fewer than six stacked layers.Possible formation mechanisms of these MoS_2 samples created via surfactant-assisted hydrothermal processes are proposed.Further,the catalytic activities of MoS_2 samples for anthracene hydrogenation were evaluated in a slurry-bed reactor.The catalyst synthesized with the surfactant PEG exhibited the highest catalytic hydrogenation activity.Compared with the other catalysts,it had a smaller particle size,mono-dispersed spherical morphology,shorter slab length,and fewer stacked layers;these were all beneficial to exposing its active edges.This work provides an efficient approach to synthesize transition metal sulfides with controllable morphologies and structures.展开更多
A porous NiO/yttria-stabilized zirconia was prepared by gel casting technique. anode substrate for tubular solid oxide fuel cells Nano-scale samaria-doped ceria (SDC) particles were formed onto the anode substrate t...A porous NiO/yttria-stabilized zirconia was prepared by gel casting technique. anode substrate for tubular solid oxide fuel cells Nano-scale samaria-doped ceria (SDC) particles were formed onto the anode substrate to modify the anode microstructure by the impregnation of solution of Sm(NO3)3 and Ce(NO3)3. Electrochemical impedance spectroscopy, current-voltage and current-powder curves of the cells were measured using an electrochemical workstation. Scanning electron microcopy was used to observe the microstructure. The results indicate that the stability of the performance of the cell operated on humidified methane can be significantly improved by incorporating the nano-structured SDC particles, compared with the unmodified cell. This verifies that the coated SDC electrodes are very effective in suppressing catalytic carbon formation by blocking methane from approaching the Ni, which is catalytically active towards methane pyrolysis. In addition, it was found that a small amount of deposited carbon is beneficial to the performance of the anode. The cell showed a peak power density of 225 mW/cm^2 when it was fed with H2 fuel at 700 ℃, but the power density increased to 400 mW/cm^2 when the fuel was switched from hydrogen to methane at the same flow rate. Methane conversion achieved about 90%, measured by gas chromatogram with a 10.0 mL/min flow rate of fuel at 700 ℃. Although the carbon deposition was not suppressed absolutely, some deposited carbon was beneficial for performance improvement.展开更多
Silica-supported CuCo catalysts were prepared by impregnation method with different impregnation sequence for higher alcohols synthesis. These catalysts were characterized by H2-TPR, XRD, N2 adsorption, XPS techniques...Silica-supported CuCo catalysts were prepared by impregnation method with different impregnation sequence for higher alcohols synthesis. These catalysts were characterized by H2-TPR, XRD, N2 adsorption, XPS techniques and CO selective hydrogenation reaction measurement. The effects of impregnation sequence on the structure and performance of catalysts were investigated, and there were important influences on the selectivity to higher alcohols. There was a strong synergistic effect between copper and cobalt for the co-impregnated sample. The CuCo/SiO2 catalyst prepared by co- impregnation showed a better yield of total alcohols, and a higher selectivity to total alcohols which reached 51.5%.展开更多
High-pressure impregnation, a new preparation method for sorbents to remove H2S from hot coal gas, is introduced in this paper. Semi-coke (SC) and ZnO is selected as the support and active component of sorbent, resp...High-pressure impregnation, a new preparation method for sorbents to remove H2S from hot coal gas, is introduced in this paper. Semi-coke (SC) and ZnO is selected as the support and active component of sorbent, respectively. The sorbent preparation process includes high-pressure impregnation, filtration, ovendry and calcination. The aim of this research is to primarily study the effects of the impregnation pressure on physical properties and desulfurization ability of the sorbent. The desulfurization experiment was carried out in a fixed-bed reactor at 500 ~C and a simulated coal gas used in this work was composed of CO (33 vol%), H2 (39 vol%), H2S (300 ppm in volume), and N2 (balance). Experimental results show that the pore structure of the SC support can be improved effectively and ZnO active component can be uniformly dispersed on the support, with the small particle size of 10-500 nm. Sorbents prepared using high-pressure impregnation have better desulfurization capacity and their active components have higher utilization rate. P20-ZnSC sorbent, obtained by high-pressure impregnation at 20 atm, has the best desulfurization ability with a sulfur capacity of 7.54 g S/100g sorbent and a breakthrough time of 44 h. Its desulfurization precision and efficiency of removing H2S from the middle temperature gases can reach 〈 1 ppm and 〉99.7%, respectively, before sorbent breakthrough.展开更多
Zn-Mn-Cu/SC(U) sorbent was hydrothermally synthesized by ultrasound-assisted high-pressure impregnation method with semi-coke(SC)as support and the mixed solution of zinc nitrate,manganese nitrate and copper nitra...Zn-Mn-Cu/SC(U) sorbent was hydrothermally synthesized by ultrasound-assisted high-pressure impregnation method with semi-coke(SC)as support and the mixed solution of zinc nitrate,manganese nitrate and copper nitrate as active component precursors.The desulfurization performances of hot coal gas on the prepared sorbent at a mid-temperature of 500°C were tested in fixed-bed reactor.Morphology and pore structure of the prepared sorbent were also characterized by TEM,N2adsorption/desorption isotherms and XRD.For comparison,the sorbent of Zn-Mn-Cu/SC prepared by conventional high-pressure impregnation was also evaluated and characterized in order to study the effects of ultrasound treatment.Zn-Mn-Cu/SC(U) sorbent prepared by high-pressure impregnation under ultrasound-assisted condition showed a better desulfurization performance than Zn-Mn-Cu/SC.It could remove H2 S from 1000×10-6m3/m3 to 0.1×10-6m3/m3 at 500°C and maintained for 12.5 h with the sulfur capacity of 7.74%,in which both the breakthrough time and sulfur capacity were about 32% and 51% higher than those of Zn-Mn-Cu/SC sorbent.The introduction of ultrasound during high-pressure impregnation process greatly improved the morphology and pore structure of the sorbent.The ultrasonic treatment made particle size of active components smaller and made them more evenly disperse on semi-coke support,which provided more opportunities to contact with H2S in coal-based gases.However,there were no any difference in compositions and existing forms of active components on the Zn-Mn-Cu/SC and Zn-Mn-Cu/SC(U) sorbents.展开更多
Solid oxide fuel cell(SOFC) electrodes,after a high temperature sintering,may be impregnated to deposit nanoparticles within their pores to enhance the catalytic function.Samarium doped CeO2(SDC) nanoparticles were in...Solid oxide fuel cell(SOFC) electrodes,after a high temperature sintering,may be impregnated to deposit nanoparticles within their pores to enhance the catalytic function.Samarium doped CeO2(SDC) nanoparticles were infiltrated into(Pr0.7Ca0.3)0.9MnO3-δ(PCM) cathode of anode supported SOFC cells.The cell with 2.6 mg/cm2 SDC impregnated in cathode showed the maximum power density of 580 mW/cm2 compared with 310 mW/cm2 of the cell without impregnation at 850 °C.The cells were also characterized with the impeda...展开更多
The surface of as-prepared LiMn2O4 was modified with ZnO, Al2O3, CoO and LiCoO2 using a simple nitrate melting impregnation method. Transmission electron microscopy (TEM) studies indicated that oxide nano- particles...The surface of as-prepared LiMn2O4 was modified with ZnO, Al2O3, CoO and LiCoO2 using a simple nitrate melting impregnation method. Transmission electron microscopy (TEM) studies indicated that oxide nano- particles in the range of 10~50 nm are coated on the surface of the spinel. The surface modified samples show better capacity retention than the unmodified LiMn2O4 spinel at both room temperature and 55℃. Among these samples, the ZnO-modified LiMn2O4 shows the best combination of a high capacity and a low capacity fading rate of 0.036% per cycle at room temperature and 0.064% per cycle at 55℃. The improvement for surface modified LiMn2O4 can be attributed to the inhibition of Mn dissolution and O losses on the surface.展开更多
Supported metal catalysts play a vital role in the chemical industry, and the metal-support interaction is an important property of the catalyst. However, in the traditional impregnation method, it is difficult to obt...Supported metal catalysts play a vital role in the chemical industry, and the metal-support interaction is an important property of the catalyst. However, in the traditional impregnation method, it is difficult to obtain sufficient metal-support interactions owing to the mobility of the metal precursor during evaporation drying. Here, freeze drying is applied during impregnation instead of evaporation drying for enhancing the metal-support interactions. 57 Fe ZSM-5 was chosen as a representative catalyst. A quantitative analysis was conducted based on Mossbauer spectroscopy. Compared with traditional evaporation-drying catalyst, freeze-drying catalyst has stronger metal-support interactions. In addition, more iron species are confined in the channel and smaller metal sizes and less diversity are obtained. The compositional change is also proved because of the superior performance of the freeze-drying catalyst during N2O decomposition. This method can be extended to other supported metal catalysts prepared through an impregnation method, which can be used to tune the metal-support interactions and metal sizes.展开更多
Felt base carbon/carbon composites fabricated by super-high pressure impregnation carbonization process (SPIC) were heat treated at high temperature 2773K. The oxidation properties of felt base carbon/carbon composite...Felt base carbon/carbon composites fabricated by super-high pressure impregnation carbonization process (SPIC) were heat treated at high temperature 2773K. The oxidation properties of felt base carbon/carbon composites were investigated at different temperatures (773-1173K), and the microstructures of carbon/carbon composites were studied by SEM and X-ray diffraction. The experimental results showed that the inter-laminar distance of (002) plane (d002) deceased while the microcrystalline stack height (Lc) increased. The oxidation rate of felt base carbon/carbon composites was invari-able at certain temperatures. The oxidation mechanism of carbon/carbon composites changed remarkably at the oxidation temperature 973K. At the initial oxidation stage of carbon/carbon composites, carbon matrix was oxidized much more rapidly than carbon felt.展开更多
To enhance the photocatalytic activity of B-BiVO4,Ni-doped B?BiVO4photocatalyst(Ni-B-BiVO4)was synthesized through sol-gel and impregnation method.The photocatalysts were characterized by XPS,XRD,SEM,EDS,BET and UV-Vi...To enhance the photocatalytic activity of B-BiVO4,Ni-doped B?BiVO4photocatalyst(Ni-B-BiVO4)was synthesized through sol-gel and impregnation method.The photocatalysts were characterized by XPS,XRD,SEM,EDS,BET and UV-Vis DRS techniques.The results showed that single or double doping did not change the crystalline structure and morphology,but the particle size decreased with Ni doping.The band gap energy absorption edge of Ni-B-BiVO4shifted to a longer wavelength compared with undoped,B or Ni single doped BiVO4.More V4+and surface hydroxyl oxygen were observed in BiVO4after Ni-B co-doping.When the optimal mass fraction of Ni is0.30%,the degradation rate of MO in50min is95%for0.3Ni-B-BiVO4sample which also can effectively degrade methyl blue(MB),acid orange(AOII)II and rhodamine B(RhB).The enhanced photocatalytic activity is attributed to the synergistic effects of B and Ni doping.展开更多
Two types of small iron clusters supported on γ-Al2O3-RT(dehydroxylated at room temperature) and γ-Al2O3-800 (dehydroxylated at 800 ℃) were prepared by solvated metal atom impregnation (SMAI) techniques. The ...Two types of small iron clusters supported on γ-Al2O3-RT(dehydroxylated at room temperature) and γ-Al2O3-800 (dehydroxylated at 800 ℃) were prepared by solvated metal atom impregnation (SMAI) techniques. The iron atom precursor complex, bis(toluene)iron(0) formed in the metal atom reactor, was impregnated into γ-Al2O3 having different concentrations of surface hydroxyl groups to study the effect of surface hydroxylation on the crucial stage of iron cluster formation. Catalysts prepared in this way were characterized by TEM, Mǒssbauer, and chemisorption measurements, and the results show that higher concentration of surface hydroxyl groups of γ-Al2O3-RT favors the formation of more positively charged supported iron cluster Fen/γ-Al2O3-RT, and the lower concentration of surface hydroxyl groups of γ-Al2O3-800 favors the formation of basically neutral supported iron cluster Fen/γ-Al2O3-800. The measured results also indicate that the higher concentration of surface hydroxyl groups causes the rapid decomposition of precursor complex, bis(toluene)iron(0), and favors the formation of relatively large iron cluster. Consequently, these two types of catalysts show different catalytic properties in Fischer-Tropsch reaction. The catalytic pattern of Fen/γ-Al2O3-RT in F-T reaction is similar to that of the unreduced γ-Fe2O3 and that of Fen/γ-Al2O3-800 is similar to that of the reduced α-Fe2O3.展开更多
Two silica-supported cobalt catalysts were prepared by incipient wetness impregnation under atmospheric and vacuum conditions.N2 ph- ysisorption,H2 chemisorption,XRD,SEM,TEM,XPS and H2-TPR were used to characterize th...Two silica-supported cobalt catalysts were prepared by incipient wetness impregnation under atmospheric and vacuum conditions.N2 ph- ysisorption,H2 chemisorption,XRD,SEM,TEM,XPS and H2-TPR were used to characterize the catalysts.The results showed that the impregnation methods had an effect on the size,dispersion and reducibility of cobalt particles.Under vacuum conditions,cobalt-containing steeping liquor could penetrate into the inner pores of silica support and more bivalent cobalt oxides were formed in the Co3O4 crystallites.Furthermore,cobalt precursors were rarely inclined to agglomerate and the smaller cobalt particles were uniform on the support,which led to the higher activity of the Co/SiO2(B)catalyst than the normal one under the reaction conditions of 483- 523 K,1 - 2 MPa,gas hourly space velocity of 500–1000 h-1 and molar ratio of H2/CO=0.5 - 2.0.展开更多
An efficient technology of impregnation of carbonate crushed stone by oil-product based on SCF-impregnation process usage with propane/butane solvent was developed. Regular impregnation throughout the volume of crushe...An efficient technology of impregnation of carbonate crushed stone by oil-product based on SCF-impregnation process usage with propane/butane solvent was developed. Regular impregnation throughout the volume of crushed stone sample is achieved. As a result of the appliance of proposed technology, the humidity of the treated crushed stone samples decreased down to 0.54%.展开更多
In order to improve the properties of purging plugs and to prolong their service life,this work attempted to impregnate alumina-spinel castables for purging plugs in refining ladle with saturated magnesium chloride so...In order to improve the properties of purging plugs and to prolong their service life,this work attempted to impregnate alumina-spinel castables for purging plugs in refining ladle with saturated magnesium chloride solution under vacuum.After being impregnated for the first time,the specimens were treated in two different ways:(1)dried at 110℃for 24 h;(2)heated at 600℃for 3 h.Then they were impregnated for the second time.All specimens were heated at 1550℃for 3 h,then the cold properties and the high temperature properties were tested according to corresponding standards.Test results were compared and analyzed.The results show that:after being impregnated,the specimen have both better cold properties and high temperature properties,the microstructure analysis result proves that it is attributed to in situ formed spinel.However,because MgO produced by MgCl2-6H20 decomposing above 527℃can hydrate and destroy specimen microstructure,which can make the properties of specimens impregnated in the second way get worse.By comprehensive consideration,the first scheme way is more suitable.展开更多
A novel greener method to impregnate silver nanoparticles (AgNPs) into microcrystalline cellulose (MCC) by curry leaf (Murraya koenigii) extract mediated biological process is presented. The active reduction of silver...A novel greener method to impregnate silver nanoparticles (AgNPs) into microcrystalline cellulose (MCC) by curry leaf (Murraya koenigii) extract mediated biological process is presented. The active reduction of silver ions by curry leaf extract was explored for the in situ impregnation AgNPs into MCC. Transmission electron microscopy (TEM) analyses of MCC coated with AgNPs showed the formation of silver particle sizes in the range of 10-25 nm and have a spherical shape. Further the, EDS analysis of MCC/Ag nanocomposite confirms the formation of Ag structure on microcrystalline cellulose. Solvent casting of poly(lactic-acid) was used to produce composite films containing silver impregnated MCC aiming for antimicrobial applications.展开更多
In this paper, we deals with mechanical performance of resin impregnation with natural fiber and fiber reinforced composites. The effect of the addition of a rein impregnation process on static strength of the injecti...In this paper, we deals with mechanical performance of resin impregnation with natural fiber and fiber reinforced composites. The effect of the addition of a rein impregnation process on static strength of the injection molded composites was investigated by carrying out tensile and banding tests, followed by Scanning electron microscopy (SEM) observation of fiber surface and fracture surface of composites. The tensile strength of natural fiber and natural fiber reinforced composites with resin impregnation method increases with Polyvinyl alcohol (PVA) impregnation. In addition, Phenol resin impregnation recovers fiber tensile strength after alkali treatment. Resin impregnation causes decrease in contact surface area;however, it does not cause decrease in mechanical properties. Our results suggest that the using rein impregnation method has better effect on the mechanical properties of natural fiber reinforced Polypropylene (PP) composites.展开更多
基金supported by the National Natural Science Foundation of China(21273150)‘‘Shu Guang’’Project(10GG23)of Shanghai Municipal Education CommissionShanghai Education Development Foundation
文摘A modified CuO/CeO2 catalyst was prepared by surfactant-assisted impregnation method and showed better catalytic activity for low temperature CO oxidation than that from conventional impregnation method. The physicochemical properties of different CuO/CeO2 catalysts were characterized by thermogravimetrie and differential scanning calorimetric measurements (TG-DSC), X-ray diffraction (XRD), N2 adsorpti0n-desorption, Raman spectroscopy, H2 temperature-programmed reduction (H2-TPR), tern- perature-programmed desorption of 02 (O2-TPD), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The re- sults suggested that the addition of hexadecyl trimethyl ammonium bromide (CTAB) into the impregnation solution could improve the dispersion of CuO species, which could facilitate Cu2+ incorporating into CeO2 lattice and strengthened the synergistic effects between CuO and CeO2, making the lattice oxygen more active, and eventually resulting in enhanced activity for CO oxidation.
文摘Utilizing lightweight Al alloys in various industrial applications requires achieving precise pressure tightness and leak requirements.Vacuum pressure impregnation(VPI)with thermosetting polymers is commonly used to address leakage defects in die-cast Al alloys.In this study,the efficacy of the VPI technique in sealing alloy parts was investigated using a combination of nondestructive micro X-ray computed tomography(micro XCT)and a standard leak test.The results demonstrate that the commonly used water leak test is insufficient for determining the sealing performance.Instead,micro XCT shows distinct advantages by enabling more comprehensive analysis.It reveals the presence of a low atomic number impregnates sealant within casting defects,which has low grey contrast and allows for visualizing primary leakage paths in 3D.The effective atomic number of impregnated resin is 6.75 and that of Al alloy is 13.69 by dual-energy X-ray CT.This research findings will contribute to enhancing the standard VPI process parameters and the properties of impregnating sealants to improve quality assurance for impregnation in industrial metals.
基金the financial support from the Key Research and Development Project of Shandong Province (2019GHY112040)National Natural Science Foundation of China (22078167)+4 种基金Youth Innovative Team Development Plan of Colleges and Universities in Shandong Province (2019KJC008)Shandong Province Major Innovation Project (2018CXGC1001)Foundation (No. XWZR201901) of the State Key Laboratory of Bio-based Material and Green Papermaking, Qilu University of TechnologyMajor Innovation Project of Qingdao West Coast (2019-27)Shandong Province Key Supporting Areas for Introducing Urgently Needed and Shortage of Talents Project-Key Technology Research and Development and Industrialization of Highly Water-Resistant Biomass-Based Materials。
文摘In this study,a green and pollution-free multifunctional superhydrophobic paper-based material was prepared using a simple and efficient dipping method.The superhydrophobic paper with a water contact angle(WCA)of 160°was prepared by attaching micro-and nanocomposite particles,made of stearic acid-modified chitosan and two kinds of titanium dioxide(TiO_(2))nanoparticles of different sizes,to a paper substrate.The surface morphology,elemental composition,and wetting properties of the coatings were examined using scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FT-IR),and contact angle measurements.Additionally,superhydrophobic coatings exhibited good self-cleaning properties,liquid repellency,ease of repair,and antifouling properties in organic solutions.
基金supported by the National Natural Science Foundation of China(21303186)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA07020300)~~
文摘MoS_2 samples with controllable morphologies and structures were synthesized using surfactantassisted hydrothermal processes.The effects of surfactants(PEG,PVP,P123,SDS,AOT,and CTAB)on the morphologies and structures of MoS_2 samples were investigated.The results revealed that spherical,bulk-like,and flower-like MoS_2 particles assembled by NH4~+-intercalated MoS_2 nano-sheets were synthesized.The morphologies of the MoS_2 samples and their structures(including the slab length and the number of stacked layers) of MoS_2 nano-sheets in these samples could be controlled by adjusting the surfactants.Mono-dispersed spherical MoS_2 particles could be synthesized with PEG via the creation of MoS_2 nano-sheets with slab lengths shorter than 15 nm and fewer than six stacked layers.Possible formation mechanisms of these MoS_2 samples created via surfactant-assisted hydrothermal processes are proposed.Further,the catalytic activities of MoS_2 samples for anthracene hydrogenation were evaluated in a slurry-bed reactor.The catalyst synthesized with the surfactant PEG exhibited the highest catalytic hydrogenation activity.Compared with the other catalysts,it had a smaller particle size,mono-dispersed spherical morphology,shorter slab length,and fewer stacked layers;these were all beneficial to exposing its active edges.This work provides an efficient approach to synthesize transition metal sulfides with controllable morphologies and structures.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (No.20871110 and No.50730002). The authors express their appreciation to Xin-bo Lii, Qingdao Tianhe Graphite Co. Ltd. for supporting appropriate pore former graphite.
文摘A porous NiO/yttria-stabilized zirconia was prepared by gel casting technique. anode substrate for tubular solid oxide fuel cells Nano-scale samaria-doped ceria (SDC) particles were formed onto the anode substrate to modify the anode microstructure by the impregnation of solution of Sm(NO3)3 and Ce(NO3)3. Electrochemical impedance spectroscopy, current-voltage and current-powder curves of the cells were measured using an electrochemical workstation. Scanning electron microcopy was used to observe the microstructure. The results indicate that the stability of the performance of the cell operated on humidified methane can be significantly improved by incorporating the nano-structured SDC particles, compared with the unmodified cell. This verifies that the coated SDC electrodes are very effective in suppressing catalytic carbon formation by blocking methane from approaching the Ni, which is catalytically active towards methane pyrolysis. In addition, it was found that a small amount of deposited carbon is beneficial to the performance of the anode. The cell showed a peak power density of 225 mW/cm^2 when it was fed with H2 fuel at 700 ℃, but the power density increased to 400 mW/cm^2 when the fuel was switched from hydrogen to methane at the same flow rate. Methane conversion achieved about 90%, measured by gas chromatogram with a 10.0 mL/min flow rate of fuel at 700 ℃. Although the carbon deposition was not suppressed absolutely, some deposited carbon was beneficial for performance improvement.
基金National Natural Science Foundation of China(20590360)New Century Excellent Talent Project of China(NCET-05-0783)
文摘Silica-supported CuCo catalysts were prepared by impregnation method with different impregnation sequence for higher alcohols synthesis. These catalysts were characterized by H2-TPR, XRD, N2 adsorption, XPS techniques and CO selective hydrogenation reaction measurement. The effects of impregnation sequence on the structure and performance of catalysts were investigated, and there were important influences on the selectivity to higher alcohols. There was a strong synergistic effect between copper and cobalt for the co-impregnated sample. The CuCo/SiO2 catalyst prepared by co- impregnation showed a better yield of total alcohols, and a higher selectivity to total alcohols which reached 51.5%.
基金supported by the financial support of National Basic Research Program of China (2012CB723105)National Natural Science Foundation of China (20976117)+1 种基金Shanxi Province Natural Science Foundation(2010011014-3)Shanxi Province Basic Conditions Platform for Science and Technology Project (2010091015)
文摘High-pressure impregnation, a new preparation method for sorbents to remove H2S from hot coal gas, is introduced in this paper. Semi-coke (SC) and ZnO is selected as the support and active component of sorbent, respectively. The sorbent preparation process includes high-pressure impregnation, filtration, ovendry and calcination. The aim of this research is to primarily study the effects of the impregnation pressure on physical properties and desulfurization ability of the sorbent. The desulfurization experiment was carried out in a fixed-bed reactor at 500 ~C and a simulated coal gas used in this work was composed of CO (33 vol%), H2 (39 vol%), H2S (300 ppm in volume), and N2 (balance). Experimental results show that the pore structure of the SC support can be improved effectively and ZnO active component can be uniformly dispersed on the support, with the small particle size of 10-500 nm. Sorbents prepared using high-pressure impregnation have better desulfurization capacity and their active components have higher utilization rate. P20-ZnSC sorbent, obtained by high-pressure impregnation at 20 atm, has the best desulfurization ability with a sulfur capacity of 7.54 g S/100g sorbent and a breakthrough time of 44 h. Its desulfurization precision and efficiency of removing H2S from the middle temperature gases can reach 〈 1 ppm and 〉99.7%, respectively, before sorbent breakthrough.
基金supported by the National Basic Research Program of China(2012CB723105)the National Natural Science Foundation of China(20976117)the Technological Innovation Programs of Higher Education Institutions in Shanxi(2013JYT113)
文摘Zn-Mn-Cu/SC(U) sorbent was hydrothermally synthesized by ultrasound-assisted high-pressure impregnation method with semi-coke(SC)as support and the mixed solution of zinc nitrate,manganese nitrate and copper nitrate as active component precursors.The desulfurization performances of hot coal gas on the prepared sorbent at a mid-temperature of 500°C were tested in fixed-bed reactor.Morphology and pore structure of the prepared sorbent were also characterized by TEM,N2adsorption/desorption isotherms and XRD.For comparison,the sorbent of Zn-Mn-Cu/SC prepared by conventional high-pressure impregnation was also evaluated and characterized in order to study the effects of ultrasound treatment.Zn-Mn-Cu/SC(U) sorbent prepared by high-pressure impregnation under ultrasound-assisted condition showed a better desulfurization performance than Zn-Mn-Cu/SC.It could remove H2 S from 1000×10-6m3/m3 to 0.1×10-6m3/m3 at 500°C and maintained for 12.5 h with the sulfur capacity of 7.74%,in which both the breakthrough time and sulfur capacity were about 32% and 51% higher than those of Zn-Mn-Cu/SC sorbent.The introduction of ultrasound during high-pressure impregnation process greatly improved the morphology and pore structure of the sorbent.The ultrasonic treatment made particle size of active components smaller and made them more evenly disperse on semi-coke support,which provided more opportunities to contact with H2S in coal-based gases.However,there were no any difference in compositions and existing forms of active components on the Zn-Mn-Cu/SC and Zn-Mn-Cu/SC(U) sorbents.
文摘Solid oxide fuel cell(SOFC) electrodes,after a high temperature sintering,may be impregnated to deposit nanoparticles within their pores to enhance the catalytic function.Samarium doped CeO2(SDC) nanoparticles were infiltrated into(Pr0.7Ca0.3)0.9MnO3-δ(PCM) cathode of anode supported SOFC cells.The cell with 2.6 mg/cm2 SDC impregnated in cathode showed the maximum power density of 580 mW/cm2 compared with 310 mW/cm2 of the cell without impregnation at 850 °C.The cells were also characterized with the impeda...
文摘The surface of as-prepared LiMn2O4 was modified with ZnO, Al2O3, CoO and LiCoO2 using a simple nitrate melting impregnation method. Transmission electron microscopy (TEM) studies indicated that oxide nano- particles in the range of 10~50 nm are coated on the surface of the spinel. The surface modified samples show better capacity retention than the unmodified LiMn2O4 spinel at both room temperature and 55℃. Among these samples, the ZnO-modified LiMn2O4 shows the best combination of a high capacity and a low capacity fading rate of 0.036% per cycle at room temperature and 0.064% per cycle at 55℃. The improvement for surface modified LiMn2O4 can be attributed to the inhibition of Mn dissolution and O losses on the surface.
基金supported by the National Key R&D Program of China(2016YFA0202900)the National Natural Science Foundation of China(21622606)+1 种基金Zhejiang Provincial Natural Science Foundation of China(LR18B060001)the Fundamental Research Funds for the Central Universities~~
文摘Supported metal catalysts play a vital role in the chemical industry, and the metal-support interaction is an important property of the catalyst. However, in the traditional impregnation method, it is difficult to obtain sufficient metal-support interactions owing to the mobility of the metal precursor during evaporation drying. Here, freeze drying is applied during impregnation instead of evaporation drying for enhancing the metal-support interactions. 57 Fe ZSM-5 was chosen as a representative catalyst. A quantitative analysis was conducted based on Mossbauer spectroscopy. Compared with traditional evaporation-drying catalyst, freeze-drying catalyst has stronger metal-support interactions. In addition, more iron species are confined in the channel and smaller metal sizes and less diversity are obtained. The compositional change is also proved because of the superior performance of the freeze-drying catalyst during N2O decomposition. This method can be extended to other supported metal catalysts prepared through an impregnation method, which can be used to tune the metal-support interactions and metal sizes.
文摘Felt base carbon/carbon composites fabricated by super-high pressure impregnation carbonization process (SPIC) were heat treated at high temperature 2773K. The oxidation properties of felt base carbon/carbon composites were investigated at different temperatures (773-1173K), and the microstructures of carbon/carbon composites were studied by SEM and X-ray diffraction. The experimental results showed that the inter-laminar distance of (002) plane (d002) deceased while the microcrystalline stack height (Lc) increased. The oxidation rate of felt base carbon/carbon composites was invari-able at certain temperatures. The oxidation mechanism of carbon/carbon composites changed remarkably at the oxidation temperature 973K. At the initial oxidation stage of carbon/carbon composites, carbon matrix was oxidized much more rapidly than carbon felt.
基金Projects (21207093,51004072) supported by the National Natural Science Foundation of China for YouthProject (LJQ2014023) supported by the Liaoning Excellent Talents in University,China+1 种基金Project (L20150178) supported by the General Scientific Research Projects Foundation of Liaoning Educational Committee,ChinaProject (N140303002) supported by the Fundamental Research Funds for the Central Universities,China
文摘To enhance the photocatalytic activity of B-BiVO4,Ni-doped B?BiVO4photocatalyst(Ni-B-BiVO4)was synthesized through sol-gel and impregnation method.The photocatalysts were characterized by XPS,XRD,SEM,EDS,BET and UV-Vis DRS techniques.The results showed that single or double doping did not change the crystalline structure and morphology,but the particle size decreased with Ni doping.The band gap energy absorption edge of Ni-B-BiVO4shifted to a longer wavelength compared with undoped,B or Ni single doped BiVO4.More V4+and surface hydroxyl oxygen were observed in BiVO4after Ni-B co-doping.When the optimal mass fraction of Ni is0.30%,the degradation rate of MO in50min is95%for0.3Ni-B-BiVO4sample which also can effectively degrade methyl blue(MB),acid orange(AOII)II and rhodamine B(RhB).The enhanced photocatalytic activity is attributed to the synergistic effects of B and Ni doping.
文摘Two types of small iron clusters supported on γ-Al2O3-RT(dehydroxylated at room temperature) and γ-Al2O3-800 (dehydroxylated at 800 ℃) were prepared by solvated metal atom impregnation (SMAI) techniques. The iron atom precursor complex, bis(toluene)iron(0) formed in the metal atom reactor, was impregnated into γ-Al2O3 having different concentrations of surface hydroxyl groups to study the effect of surface hydroxylation on the crucial stage of iron cluster formation. Catalysts prepared in this way were characterized by TEM, Mǒssbauer, and chemisorption measurements, and the results show that higher concentration of surface hydroxyl groups of γ-Al2O3-RT favors the formation of more positively charged supported iron cluster Fen/γ-Al2O3-RT, and the lower concentration of surface hydroxyl groups of γ-Al2O3-800 favors the formation of basically neutral supported iron cluster Fen/γ-Al2O3-800. The measured results also indicate that the higher concentration of surface hydroxyl groups causes the rapid decomposition of precursor complex, bis(toluene)iron(0), and favors the formation of relatively large iron cluster. Consequently, these two types of catalysts show different catalytic properties in Fischer-Tropsch reaction. The catalytic pattern of Fen/γ-Al2O3-RT in F-T reaction is similar to that of the unreduced γ-Fe2O3 and that of Fen/γ-Al2O3-800 is similar to that of the reduced α-Fe2O3.
基金the financial support of Shanghai Research Institute of Petrochemical Technology,SINOPEC
文摘Two silica-supported cobalt catalysts were prepared by incipient wetness impregnation under atmospheric and vacuum conditions.N2 ph- ysisorption,H2 chemisorption,XRD,SEM,TEM,XPS and H2-TPR were used to characterize the catalysts.The results showed that the impregnation methods had an effect on the size,dispersion and reducibility of cobalt particles.Under vacuum conditions,cobalt-containing steeping liquor could penetrate into the inner pores of silica support and more bivalent cobalt oxides were formed in the Co3O4 crystallites.Furthermore,cobalt precursors were rarely inclined to agglomerate and the smaller cobalt particles were uniform on the support,which led to the higher activity of the Co/SiO2(B)catalyst than the normal one under the reaction conditions of 483- 523 K,1 - 2 MPa,gas hourly space velocity of 500–1000 h-1 and molar ratio of H2/CO=0.5 - 2.0.
文摘An efficient technology of impregnation of carbonate crushed stone by oil-product based on SCF-impregnation process usage with propane/butane solvent was developed. Regular impregnation throughout the volume of crushed stone sample is achieved. As a result of the appliance of proposed technology, the humidity of the treated crushed stone samples decreased down to 0.54%.
文摘In order to improve the properties of purging plugs and to prolong their service life,this work attempted to impregnate alumina-spinel castables for purging plugs in refining ladle with saturated magnesium chloride solution under vacuum.After being impregnated for the first time,the specimens were treated in two different ways:(1)dried at 110℃for 24 h;(2)heated at 600℃for 3 h.Then they were impregnated for the second time.All specimens were heated at 1550℃for 3 h,then the cold properties and the high temperature properties were tested according to corresponding standards.Test results were compared and analyzed.The results show that:after being impregnated,the specimen have both better cold properties and high temperature properties,the microstructure analysis result proves that it is attributed to in situ formed spinel.However,because MgO produced by MgCl2-6H20 decomposing above 527℃can hydrate and destroy specimen microstructure,which can make the properties of specimens impregnated in the second way get worse.By comprehensive consideration,the first scheme way is more suitable.
文摘A novel greener method to impregnate silver nanoparticles (AgNPs) into microcrystalline cellulose (MCC) by curry leaf (Murraya koenigii) extract mediated biological process is presented. The active reduction of silver ions by curry leaf extract was explored for the in situ impregnation AgNPs into MCC. Transmission electron microscopy (TEM) analyses of MCC coated with AgNPs showed the formation of silver particle sizes in the range of 10-25 nm and have a spherical shape. Further the, EDS analysis of MCC/Ag nanocomposite confirms the formation of Ag structure on microcrystalline cellulose. Solvent casting of poly(lactic-acid) was used to produce composite films containing silver impregnated MCC aiming for antimicrobial applications.
文摘In this paper, we deals with mechanical performance of resin impregnation with natural fiber and fiber reinforced composites. The effect of the addition of a rein impregnation process on static strength of the injection molded composites was investigated by carrying out tensile and banding tests, followed by Scanning electron microscopy (SEM) observation of fiber surface and fracture surface of composites. The tensile strength of natural fiber and natural fiber reinforced composites with resin impregnation method increases with Polyvinyl alcohol (PVA) impregnation. In addition, Phenol resin impregnation recovers fiber tensile strength after alkali treatment. Resin impregnation causes decrease in contact surface area;however, it does not cause decrease in mechanical properties. Our results suggest that the using rein impregnation method has better effect on the mechanical properties of natural fiber reinforced Polypropylene (PP) composites.