Alzheimer’s disease is initially thought to be caused by age-associated accumulation of plaques,in recent years,research has increasingly associated Alzheimer’s disease with lysosomal storage and metabolic disorders...Alzheimer’s disease is initially thought to be caused by age-associated accumulation of plaques,in recent years,research has increasingly associated Alzheimer’s disease with lysosomal storage and metabolic disorders,and the explanation of its pathogenesis has shifted from amyloid and tau accumulation to oxidative stress and impaired lipid and glucose metabolism aggravated by hypoxic conditions.However,the underlying mechanisms linking those cellular processes and conditions to disease progression have yet to be defined.Here,we applied a disease similarity approach to identify unknown molecular targets of Alzheimer’s disease by using transcriptomic data from congenital diseases known to increase Alzheimer’s disease risk,namely Down syndrome,Niemann-Pick type C disease,and mucopolysaccharidoses I.We uncovered common pathways,hub genes,and miRNAs across in vitro and in vivo models of these diseases as potential molecular targets for neuroprotection and amelioration of Alzheimer’s disease pathology,many of which have never been associated with Alzheimer’s disease.We then investigated common molecular alterations in brain samples from a Niemann-Pick type C disease mouse model by juxtaposing them with brain samples of both human and mouse models of Alzheimer’s disease.Detailed phenotypic,molecular,chronological,and biological aging analyses revealed that the Npc1tm(I1061T)Dso mouse model can serve as a potential short-lived in vivo model for brain aging and Alzheimer’s disease research.This research represents the first comprehensive approach to congenital disease association with neurodegeneration and a new perspective on Alzheimer’s disease research while highlighting shortcomings and lack of correlation in diverse in vitro models.Considering the lack of an Alzheimer’s disease mouse model that recapitulates the physiological hallmarks of brain aging,the short-lived Npc1^(tm(I1061T)Dso) mouse model can further accelerate the research in these fields and offer a unique model for understanding the molecular mechanisms of Alzheimer’s disease from a perspective of accelerated brain aging.展开更多
Copper-based catalysts exhibit excellent three-way catalytic activity but tend to undergo agglomeration at high temperatures,resulting in inadequate thermal stability.This study focuses on construction of strong metal...Copper-based catalysts exhibit excellent three-way catalytic activity but tend to undergo agglomeration at high temperatures,resulting in inadequate thermal stability.This study focuses on construction of strong metal-support interactions through La doping to improve the thermal stability and resistance to thermal aging of the catalysts.Cu/CeZrLaO_(2)demonstrates superior thermal aging resistance even after thermal aged at 1000℃for 3 h,which still maintains 88%and 100%for CO and HC conversion,and more than 65%NO conversion at the simulated vehicle exhaust atmosphere.The introduction of La into the CeZrO_(2)support forms Ce-Zr-La-O ternary solid solution,enhancing the structural stability and suppressing grain growth at elevated temperatures.Meanwhile,the doping of this trivalent generates a large number of oxygen vacancies in the catalyst,which improves the dispersion of copper through the anchoring effect.Crucially,La substantially strengthens the metal-support interaction,preventing sintering and agglomeration of copper under harsh conditions,ultimately maintaining the dispersion of copper on the catalyst surface.The present work effectively improves the thermal stability of the Cu/CeZrO_(2)catalyst,establishing a foundation for the further industrial application of the copper-based three-way catalyst.展开更多
Catalytic aryl ether C—O bonds hydrogenolysis was an important route to convert lignite into high valueadded chemicals.Solid super acid 10%Ni-S_(2)O_(8)^(2-)=ZrO_(2) catalysts were successfully synthesized and evalua...Catalytic aryl ether C—O bonds hydrogenolysis was an important route to convert lignite into high valueadded chemicals.Solid super acid 10%Ni-S_(2)O_(8)^(2-)=ZrO_(2) catalysts were successfully synthesized and evaluated their performance in catalytic hydrolysis of lignite derivatives.The excellent performance of 10%Ni-S_(2)O_(8)^(2-)=ZrO_(2) stems from the synergistic interaction between metallic and acidic sites.Specifically,the acidic sites generated by S_(2)O_(8)^(2-) facilitate the adsorption of O atoms in the substrate,whereas the metal sites optimize the process of hydrogen adsorption and activation and promote the generation of hydrogen radicals,which further enhances the ability to break C—O bonds.Thus,10%Ni-S_(2)O_(8)^(2-)=ZrO_(2) exhibits more significantcatalytic activity compared to 10%Ni-ZrO_(2) prepared from pure ZrO_(2) as a support.Characterization results showed that the 10%Ni-S_(2)O_(8)^(2-)=ZrO_(2) catalyst prepared by sodium borohydride reduction method presented a uniform pore structure,which effectively promoted the dispersion of metal Ni on the catalyst surface.Complete conversion of diphenyl ether(DPE)can be achieved under relatively mild conditions,and excellent hydrogenolysis activity is also demonstrated for other lignite derivatives containing C—O bonds.The possible reaction mechanism of DPE hydrogenolysis in the H_(2)-isopropanol system was investigated.This work represents a significantstep forward in the design of highly efficientsolid super acid catalysts.展开更多
In order to improve the photocatalytic performance of mesoporous titania under visible light, a series of photocatalysts of S and Ag co-doped mesoporous titania have been successfully prepared by template method using...In order to improve the photocatalytic performance of mesoporous titania under visible light, a series of photocatalysts of S and Ag co-doped mesoporous titania have been successfully prepared by template method using thiourea, AgNO3 and tetrabutyl titanate as precursors and Pluronic P123 （EO20PO70EO20） as template. Scanning electron microscopy （SEM）, X-ray diffraction （XRD）, nitrogen adsorption-desorption measurements, and UV-visible spectroscopy （UV-Vis） were employed to characterize the morphology, crystal structure, surface structure, and optical absorption properties of the samples. The microcrystal of the photocatalysts consisted of anatase phase and was approximately present in the form of spherical particle. The photocatalytic performance was studied by photodegradation methyl orange （MO） in water under UV and visible light irradiation. The calcination temperature and the doping content influenced the photoactivity. In addition, the possibility of cyclic usage of co-doped mesoporous titania was also confirmed, the photocatalytic activity of mesoporous titania remained above 89% of that of the fresh sample after being used four times. It was shown that the co-doped mesoporous titania could be activated by visible light and could thus be potentially applied for the treatment of water contaminated by organic pollutants. The synergistic effect of sulfur and silver co-doping played an important role in improving the photocatalytic activity.展开更多
A series of perovskite type oxides and supported Ag catalysts were prepared, and characterized by X ray diffraction (XRD) and X ray photoelectron spectroscopy (XPS). The catalytic activities of the catalyst...A series of perovskite type oxides and supported Ag catalysts were prepared, and characterized by X ray diffraction (XRD) and X ray photoelectron spectroscopy (XPS). The catalytic activities of the catalysts as well as influencing factors on catalytic activity have been investigated for the simultaneous removal of NOx and diesel soot particulate. An increase in catalytic activity for the selective reduction of NOx was observed with Ag addition in these perovskite oxides, especially with 5% Ag loading. This catalyst could be a promising candidate of catalytic material for the simultaneous elimination of NOx and diesel soot.展开更多
In this protocol, Ag supported on the hydroxyapatite-core–shell magnetic γ-Fe2O3nanoparticles（γFe2O3@HAp-Ag NPs） as a novel, efficient, and magnetically recyclable catalyst is synthesized, and characterized by tr...In this protocol, Ag supported on the hydroxyapatite-core–shell magnetic γ-Fe2O3nanoparticles（γFe2O3@HAp-Ag NPs） as a novel, efficient, and magnetically recyclable catalyst is synthesized, and characterized by transmission electron microscopy（TEM）, scanning electron microscopy（SEM）, Fourier transform infrared spectroscopy（FT-IR）, X-ray diffraction（XRD）, and vibrating sample magnetometry（VSM）. The use of the catalyst is described in the synthesis of coumarin derivatives by the Pechmann condensation of various phenols with β-ketoesters under solvent- and halogen-free conditions at 80℃.This novel and inexpensive method offers advantages, such as recyclability simple experimental protocol, short reaction time, minimal work-up procedure, and excellent yields of products, together with desirable, eco-friendly, green aspects by avoiding toxic elements and solvents, and ease of recovery from the reaction mixture using an external magnet.展开更多
Isotactic poly（butene-1） （iPB） with spherical morphology was synthesized successfully with bulk precipitation polymerization without post-treatment of the products. The bulk precipitation polymerization process ma...Isotactic poly（butene-1） （iPB） with spherical morphology was synthesized successfully with bulk precipitation polymerization without post-treatment of the products. The bulk precipitation polymerization process made it possible for iPB to be used as general plastic due to the acceptable decreased cost compared with the solution polymerization process. The influence of catalyst residues on the aging and thermal stability of iPB synthesized by bulk precipitation polymerization method was investigated by gel permeation chromatography, mechanical performance testing, thermogravimetric analysis and infrared spectroscopic analysis. Commercial iPB and the lab-made iPB with varied catalyst residue contents were studied. The results demonstrated that the catalyst residues played an important role in the aging process of the iPB. A possible mechanism of aging promotion by catalyst residues was proposed.展开更多
A novel plasmonic photo‐Fenton catalyst of Ag/AgCl/Fe‐S was synthesized by ion exchange and photoreduction methods.The obtained catalyst was characterized by X‐ray diffraction,X‐ray photoelectron spectroscopy,scan...A novel plasmonic photo‐Fenton catalyst of Ag/AgCl/Fe‐S was synthesized by ion exchange and photoreduction methods.The obtained catalyst was characterized by X‐ray diffraction,X‐ray photoelectron spectroscopy,scanning electron microscope imaging,and Brunauer‐Emmett‐Teller measurements.Moreover,the photocatalytic activity of Ag/AgCl/Fe‐S was investigated for its degradation activity towards bisphenol A(BPA)as target pollutant under visible light irradiation.The effects of H2O2concentration,pH value,illumination intensity,and catalyst dosage on BPA degradation were examined.Our results indicated that the Ag/AgCl material was successfully loaded onto Fe‐sepiolite and showed a high photocatalytic activity under illumination by visible light.Furthermore,active species capture experiments were performed to explore the photocatalytic mechanism of the Ag/AgCl/Fe‐S in this heterogeneous photo‐Fenton process,where the major active species included hydroxyl radicals(?OH)and holes(h+).展开更多
Ag‐Cu‐Cl/BaCO3 catalysts with different Cl and Cu loadings, prepared by the reduction deposition impregnation method, were investigated for gas‐phase epoxidation of propylene by molecular oxygen and characterized b...Ag‐Cu‐Cl/BaCO3 catalysts with different Cl and Cu loadings, prepared by the reduction deposition impregnation method, were investigated for gas‐phase epoxidation of propylene by molecular oxygen and characterized by X‐ray diffraction, X‐ray photoelectron spectroscopy and O2 temperatureprogrammed desorption. Ag‐Cu‐Cl/BaCO3 catalyst with 0.036 wt% Cu and 0.060 wt% Cl exhibitedthe highest catalytic performance for gas‐phase epoxidation of propylene by molecular oxygen. Apropylene oxide selectivity of 83.7% and propylene conversion of 1.2% were achieved under thereaction conditions of 20% C3H6‐10% O2‐70% N2, 200 °C, 0.1 MPa and 3000 h?1. Increasing the Clloading allowed Ag to ensemble easier, whereas changing the Cu loading showed little effect on Agcrystallite size. The appropriate Cl loading of Ag‐Cu‐Cl/BaCO3 catalyst can reduce the dissociationadsorption of oxygen to atomic oxygen species leading to the combustion of propylene to CO2, whichbenefits epoxidation of propylene by molecular oxygen. Excessive Cl loading of Ag‐Cu‐Cl/BaCO3catalyst decreases propylene conversion and propylene oxide selectivity remarkably because of Clpoisoning. The appropriate Cu loading of Ag‐Cu‐Cl/BaCO3 catalyst is efficient for the epoxidation ofpropylene by molecular oxygen, and an excess Cu loading decreases propylene oxide selectivitybecause the aggregation of Cu species increases the exposed surfaces of Ag nanoparticles, whichwas shown by slight increases in atomic oxygen species adsorbed. The appropriate loadings of Cu and Cl of Ag‐Cu‐Cl/BaCO3 catalyst are important to strike the balance between molecular oxygen and atomic oxygen species to create a favorable epoxidation of propylene by molecular oxygen.展开更多
The performance of lignin depolymerization is basically determined by the interunit C–O and C–C bonds.Numerous C–O bond cleavage strategies have been developed, while the cleavage of C–C bond between the primary a...The performance of lignin depolymerization is basically determined by the interunit C–O and C–C bonds.Numerous C–O bond cleavage strategies have been developed, while the cleavage of C–C bond between the primary aromatic units remains a challenging task due to the high dissociation energy of C–C bond.Herein, a multifunctional Ru Re alloy catalyst was designed, which exhibited exceptional catalytic activity for the cleavage of both C–O and C–C linkages in a broad range of lignin model compounds(β-1, a-5, 5–5,β-O-4, 4-O-5) and two stubborn lignins(kraft lignin and alkaline lignin), affording 97.5% overall yield of monocyclic compounds from model compounds and up to 129% of the maximum theoretical yield of monocyclic products based on C–O bonds cleavage from realistic lignin. Scanning transmission electron microscopy(STEM) characterization showed that Ru Re(1:1) alloy particles with hexagonal close-packed structure were homogeneously dispersed on the support. Quasi-in situ X-ray photoelectron spectroscopy(XPS), and X-ray absorption spectroscopy(XAS) indicate that Ru species were predominantly metallic state, whereas Re species were partially oxidized;meanwhile, there was a strong interaction between Ru and Re, where the electron transfer from Re to Ru was occurred, resulting in great improvement on the capability of C–O and C–C bonds cleavage in lignin conversion.展开更多
The metal oxide promoter decisively influences the overall performance of Fe catalysts in the direct hydrogenation of CO_(2)to C_(5+)hydrocarbons.However,the roles of metal oxide promoter for Fe catalysts,particularly...The metal oxide promoter decisively influences the overall performance of Fe catalysts in the direct hydrogenation of CO_(2)to C_(5+)hydrocarbons.However,the roles of metal oxide promoter for Fe catalysts,particularly ZrO_(2),have rarely been investigated.To plug this knowledge gap,a new Fe catalyst promoted with Na and partially reduced ZrO_(x)(Na-FeZrO_(x-9))was developed in this study;the catalyst helped produce C_(5+)hydrocarbons in remarkably high yield(26.3%at 360℃).In contrast to ZrO_(x)-free Fe-oxide,NaFeZrO_(x)-9 exhibited long-term stability for CO_(2)hydrogenation(750 h on-stream).The findings revealed multiple roles of ZrO_(x).Notably,ZrO_(x)decorated the Fe-oxide particles after calcination,thereby suppressing excess particle aggregation during the reaction,and acted as a"coke remover"to eliminate the carbon deposited on the catalyst surface.Additionally,oxygen vacancy(O_(v))sites in ZrO_(x)and electron transfer from ZrO_(x)to Fe sites facilitated the adsorption of CO_(2)at the Zr-Fe interface.展开更多
In this study,Ag/γ-Al_(2)O_(3)catalysts were synthesized by an Ar dielectric barrier discharge plasma using silver nitrate as the Ag source andγ-alumina(γ-Al_(2)O_(3))as the support.It is revealed that plasma can r...In this study,Ag/γ-Al_(2)O_(3)catalysts were synthesized by an Ar dielectric barrier discharge plasma using silver nitrate as the Ag source andγ-alumina(γ-Al_(2)O_(3))as the support.It is revealed that plasma can reduce silver ions to generate crystalline silver nanoparticles(Ag NPs)of good dispersion and uniformity on the alumina surface,leading to the formation of Ag/γ-Al_(2)O_(3)catalysts in a green manner without traditional chemical reductants.Ag/γ-Al_(2)O_(3)exhibited good catalytic activity and stability in CO oxidation reactions,and the activity increased with increase in the Ag content.For catalysts with more than 2 wt%Ag,100%CO conversion can be achieved at 300°C.The catalytic activity of the Ag/γ-Al_(2)O_(3)catalysts is also closely related to the size of theγ-alumina,where Ag/nano-γ-Al_(2)O_(3)catalysts demonstrate better performance than Ag/micro-γ-Al_(2)O_(3)catalysts with the same Ag content.In addition,the catalytic properties of plasma-generated Ag/nano-γ-Al_(2)O_(3)(Ag/γ-Al_(2)O_(3)-P)catalysts were compared with those of Ag/nano-γ-Al_(2)O_(3)catalysts prepared by the traditional calcination approach(Ag/γ-Al_(2)O_(3)-C),with the plasma-generated samples demonstrating better overall performance.This simple,rapid and green plasma process is considered to be applicable for the synthesis of diverse noble metal-based catalysts.展开更多
Methyl glycolate is a good solvent and can be used as feedstock for the synthesis of some important organic chemicals. Catalytic hydrogenation of dimethyl oxalate （DMO） over copper-silver catalyst supported on silic...Methyl glycolate is a good solvent and can be used as feedstock for the synthesis of some important organic chemicals. Catalytic hydrogenation of dimethyl oxalate （DMO） over copper-silver catalyst supported on silica was studied. The Cu-Ag/SiO2 catalyst supported on silica sol was prepared by homogeneous deposition-precipitation of the mixture of aqueous euprammonia complex and silica sol. The proper active temperature of Cu-Ag/SiO2 catalyst for hydrogenation of DMO was 523-623 K. The most preferable reaction conditions for methyl glycolate （MG） were optimized： temperature at 468-478 K, 40-60 mesh catalyst diameter, H2/DMO ratio 40, and 1.0 h^-1 of LHSV.展开更多
To reveal how cerium stabilizes Cu/SAPO-34 at low-temperature hydrothermal aging,various amounts of cerium were introduced into Cu/SAPO-34 via impregnation method and treated at 70℃with RH 80%for 96 h.Cerium as Ce^(3...To reveal how cerium stabilizes Cu/SAPO-34 at low-temperature hydrothermal aging,various amounts of cerium were introduced into Cu/SAPO-34 via impregnation method and treated at 70℃with RH 80%for 96 h.Cerium as Ce^(3+)and CeO_(2)nanoparticle is located on the surface of Cu/SAPO-34,and Ce^(3+)plays a vital role on gradually decreasing surface acidity and blocking defect sites with an increase of Ce loading.After hydrothermal aging,Cu/SAPO-34 with high Ce loading shows the superior SCR activity comparable to fresh samples.It is proven that the surface acidity determines the stability of the structure during hydrothermal aging process,and lower surface acidity prevents the number of Cu(Ⅱ)ions from decreasing significantly.Furthermore,the structure's stability helps the recovery of Cu(Ⅱ)ions and renders an outstanding regene ration ability.Our finding paves the way for the design of new Cu/SAPO-34catalysts with good SCR activity and long-term stability in real application.展开更多
The catalytic decomposition of NO over Ag-ZSM-5 catalyst prepared by ion-exchange was investigated. The exchanged silver in the zeolite was reduced and it collected in the course of the reaction to form silver particl...The catalytic decomposition of NO over Ag-ZSM-5 catalyst prepared by ion-exchange was investigated. The exchanged silver in the zeolite was reduced and it collected in the course of the reaction to form silver particles of about 20 nm. The catalytic reaction induced a pronounced restructuring of the Ag particles through preferential formation of the (111) facets. These facets were shown to hind a tightly bound oxygen species (O-gamma). The O-gamma species occupies the active sites for NO adsorption resulting in catalyst deactivation. It could be removed by appropriate reducing agents, such as CO, to recover the active sites at elevated temperatures.展开更多
Tuning metal-support interactions(MSIs)is an important strategy in heterogeneous catalysis to realize the desirable metal dispersion and redox ability of metal catalysts.Herein,we use pre-reduced Co_(3)O_(4)nanowires(...Tuning metal-support interactions(MSIs)is an important strategy in heterogeneous catalysis to realize the desirable metal dispersion and redox ability of metal catalysts.Herein,we use pre-reduced Co_(3)O_(4)nanowires(Co-NWs)in situ grown on monolithic Ni foam substrates to support Ag catalysts(Ag/Co-NW-R)for soot combustion.The macroporous structure of Ni foam with crossed Co_(3)O_(4)nanowires remarkably increases the soot-catalyst contact effi ciency.Our characterization results demonstrate that Ag species exist as Ag 0 because of the equation Ag^(+)+Co^(2+)=Ag^(0)+Co^(3+),and the pre-reduction treatment enhances interactions between Ag and Co_(3)O_(4).The number of active oxygen species on the Ag-loaded catalysts is approximately twice that on the supports,demonstrating the signifi cant role of Ag sites in generating active oxygen species.Additionally,the strengthened MSI on Ag/Co-NW-R further improves this number by increasing metal dispersion and the intrinsic activity determined by the turnover frequency of these oxygen species for soot oxidation compared with the catalyst without pre-reduction of Co-NW(Ag/Co-NW).In addition to high activity,Ag/Co-NW-R exhibits high catalytic stability and water resistance.The strategy used in this work might be applicable in related catalytic systems.展开更多
基金supported by the NIA/NIH(1K01AG060040).Studies performed by JN were funded by the NICHD/NIH(5R00HD096117)Microscopy Core Facility supported,in part,with funding from NIH-NCI Cancer Center Support Grant P30 CA016059.
文摘Alzheimer’s disease is initially thought to be caused by age-associated accumulation of plaques,in recent years,research has increasingly associated Alzheimer’s disease with lysosomal storage and metabolic disorders,and the explanation of its pathogenesis has shifted from amyloid and tau accumulation to oxidative stress and impaired lipid and glucose metabolism aggravated by hypoxic conditions.However,the underlying mechanisms linking those cellular processes and conditions to disease progression have yet to be defined.Here,we applied a disease similarity approach to identify unknown molecular targets of Alzheimer’s disease by using transcriptomic data from congenital diseases known to increase Alzheimer’s disease risk,namely Down syndrome,Niemann-Pick type C disease,and mucopolysaccharidoses I.We uncovered common pathways,hub genes,and miRNAs across in vitro and in vivo models of these diseases as potential molecular targets for neuroprotection and amelioration of Alzheimer’s disease pathology,many of which have never been associated with Alzheimer’s disease.We then investigated common molecular alterations in brain samples from a Niemann-Pick type C disease mouse model by juxtaposing them with brain samples of both human and mouse models of Alzheimer’s disease.Detailed phenotypic,molecular,chronological,and biological aging analyses revealed that the Npc1tm(I1061T)Dso mouse model can serve as a potential short-lived in vivo model for brain aging and Alzheimer’s disease research.This research represents the first comprehensive approach to congenital disease association with neurodegeneration and a new perspective on Alzheimer’s disease research while highlighting shortcomings and lack of correlation in diverse in vitro models.Considering the lack of an Alzheimer’s disease mouse model that recapitulates the physiological hallmarks of brain aging,the short-lived Npc1^(tm(I1061T)Dso) mouse model can further accelerate the research in these fields and offer a unique model for understanding the molecular mechanisms of Alzheimer’s disease from a perspective of accelerated brain aging.
基金Project supported by Taiyuan Ecological Environment Bureau(RH2400000291)the Natural Science Foundation of Shanxi(202203021211140,20210302124131)。
文摘Copper-based catalysts exhibit excellent three-way catalytic activity but tend to undergo agglomeration at high temperatures,resulting in inadequate thermal stability.This study focuses on construction of strong metal-support interactions through La doping to improve the thermal stability and resistance to thermal aging of the catalysts.Cu/CeZrLaO_(2)demonstrates superior thermal aging resistance even after thermal aged at 1000℃for 3 h,which still maintains 88%and 100%for CO and HC conversion,and more than 65%NO conversion at the simulated vehicle exhaust atmosphere.The introduction of La into the CeZrO_(2)support forms Ce-Zr-La-O ternary solid solution,enhancing the structural stability and suppressing grain growth at elevated temperatures.Meanwhile,the doping of this trivalent generates a large number of oxygen vacancies in the catalyst,which improves the dispersion of copper through the anchoring effect.Crucially,La substantially strengthens the metal-support interaction,preventing sintering and agglomeration of copper under harsh conditions,ultimately maintaining the dispersion of copper on the catalyst surface.The present work effectively improves the thermal stability of the Cu/CeZrO_(2)catalyst,establishing a foundation for the further industrial application of the copper-based three-way catalyst.
基金supported by the National Key Research and Development Program of China(2022YFB4101100)the National Natural Science Foundation of China(22178375 and 22478414)the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Catalytic aryl ether C—O bonds hydrogenolysis was an important route to convert lignite into high valueadded chemicals.Solid super acid 10%Ni-S_(2)O_(8)^(2-)=ZrO_(2) catalysts were successfully synthesized and evaluated their performance in catalytic hydrolysis of lignite derivatives.The excellent performance of 10%Ni-S_(2)O_(8)^(2-)=ZrO_(2) stems from the synergistic interaction between metallic and acidic sites.Specifically,the acidic sites generated by S_(2)O_(8)^(2-) facilitate the adsorption of O atoms in the substrate,whereas the metal sites optimize the process of hydrogen adsorption and activation and promote the generation of hydrogen radicals,which further enhances the ability to break C—O bonds.Thus,10%Ni-S_(2)O_(8)^(2-)=ZrO_(2) exhibits more significantcatalytic activity compared to 10%Ni-ZrO_(2) prepared from pure ZrO_(2) as a support.Characterization results showed that the 10%Ni-S_(2)O_(8)^(2-)=ZrO_(2) catalyst prepared by sodium borohydride reduction method presented a uniform pore structure,which effectively promoted the dispersion of metal Ni on the catalyst surface.Complete conversion of diphenyl ether(DPE)can be achieved under relatively mild conditions,and excellent hydrogenolysis activity is also demonstrated for other lignite derivatives containing C—O bonds.The possible reaction mechanism of DPE hydrogenolysis in the H_(2)-isopropanol system was investigated.This work represents a significantstep forward in the design of highly efficientsolid super acid catalysts.
基金This work was supported by the National Natural Sci- ence Foundation of China （No.41373127） and the Liaoning Provincial Natural Science Foundation of China （No.2013020121）.
文摘In order to improve the photocatalytic performance of mesoporous titania under visible light, a series of photocatalysts of S and Ag co-doped mesoporous titania have been successfully prepared by template method using thiourea, AgNO3 and tetrabutyl titanate as precursors and Pluronic P123 （EO20PO70EO20） as template. Scanning electron microscopy （SEM）, X-ray diffraction （XRD）, nitrogen adsorption-desorption measurements, and UV-visible spectroscopy （UV-Vis） were employed to characterize the morphology, crystal structure, surface structure, and optical absorption properties of the samples. The microcrystal of the photocatalysts consisted of anatase phase and was approximately present in the form of spherical particle. The photocatalytic performance was studied by photodegradation methyl orange （MO） in water under UV and visible light irradiation. The calcination temperature and the doping content influenced the photoactivity. In addition, the possibility of cyclic usage of co-doped mesoporous titania was also confirmed, the photocatalytic activity of mesoporous titania remained above 89% of that of the fresh sample after being used four times. It was shown that the co-doped mesoporous titania could be activated by visible light and could thus be potentially applied for the treatment of water contaminated by organic pollutants. The synergistic effect of sulfur and silver co-doping played an important role in improving the photocatalytic activity.
文摘A series of perovskite type oxides and supported Ag catalysts were prepared, and characterized by X ray diffraction (XRD) and X ray photoelectron spectroscopy (XPS). The catalytic activities of the catalysts as well as influencing factors on catalytic activity have been investigated for the simultaneous removal of NOx and diesel soot particulate. An increase in catalytic activity for the selective reduction of NOx was observed with Ag addition in these perovskite oxides, especially with 5% Ag loading. This catalyst could be a promising candidate of catalytic material for the simultaneous elimination of NOx and diesel soot.
文摘In this protocol, Ag supported on the hydroxyapatite-core–shell magnetic γ-Fe2O3nanoparticles（γFe2O3@HAp-Ag NPs） as a novel, efficient, and magnetically recyclable catalyst is synthesized, and characterized by transmission electron microscopy（TEM）, scanning electron microscopy（SEM）, Fourier transform infrared spectroscopy（FT-IR）, X-ray diffraction（XRD）, and vibrating sample magnetometry（VSM）. The use of the catalyst is described in the synthesis of coumarin derivatives by the Pechmann condensation of various phenols with β-ketoesters under solvent- and halogen-free conditions at 80℃.This novel and inexpensive method offers advantages, such as recyclability simple experimental protocol, short reaction time, minimal work-up procedure, and excellent yields of products, together with desirable, eco-friendly, green aspects by avoiding toxic elements and solvents, and ease of recovery from the reaction mixture using an external magnet.
基金financially supported by the National Key Technology R&D Program of China(No.2011BAE26B05)
文摘Isotactic poly（butene-1） （iPB） with spherical morphology was synthesized successfully with bulk precipitation polymerization without post-treatment of the products. The bulk precipitation polymerization process made it possible for iPB to be used as general plastic due to the acceptable decreased cost compared with the solution polymerization process. The influence of catalyst residues on the aging and thermal stability of iPB synthesized by bulk precipitation polymerization method was investigated by gel permeation chromatography, mechanical performance testing, thermogravimetric analysis and infrared spectroscopic analysis. Commercial iPB and the lab-made iPB with varied catalyst residue contents were studied. The results demonstrated that the catalyst residues played an important role in the aging process of the iPB. A possible mechanism of aging promotion by catalyst residues was proposed.
基金supported by the National Natural Science Foundation of China(41573118)Research Foundation of Education Bureau of Hunan Province,China(14B177)Special Project of Xiangtan University~~
文摘A novel plasmonic photo‐Fenton catalyst of Ag/AgCl/Fe‐S was synthesized by ion exchange and photoreduction methods.The obtained catalyst was characterized by X‐ray diffraction,X‐ray photoelectron spectroscopy,scanning electron microscope imaging,and Brunauer‐Emmett‐Teller measurements.Moreover,the photocatalytic activity of Ag/AgCl/Fe‐S was investigated for its degradation activity towards bisphenol A(BPA)as target pollutant under visible light irradiation.The effects of H2O2concentration,pH value,illumination intensity,and catalyst dosage on BPA degradation were examined.Our results indicated that the Ag/AgCl material was successfully loaded onto Fe‐sepiolite and showed a high photocatalytic activity under illumination by visible light.Furthermore,active species capture experiments were performed to explore the photocatalytic mechanism of the Ag/AgCl/Fe‐S in this heterogeneous photo‐Fenton process,where the major active species included hydroxyl radicals(?OH)and holes(h+).
基金supported by National Basic Research Program of China (2013CB933200)Commission of Science and Technology of Shanghai Municipality (15DZ1205305)~~
文摘Ag‐Cu‐Cl/BaCO3 catalysts with different Cl and Cu loadings, prepared by the reduction deposition impregnation method, were investigated for gas‐phase epoxidation of propylene by molecular oxygen and characterized by X‐ray diffraction, X‐ray photoelectron spectroscopy and O2 temperatureprogrammed desorption. Ag‐Cu‐Cl/BaCO3 catalyst with 0.036 wt% Cu and 0.060 wt% Cl exhibitedthe highest catalytic performance for gas‐phase epoxidation of propylene by molecular oxygen. Apropylene oxide selectivity of 83.7% and propylene conversion of 1.2% were achieved under thereaction conditions of 20% C3H6‐10% O2‐70% N2, 200 °C, 0.1 MPa and 3000 h?1. Increasing the Clloading allowed Ag to ensemble easier, whereas changing the Cu loading showed little effect on Agcrystallite size. The appropriate Cl loading of Ag‐Cu‐Cl/BaCO3 catalyst can reduce the dissociationadsorption of oxygen to atomic oxygen species leading to the combustion of propylene to CO2, whichbenefits epoxidation of propylene by molecular oxygen. Excessive Cl loading of Ag‐Cu‐Cl/BaCO3catalyst decreases propylene conversion and propylene oxide selectivity remarkably because of Clpoisoning. The appropriate Cu loading of Ag‐Cu‐Cl/BaCO3 catalyst is efficient for the epoxidation ofpropylene by molecular oxygen, and an excess Cu loading decreases propylene oxide selectivitybecause the aggregation of Cu species increases the exposed surfaces of Ag nanoparticles, whichwas shown by slight increases in atomic oxygen species adsorbed. The appropriate loadings of Cu and Cl of Ag‐Cu‐Cl/BaCO3 catalyst are important to strike the balance between molecular oxygen and atomic oxygen species to create a favorable epoxidation of propylene by molecular oxygen.
基金The National Natural Science Foundation of China(22078317,21878288,21721004,21690083)。
文摘The performance of lignin depolymerization is basically determined by the interunit C–O and C–C bonds.Numerous C–O bond cleavage strategies have been developed, while the cleavage of C–C bond between the primary aromatic units remains a challenging task due to the high dissociation energy of C–C bond.Herein, a multifunctional Ru Re alloy catalyst was designed, which exhibited exceptional catalytic activity for the cleavage of both C–O and C–C linkages in a broad range of lignin model compounds(β-1, a-5, 5–5,β-O-4, 4-O-5) and two stubborn lignins(kraft lignin and alkaline lignin), affording 97.5% overall yield of monocyclic compounds from model compounds and up to 129% of the maximum theoretical yield of monocyclic products based on C–O bonds cleavage from realistic lignin. Scanning transmission electron microscopy(STEM) characterization showed that Ru Re(1:1) alloy particles with hexagonal close-packed structure were homogeneously dispersed on the support. Quasi-in situ X-ray photoelectron spectroscopy(XPS), and X-ray absorption spectroscopy(XAS) indicate that Ru species were predominantly metallic state, whereas Re species were partially oxidized;meanwhile, there was a strong interaction between Ru and Re, where the electron transfer from Re to Ru was occurred, resulting in great improvement on the capability of C–O and C–C bonds cleavage in lignin conversion.
基金financial support from the National Research Council of Science&Technology(NST)grant funded by the Ministry of Science and ICT,Republic of Korea(CAP21012-100)the Korea Institute of Energy Technology Evaluation and Planning(KETEP),under the Ministry of Trade,Industry&Energy(MOTIE),Republic of Korea(20224C10300010)the KETEP grant funded by the MOTIE(20224000000440,Sector coupling energy industry advancement manpower training program)。
文摘The metal oxide promoter decisively influences the overall performance of Fe catalysts in the direct hydrogenation of CO_(2)to C_(5+)hydrocarbons.However,the roles of metal oxide promoter for Fe catalysts,particularly ZrO_(2),have rarely been investigated.To plug this knowledge gap,a new Fe catalyst promoted with Na and partially reduced ZrO_(x)(Na-FeZrO_(x-9))was developed in this study;the catalyst helped produce C_(5+)hydrocarbons in remarkably high yield(26.3%at 360℃).In contrast to ZrO_(x)-free Fe-oxide,NaFeZrO_(x)-9 exhibited long-term stability for CO_(2)hydrogenation(750 h on-stream).The findings revealed multiple roles of ZrO_(x).Notably,ZrO_(x)decorated the Fe-oxide particles after calcination,thereby suppressing excess particle aggregation during the reaction,and acted as a"coke remover"to eliminate the carbon deposited on the catalyst surface.Additionally,oxygen vacancy(O_(v))sites in ZrO_(x)and electron transfer from ZrO_(x)to Fe sites facilitated the adsorption of CO_(2)at the Zr-Fe interface.
基金financial support from National Natural Science Foundation of China(Nos.52004102 and 22078125)Postdoctoral Science Foundation of China(No.2021M690068)+2 种基金Fundamental Research Funds for the Central Universities(Nos.JUSRP221018 and JUSRP622038)Key Laboratory of Green Cleaning Technology and Detergent of Zhejiang Province(No.Q202204)Open Project of Key Laboratory of Green Chemical Engineering Process of Ministry of Education(No.GCP202112)。
文摘In this study,Ag/γ-Al_(2)O_(3)catalysts were synthesized by an Ar dielectric barrier discharge plasma using silver nitrate as the Ag source andγ-alumina(γ-Al_(2)O_(3))as the support.It is revealed that plasma can reduce silver ions to generate crystalline silver nanoparticles(Ag NPs)of good dispersion and uniformity on the alumina surface,leading to the formation of Ag/γ-Al_(2)O_(3)catalysts in a green manner without traditional chemical reductants.Ag/γ-Al_(2)O_(3)exhibited good catalytic activity and stability in CO oxidation reactions,and the activity increased with increase in the Ag content.For catalysts with more than 2 wt%Ag,100%CO conversion can be achieved at 300°C.The catalytic activity of the Ag/γ-Al_(2)O_(3)catalysts is also closely related to the size of theγ-alumina,where Ag/nano-γ-Al_(2)O_(3)catalysts demonstrate better performance than Ag/micro-γ-Al_(2)O_(3)catalysts with the same Ag content.In addition,the catalytic properties of plasma-generated Ag/nano-γ-Al_(2)O_(3)(Ag/γ-Al_(2)O_(3)-P)catalysts were compared with those of Ag/nano-γ-Al_(2)O_(3)catalysts prepared by the traditional calcination approach(Ag/γ-Al_(2)O_(3)-C),with the plasma-generated samples demonstrating better overall performance.This simple,rapid and green plasma process is considered to be applicable for the synthesis of diverse noble metal-based catalysts.
文摘Methyl glycolate is a good solvent and can be used as feedstock for the synthesis of some important organic chemicals. Catalytic hydrogenation of dimethyl oxalate （DMO） over copper-silver catalyst supported on silica was studied. The Cu-Ag/SiO2 catalyst supported on silica sol was prepared by homogeneous deposition-precipitation of the mixture of aqueous euprammonia complex and silica sol. The proper active temperature of Cu-Ag/SiO2 catalyst for hydrogenation of DMO was 523-623 K. The most preferable reaction conditions for methyl glycolate （MG） were optimized： temperature at 468-478 K, 40-60 mesh catalyst diameter, H2/DMO ratio 40, and 1.0 h^-1 of LHSV.
基金the National Natural Science Foundation of China for Youths(21908207)National Key R&D Program of China(2021YFB3503200)+3 种基金the Key R&D project of Shandong Province(2021CXGC010703)China Postdoctoral Science Foundation(2020M670659)Shanxi Province Science Foundation for Youths(201901D211224)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(2019L0575)。
文摘To reveal how cerium stabilizes Cu/SAPO-34 at low-temperature hydrothermal aging,various amounts of cerium were introduced into Cu/SAPO-34 via impregnation method and treated at 70℃with RH 80%for 96 h.Cerium as Ce^(3+)and CeO_(2)nanoparticle is located on the surface of Cu/SAPO-34,and Ce^(3+)plays a vital role on gradually decreasing surface acidity and blocking defect sites with an increase of Ce loading.After hydrothermal aging,Cu/SAPO-34 with high Ce loading shows the superior SCR activity comparable to fresh samples.It is proven that the surface acidity determines the stability of the structure during hydrothermal aging process,and lower surface acidity prevents the number of Cu(Ⅱ)ions from decreasing significantly.Furthermore,the structure's stability helps the recovery of Cu(Ⅱ)ions and renders an outstanding regene ration ability.Our finding paves the way for the design of new Cu/SAPO-34catalysts with good SCR activity and long-term stability in real application.
文摘The catalytic decomposition of NO over Ag-ZSM-5 catalyst prepared by ion-exchange was investigated. The exchanged silver in the zeolite was reduced and it collected in the course of the reaction to form silver particles of about 20 nm. The catalytic reaction induced a pronounced restructuring of the Ag particles through preferential formation of the (111) facets. These facets were shown to hind a tightly bound oxygen species (O-gamma). The O-gamma species occupies the active sites for NO adsorption resulting in catalyst deactivation. It could be removed by appropriate reducing agents, such as CO, to recover the active sites at elevated temperatures.
基金supported by the National Natu-ral Science Foundation of China(Nos.21878213,21808211)the open foundation of the State Key Laboratory of Chemical Engineer-ing(SKL-ChE-20B01)Authors are also grateful to the Program of Introducing Talents of Disciplines to China Universities(BP0618007).
文摘Tuning metal-support interactions(MSIs)is an important strategy in heterogeneous catalysis to realize the desirable metal dispersion and redox ability of metal catalysts.Herein,we use pre-reduced Co_(3)O_(4)nanowires(Co-NWs)in situ grown on monolithic Ni foam substrates to support Ag catalysts(Ag/Co-NW-R)for soot combustion.The macroporous structure of Ni foam with crossed Co_(3)O_(4)nanowires remarkably increases the soot-catalyst contact effi ciency.Our characterization results demonstrate that Ag species exist as Ag 0 because of the equation Ag^(+)+Co^(2+)=Ag^(0)+Co^(3+),and the pre-reduction treatment enhances interactions between Ag and Co_(3)O_(4).The number of active oxygen species on the Ag-loaded catalysts is approximately twice that on the supports,demonstrating the signifi cant role of Ag sites in generating active oxygen species.Additionally,the strengthened MSI on Ag/Co-NW-R further improves this number by increasing metal dispersion and the intrinsic activity determined by the turnover frequency of these oxygen species for soot oxidation compared with the catalyst without pre-reduction of Co-NW(Ag/Co-NW).In addition to high activity,Ag/Co-NW-R exhibits high catalytic stability and water resistance.The strategy used in this work might be applicable in related catalytic systems.
