Lithium metal batteries are regarded as prominent contenders to address the pressing needs owing to the high theoretical capacity.Toward the broader implementation,the primary obstacle lies in the intricate multi-elec...Lithium metal batteries are regarded as prominent contenders to address the pressing needs owing to the high theoretical capacity.Toward the broader implementation,the primary obstacle lies in the intricate multi-electron,multi-step redox reaction associated with sluggish conversion kinetics,subsequently giving rise to a cascade of parasitic issues.In order to smooth reaction kinetics,catalysts are widely introduced to accelerate reaction rate via modulating the energy barrier.Over past decades,a large amount of research has been devoted to the catalyst design and catalytic mechanism exploration,and thus the great progress in electrochemical performance has been realized.Therefore,it is necessary to make a comprehensive review toward key progress in catalyst design and future development pathway.In this review,the basic mechanism of lithium metal batteries is provided along with corresponding advantages and existing challenges detailly described.The main catalysts employed to accelerate cathode reaction with emphasis on their catalytic mechanism are summarized as well.Finally,the rational design and innovative direction toward efficient catalysts are suggested for future application in metal-sulfur/gas battery and beyond.This review is expected to drive and benefit future research on rational catalyst design with multi-parameter synergistic impacts on the activity and stability of next-generation metal battery,thus opening new avenue for sustainable solution to climate change,energy and environmental issues,and the potential industrial economy.展开更多
An efficient catalyst system based on a Pd-metalated porous organic polymer bearing phenanthroline ligands was designed and synthesized.This catalyst was applied to various C–C bond-forming reactions,including the Su...An efficient catalyst system based on a Pd-metalated porous organic polymer bearing phenanthroline ligands was designed and synthesized.This catalyst was applied to various C–C bond-forming reactions,including the Suzuki,Heck and Sonogashira couplings,and afforded the corresponding products while exhibiting excellent activities and selectivities.More importantly,this catalyst can be readily recycled.These features show that such catalysts have significant potential applications in the future.展开更多
separation is an attractive alternative to filtration or centrifugation for separating solid catalysts from a liquid phase, Here, core-shell Fe3O4@UiO-66-NH2 nanohybrids with well-defined structures were constructed b...separation is an attractive alternative to filtration or centrifugation for separating solid catalysts from a liquid phase, Here, core-shell Fe3O4@UiO-66-NH2 nanohybrids with well-defined structures were constructed by dispersing magnets in a dimethylformamide （DMF） solution con- taining two metal-organic framework （MOF） precursors, namely ZrCI4 and 2-aminobenzenetricar- boxylic acid. This method is simpler and more efficient than previously reported step-by-step method in which magnets were consecutively dispersed in DMF solutions each containing one MOF precursor, and the obtained Fe304@UiO-66-NH2 with three assembly cycles has a higher degree of crystallinity and porosiW. The core-shell Fe3O4@UiO-66-NH2 is highly active and selective in Knoevenagel condensations because of the bifunctionality of UiO-66-NH2 and better mass transfer in the nano-sized shells. It also has good recycling stability, and can be recovered magnetically and reused at least four times without significant loss of catalytic activity and framework integrity. The effects of substitution on the reactivity of benzaldehyde and of substrate size were also investigated.展开更多
The support of catalyst for the direct synthesis of diphenyl carbonate （DPC） by heterogeneous catalytic reaction was prepared by the sol-gel method. Compared with activated charcoal, molecular sieve, porous ceramics...The support of catalyst for the direct synthesis of diphenyl carbonate （DPC） by heterogeneous catalytic reaction was prepared by the sol-gel method. Compared with activated charcoal, molecular sieve, porous ceramics, hopcalite, the support prepared by the sol-gel method has higher activity. The characterization of the support by X-ray diffraction （XRD） and transmission electron microscope （TEM） show that the mare crystal phase is Co2MnO4 and the average particle diameter is about 40 nm. The optimum conditions for synthesis of the support were determined by orthogonal experiments, which indicate that the proportion of Cu, Mn, and Co is the first important factor influencing the yield and selectivity of DPC. Temperature of calcination is the second one. The optimum conditions are： molar proportion of Cu, Mn, and Co being 1 ： 1 ： 1, temperature of calcination 700℃, drying at 100~C, temperature of water bath 85~C. The yield and selectivity of DPC in the process can reach 38% and 99% in the batch operation, respectively. The copper cobalt manganese mixed oxides chosen as the support contribute more to the high catalytic activity than the sol-gel method.展开更多
TiO_2 nanoparticles（TiO_2 NPs） worked as an efficient heterogeneous catalyst in a one-pot,three-component,and solvent free Mannich reaction;producing variousβ-aminocarbonyls in good yields,and with good stereoselec...TiO_2 nanoparticles（TiO_2 NPs） worked as an efficient heterogeneous catalyst in a one-pot,three-component,and solvent free Mannich reaction;producing variousβ-aminocarbonyls in good yields,and with good stereoselectivities.The catalyst was easily separated from the reaction mixture and was recycled four times with no significant loss of its catalytic activity.展开更多
An efficient and direct procedure has been developed for the preparation of amidoalkyl naphthols by a one-pot condensation of aryl aldehydes, 2-naphthol and urea or amides, in the presence of HClO4-SiO2 as a heterogen...An efficient and direct procedure has been developed for the preparation of amidoalkyl naphthols by a one-pot condensation of aryl aldehydes, 2-naphthol and urea or amides, in the presence of HClO4-SiO2 as a heterogeneous catalyst. The reactions were carried out under reflux and solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, easy work-up and ecofriendly reaction condition. The catalyst is easily prepared, stable, reusable and efficient under the reaction conditions.展开更多
Self‐assembled mesoporous polyoxometalate‐based ionic hybrid catalyst,[PxyDim]2.5PMoV2,was prepared by combining p‐xylene‐tethered diimidazole ionic liquid[PxyDim]Cl2with Keggin‐structured V‐substituted polyoxom...Self‐assembled mesoporous polyoxometalate‐based ionic hybrid catalyst,[PxyDim]2.5PMoV2,was prepared by combining p‐xylene‐tethered diimidazole ionic liquid[PxyDim]Cl2with Keggin‐structured V‐substituted polyoxometalate H5PMo10V2O40.The obtained hybrid was shown to be a mesostructured and hydrophobic material with good thermal stability.In the H2O2‐based hydroxylation of benzene to phenol,the hybrid showed extraordinary catalytic activity and rate,and quite stable reusability.The unique hydrophobic properties and mesoporous structure of the hybrid were responsible for its excellent catalytic performance.展开更多
A double active center system, namely Salen-Cu（Ⅱ）@MIL-101（Cr）, was successfully synthesized via the"ship in a bottle" approach, which acted as a bifunctional material for both capture and conversion of ...A double active center system, namely Salen-Cu（Ⅱ）@MIL-101（Cr）, was successfully synthesized via the"ship in a bottle" approach, which acted as a bifunctional material for both capture and conversion of COin a single process. For the first time, Salen-Cu（Ⅱ）@MIL-101（Cr） catalyst was developed for the synthesis of propylene carbonate from COand propylene oxide under room temperature and ambient pressure with a yield of 87.8% over 60 h. Furthermore, the reaction mechanism was also discussed.展开更多
Safe, sustainable, and green production of hydro gen peroxide is an exciting proposition due to the role of hydrogen peroxide as a green oxidant and energy carrier for fuel cells. The current work reports the developm...Safe, sustainable, and green production of hydro gen peroxide is an exciting proposition due to the role of hydrogen peroxide as a green oxidant and energy carrier for fuel cells. The current work reports the development of carbon dot-impregnated waterborne hyperbranched polyurethane as a heterogeneous photo-catalyst for solar-driven production of hydrogen peroxide. The results reveal that the carbon dots possess a suitable band-gap of 2.98 eV,which facilitates effective splitting of both water and ethanol under solar irradiation. Inclusion of the carbon dots within the eco-friendly polymeric material ensures their catalytic activity and also provides a facile route for easy catalyst separation, especially from a solubilizing medium.The overall process was performed in accordance with the principles of green chemistry using bio-based precursorsand aqueous medium. This work highlights the potential of carbon dots as an effective photo-catalyst.展开更多
catalyst for the synthesis of 14-aryl- 14-H-dibenzo[aj]xanthenes Silica supported ammonium dihydrogen phosphate （NH4H2PO4/SiO2） is found to be a recyclable heterogeneous catalyst for a rapid and efficient synthesis ...catalyst for the synthesis of 14-aryl- 14-H-dibenzo[aj]xanthenes Silica supported ammonium dihydrogen phosphate （NH4H2PO4/SiO2） is found to be a recyclable heterogeneous catalyst for a rapid and efficient synthesis of various aryl-14-H-dibenzo[a,j]xanthenes with excellent yields under solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, short reaction times and milder conditions. 2009 Shahnaz Rostamizadeh. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
Solar‐driven conversion of carbon dioxide,water and nitrogen into high value‐added fuels(e.g.H_(2),CO,CH_(4),CH_(3)OH,NH_(3) and so on)is regarded as an environmental‐friendly and ideal route for relieving the gree...Solar‐driven conversion of carbon dioxide,water and nitrogen into high value‐added fuels(e.g.H_(2),CO,CH_(4),CH_(3)OH,NH_(3) and so on)is regarded as an environmental‐friendly and ideal route for relieving the greenhouse gas effect and countering energy crisis,which is an attractive and challenging topic.Hence,various types of photocatalysts have been developed successively to meet the requirements of these photocatalysis.Among them,cobalt‐based heterogeneous catalysts emerge as one of the most promising photocatalysts that open up alluring vistas in the field of solar‐to‐fuels conversion,which can effectively enhance photocatalytic efficiency by extending light absorption range,promoting charge separation,providing active sites,and lowering reaction barrier.In this review,we first present the working principles of cobalt‐based heterogeneous catalysts for photocatalytic water splitting,CO_(2) reduction,and N_(2) fixation.Second,five efficient strategies including surface modification,morphology modulation,crystallinity controlling,crystal engineering and doping,are discussed for improving the photocatalytic performance with different types cobalt‐based catalysts(cobalt nanoparticles and single atom,oxides,sulfides,phosphides,MOFs,COFs,LDHs,carbide,and nitrides).Third,we outline the applications for the state‐of‐the‐art photocatalytic CO_(2) reduction and water splitting,and nitrogen fixation over cobalt‐based heterogeneous catalysts.Finally,the central challenges and possible improvements of cobalt‐based photocatalysis in the future are presented.The purpose of this review is to summarize the past experience and lessons,and provide reference for the further development of cobalt‐based photocatalysis technology.展开更多
α, α＇-Benzylidene bis（4-hydroxycoumarin） derivatives were readily prepared in a few minutes with good yields through the reaction of an aromatic aldehyde and 4-hydroxycoumarin in aqueous media in the presence of ...α, α＇-Benzylidene bis（4-hydroxycoumarin） derivatives were readily prepared in a few minutes with good yields through the reaction of an aromatic aldehyde and 4-hydroxycoumarin in aqueous media in the presence of catalytic tris（hydrogensulfato） boron [B（HSO_4）_3].展开更多
Spherical polystyrene‐supported ammonium salts containing different linking chains between the support and ammonium groups were prepared as efficient and easily reusable heterogeneous catalysts for the cycloadditions...Spherical polystyrene‐supported ammonium salts containing different linking chains between the support and ammonium groups were prepared as efficient and easily reusable heterogeneous catalysts for the cycloadditions of CO2and epoxides.The effects of the length of the linking chains and a hydroxyl group pendent on the linking chain on the catalytic performance of ionic liquid immobilized catalysts and their mechanisms were studied through experiments and density functional theory calculations.It was found that,compared with a short linking chain,a long chain can make the halogen anion more negative and provide a larger contact area of the catalysts with the reactants,thus enhancing the reaction kinetics.The hydroxyl group can stretch the C-O bonds of the epoxides,promoting the reaction thermodynamics.As a result,for the cycloaddition of propylene oxide,the yield of propylene carbonate is much higher for the catalyst with a long linking chain(yield:91.4%)compared with the yield for that with a short chain(yield:70.9%),and is further increased in the presence of pendent hydroxyl groups(yield:98.5%).The catalyst also shows a high catalytic activity even at mild temperature and good reusability(yield:≥96%for10cycles),and the selectivity is always above99%.展开更多
For the paper industry, the disposal and management of the yielded sludge are a considerable challenge. In our work, the paper mill sludge-derived magnetically separable heterogeneous catalyst（PMS-Fe-380） was prepar...For the paper industry, the disposal and management of the yielded sludge are a considerable challenge. In our work, the paper mill sludge-derived magnetically separable heterogeneous catalyst（PMS-Fe-380） was prepared easily through a facile synthesis method. The morphology and structure of PMS-Fe-380 were fully characterized by means of X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmet–Teller analysis. The catalytic activity of PMS-Fe-380 was evaluated by degradation of Methylene Blue（MB）. The reusability and stability of PMS-Fe-380 were evaluated in five repeated runs, which suggested that PMS-Fe-380 manifested excellent stability of catalytic activity. Moreover,leaching tests indicated that the leached iron is negligible（〈0.5 mg/L）. This study provides an alternative environmentally friendly reuse method for paper mill sludge and a novel catalyst PMS-Fe-380 that can be considered as a promising heterogeneous Fenton-like catalyst.展开更多
Gluconic acid and its derivatives have been widely used in the food and pharmaceutical industries. Conventional processes that involve the conversion of glucose into gluconic acid via fermentation present several tech...Gluconic acid and its derivatives have been widely used in the food and pharmaceutical industries. Conventional processes that involve the conversion of glucose into gluconic acid via fermentation present several technological shortcomings as they involve energy-intensive wastewater treatment and complex enzyme separation. Greener oxidation processes over heterogeneous metal catalysts have attracted increasing attention worldwide. Au-, Pt-and Pd-based heterogeneous catalysts have been extensively used for the chemical oxidation of glucose to gluconic acid. Bimetallic catalysts synthesized by adding either noble or inexpensive metals have also presented excellent performance for the oxidations of glucose. In particular, particle size, which has been recognized as the most important factor that affect catalytic performances, could be rationally tuned by changing the types of support and ligand as well as the synthesis conditions. In this perspective review, we summarize and critically discuss the recent advances in the structural design of mono-and bimetallic catalysts for the oxidation of glucose in aqueous media. Furthermore, the challenges of developing catalysts for the green synthesis of gluconic acid have been highlighted. This review provides alternative insights for designing effective catalytic materials for the catalytic oxidation of bio-derived oxygenates over heterogeneous catalysts.展开更多
Co-salen functionalized on graphene with an average pore size of 27.7 nm as a heterogeneous catalyst exhibited good catalytic activity and recyclability in cyclohexene oxidation.
Heterogeneous transition metal catalysts are indispensable in improving environmental pollution.However,their fabrication is often costly and cumbersome,and they can easily pollute the environment.This study proposed ...Heterogeneous transition metal catalysts are indispensable in improving environmental pollution.However,their fabrication is often costly and cumbersome,and they can easily pollute the environment.This study proposed using a natural Gabonese ore(GBO)containing Mn_(x)O_(y) and FexOy as catalysts to degrade orange Ⅱ(OII)via peroxymonosulfate(PMS)activation.The GBO+PMS system exhibited extraordinarily high stability and catalytic activity towards OII elimination(92.2%,0.0453 min^(−1)).The reactive oxygen species(ROS)generated in the system were identified using radical scavenging tests and electron spin-resonance(ESR)analysis.Singlet oxygen(^(1)O_(2))represented the dominant reactive species for OII degradation,while the system presented a lower reaction energy barrier and was effective in a broad pH range(2-10).This work also proposed the activation mechanism for the GBO+PMS system and OII degradation pathways.This study revealed a new approach for exploring inexpensive,eco-friendly,efficient,and stable heterogeneous transition metal catalysts.展开更多
A highly efficient and general method for the synthesis of polyfunctionalized 4H-pyrans is established through a one-pot multicomponent cyclocondensation of aromatic aldehydes with CH acids, malononitrile and ethyl ac...A highly efficient and general method for the synthesis of polyfunctionalized 4H-pyrans is established through a one-pot multicomponent cyclocondensation of aromatic aldehydes with CH acids, malononitrile and ethyl acetoacetate using nano silica supported tin （II） chloride as a catalyst. In this method SnCl2/nano Si02 was used as green and reusable catalyst. Excellent yields, short reaction times, simple workup, and inexpensiveness and commercially availability of the catalyst are the advantages of this method.展开更多
A waste paper sludge-derived heterogeneous catalyst（WPS-Fe-350） was synthesized via a facile method and successfully applied for the degradation of Orange Ⅱ in the presence of oxalic acid under the illumination of ...A waste paper sludge-derived heterogeneous catalyst（WPS-Fe-350） was synthesized via a facile method and successfully applied for the degradation of Orange Ⅱ in the presence of oxalic acid under the illumination of ultraviolet light emitting diode（UV-LED） Powder X-ray diffraction,Fourier-transform infrared spectroscopy,scanning electronic microscopy and N2 sorption isotherm analysis indicated the formation of α-Fe2O3 in the mesoporous nanocomposite.The degradation test showed that WPS-Fe-350 exhibited rapid Orange Ⅱ（OⅡ） degradation and mineralization in the presence of oxalic acid under the illumination of UV-LED.The effects of p H,oxalic acid concentration and dosage of the catalyst on the degradation of OⅡ were evaluated,respectively.Under the optimal conditions（1 g/L catalyst dosage,2 mmol/L oxalic acid and p H 3.0）,the degradation percentage for a solution containing 30 mg/L OⅡ reached 83.4% under illumination by UV-LED for 80 min.Moreover,five cyclic tests for OⅡ degradation suggested that WPS-Fe-350 exhibited excellent stability of catalytic activity.Hence,this study provides an alternative environmentally friendly way to reuse waste paper sludge and an effective and economically viable method for degradation of azo dyes and other refractory organic pollutants in water.展开更多
In this work,the natural nanozeolite clinoptilolite（Nano CP） was successfully functionalized by propylsulfonic acid and applied as efficient heterogeneous catalyst for the synthesis of quinoxaline derivatives in aqu...In this work,the natural nanozeolite clinoptilolite（Nano CP） was successfully functionalized by propylsulfonic acid and applied as efficient heterogeneous catalyst for the synthesis of quinoxaline derivatives in aqueous media.The nanocatalyst was characterized by various techniques such as CHN,XRD,FT-IR,BET,TGA/DTA,SEM,TEM and TEM-EDS.The results show its applicability as green,reusable and promising catalyst in organic synthesis.It was found that the nanocatalysts could be recycled and reused eight times without significant loss of catalytic activities.展开更多
基金supported by the National Natural Science Foundation of China(52272194)Liaoning Revitalization Talents Program(XLYC2007155)。
文摘Lithium metal batteries are regarded as prominent contenders to address the pressing needs owing to the high theoretical capacity.Toward the broader implementation,the primary obstacle lies in the intricate multi-electron,multi-step redox reaction associated with sluggish conversion kinetics,subsequently giving rise to a cascade of parasitic issues.In order to smooth reaction kinetics,catalysts are widely introduced to accelerate reaction rate via modulating the energy barrier.Over past decades,a large amount of research has been devoted to the catalyst design and catalytic mechanism exploration,and thus the great progress in electrochemical performance has been realized.Therefore,it is necessary to make a comprehensive review toward key progress in catalyst design and future development pathway.In this review,the basic mechanism of lithium metal batteries is provided along with corresponding advantages and existing challenges detailly described.The main catalysts employed to accelerate cathode reaction with emphasis on their catalytic mechanism are summarized as well.Finally,the rational design and innovative direction toward efficient catalysts are suggested for future application in metal-sulfur/gas battery and beyond.This review is expected to drive and benefit future research on rational catalyst design with multi-parameter synergistic impacts on the activity and stability of next-generation metal battery,thus opening new avenue for sustainable solution to climate change,energy and environmental issues,and the potential industrial economy.
基金supported by the National Natural Foundation of China(21422306,21203165,21403193)the Fundamental Research Funds for the Central Universities(2015XZZX004-04)~~
文摘An efficient catalyst system based on a Pd-metalated porous organic polymer bearing phenanthroline ligands was designed and synthesized.This catalyst was applied to various C–C bond-forming reactions,including the Suzuki,Heck and Sonogashira couplings,and afforded the corresponding products while exhibiting excellent activities and selectivities.More importantly,this catalyst can be readily recycled.These features show that such catalysts have significant potential applications in the future.
基金supported by the National Natural Science Foundation of China (21203017)Open Fund of State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences (N-11-3)+1 种基金Program for Liaoning Excellent Talents in University (LNET)the Funda-mental Research Funds for the Central Universities (DC201502020304)~~
文摘separation is an attractive alternative to filtration or centrifugation for separating solid catalysts from a liquid phase, Here, core-shell Fe3O4@UiO-66-NH2 nanohybrids with well-defined structures were constructed by dispersing magnets in a dimethylformamide （DMF） solution con- taining two metal-organic framework （MOF） precursors, namely ZrCI4 and 2-aminobenzenetricar- boxylic acid. This method is simpler and more efficient than previously reported step-by-step method in which magnets were consecutively dispersed in DMF solutions each containing one MOF precursor, and the obtained Fe304@UiO-66-NH2 with three assembly cycles has a higher degree of crystallinity and porosiW. The core-shell Fe3O4@UiO-66-NH2 is highly active and selective in Knoevenagel condensations because of the bifunctionality of UiO-66-NH2 and better mass transfer in the nano-sized shells. It also has good recycling stability, and can be recovered magnetically and reused at least four times without significant loss of catalytic activity and framework integrity. The effects of substitution on the reactivity of benzaldehyde and of substrate size were also investigated.
文摘The support of catalyst for the direct synthesis of diphenyl carbonate （DPC） by heterogeneous catalytic reaction was prepared by the sol-gel method. Compared with activated charcoal, molecular sieve, porous ceramics, hopcalite, the support prepared by the sol-gel method has higher activity. The characterization of the support by X-ray diffraction （XRD） and transmission electron microscope （TEM） show that the mare crystal phase is Co2MnO4 and the average particle diameter is about 40 nm. The optimum conditions for synthesis of the support were determined by orthogonal experiments, which indicate that the proportion of Cu, Mn, and Co is the first important factor influencing the yield and selectivity of DPC. Temperature of calcination is the second one. The optimum conditions are： molar proportion of Cu, Mn, and Co being 1 ： 1 ： 1, temperature of calcination 700℃, drying at 100~C, temperature of water bath 85~C. The yield and selectivity of DPC in the process can reach 38% and 99% in the batch operation, respectively. The copper cobalt manganese mixed oxides chosen as the support contribute more to the high catalytic activity than the sol-gel method.
文摘TiO_2 nanoparticles（TiO_2 NPs） worked as an efficient heterogeneous catalyst in a one-pot,three-component,and solvent free Mannich reaction;producing variousβ-aminocarbonyls in good yields,and with good stereoselectivities.The catalyst was easily separated from the reaction mixture and was recycled four times with no significant loss of its catalytic activity.
文摘An efficient and direct procedure has been developed for the preparation of amidoalkyl naphthols by a one-pot condensation of aryl aldehydes, 2-naphthol and urea or amides, in the presence of HClO4-SiO2 as a heterogeneous catalyst. The reactions were carried out under reflux and solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, easy work-up and ecofriendly reaction condition. The catalyst is easily prepared, stable, reusable and efficient under the reaction conditions.
基金supported by the National Natural Science Foundation of China (21506118,21476132,51574160)Shandong Province Founda-tion for Outstanding Young Scientist (BS2014CL030)~~
文摘Self‐assembled mesoporous polyoxometalate‐based ionic hybrid catalyst,[PxyDim]2.5PMoV2,was prepared by combining p‐xylene‐tethered diimidazole ionic liquid[PxyDim]Cl2with Keggin‐structured V‐substituted polyoxometalate H5PMo10V2O40.The obtained hybrid was shown to be a mesostructured and hydrophobic material with good thermal stability.In the H2O2‐based hydroxylation of benzene to phenol,the hybrid showed extraordinary catalytic activity and rate,and quite stable reusability.The unique hydrophobic properties and mesoporous structure of the hybrid were responsible for its excellent catalytic performance.
基金supported by the National Key Projects for Fundamental R&D Program of China(2016YFB0600902)the NFSC of Tianjin(16JCZDJC36700 and 14JCQNJC03000)
文摘A double active center system, namely Salen-Cu（Ⅱ）@MIL-101（Cr）, was successfully synthesized via the"ship in a bottle" approach, which acted as a bifunctional material for both capture and conversion of COin a single process. For the first time, Salen-Cu（Ⅱ）@MIL-101（Cr） catalyst was developed for the synthesis of propylene carbonate from COand propylene oxide under room temperature and ambient pressure with a yield of 87.8% over 60 h. Furthermore, the reaction mechanism was also discussed.
基金DBT(Grant No.BT/235/NE/TBP/2011 Dated April 30,2012),India,for financial support
文摘Safe, sustainable, and green production of hydro gen peroxide is an exciting proposition due to the role of hydrogen peroxide as a green oxidant and energy carrier for fuel cells. The current work reports the development of carbon dot-impregnated waterborne hyperbranched polyurethane as a heterogeneous photo-catalyst for solar-driven production of hydrogen peroxide. The results reveal that the carbon dots possess a suitable band-gap of 2.98 eV,which facilitates effective splitting of both water and ethanol under solar irradiation. Inclusion of the carbon dots within the eco-friendly polymeric material ensures their catalytic activity and also provides a facile route for easy catalyst separation, especially from a solubilizing medium.The overall process was performed in accordance with the principles of green chemistry using bio-based precursorsand aqueous medium. This work highlights the potential of carbon dots as an effective photo-catalyst.
文摘catalyst for the synthesis of 14-aryl- 14-H-dibenzo[aj]xanthenes Silica supported ammonium dihydrogen phosphate （NH4H2PO4/SiO2） is found to be a recyclable heterogeneous catalyst for a rapid and efficient synthesis of various aryl-14-H-dibenzo[a,j]xanthenes with excellent yields under solvent-free conditions. The present methodology offers several advantages such as excellent yields, simple procedure, short reaction times and milder conditions. 2009 Shahnaz Rostamizadeh. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
文摘Solar‐driven conversion of carbon dioxide,water and nitrogen into high value‐added fuels(e.g.H_(2),CO,CH_(4),CH_(3)OH,NH_(3) and so on)is regarded as an environmental‐friendly and ideal route for relieving the greenhouse gas effect and countering energy crisis,which is an attractive and challenging topic.Hence,various types of photocatalysts have been developed successively to meet the requirements of these photocatalysis.Among them,cobalt‐based heterogeneous catalysts emerge as one of the most promising photocatalysts that open up alluring vistas in the field of solar‐to‐fuels conversion,which can effectively enhance photocatalytic efficiency by extending light absorption range,promoting charge separation,providing active sites,and lowering reaction barrier.In this review,we first present the working principles of cobalt‐based heterogeneous catalysts for photocatalytic water splitting,CO_(2) reduction,and N_(2) fixation.Second,five efficient strategies including surface modification,morphology modulation,crystallinity controlling,crystal engineering and doping,are discussed for improving the photocatalytic performance with different types cobalt‐based catalysts(cobalt nanoparticles and single atom,oxides,sulfides,phosphides,MOFs,COFs,LDHs,carbide,and nitrides).Third,we outline the applications for the state‐of‐the‐art photocatalytic CO_(2) reduction and water splitting,and nitrogen fixation over cobalt‐based heterogeneous catalysts.Finally,the central challenges and possible improvements of cobalt‐based photocatalysis in the future are presented.The purpose of this review is to summarize the past experience and lessons,and provide reference for the further development of cobalt‐based photocatalysis technology.
文摘α, α＇-Benzylidene bis（4-hydroxycoumarin） derivatives were readily prepared in a few minutes with good yields through the reaction of an aromatic aldehyde and 4-hydroxycoumarin in aqueous media in the presence of catalytic tris（hydrogensulfato） boron [B（HSO_4）_3].
基金supported by the National Natural Science Foundation of China(21406031,21476044,U1663223)the Changjiang Scholars Program(T2012049)+3 种基金the State Key Laboratory of Fine Chemicals(KF1507)Dalian High-Level Talent Support Program(2015R056)Education Department of the Liaoning Province of China(LT2015007)Fundamental Research Funds for the Central Universities(DUT16TD19)~~
文摘Spherical polystyrene‐supported ammonium salts containing different linking chains between the support and ammonium groups were prepared as efficient and easily reusable heterogeneous catalysts for the cycloadditions of CO2and epoxides.The effects of the length of the linking chains and a hydroxyl group pendent on the linking chain on the catalytic performance of ionic liquid immobilized catalysts and their mechanisms were studied through experiments and density functional theory calculations.It was found that,compared with a short linking chain,a long chain can make the halogen anion more negative and provide a larger contact area of the catalysts with the reactants,thus enhancing the reaction kinetics.The hydroxyl group can stretch the C-O bonds of the epoxides,promoting the reaction thermodynamics.As a result,for the cycloaddition of propylene oxide,the yield of propylene carbonate is much higher for the catalyst with a long linking chain(yield:91.4%)compared with the yield for that with a short chain(yield:70.9%),and is further increased in the presence of pendent hydroxyl groups(yield:98.5%).The catalyst also shows a high catalytic activity even at mild temperature and good reusability(yield:≥96%for10cycles),and the selectivity is always above99%.
基金supported by the Major Science and Technology Projects Focus on Social Development Projects of Zhejiang Province (Nos. 2014C03002 and 2012C03004-1)
文摘For the paper industry, the disposal and management of the yielded sludge are a considerable challenge. In our work, the paper mill sludge-derived magnetically separable heterogeneous catalyst（PMS-Fe-380） was prepared easily through a facile synthesis method. The morphology and structure of PMS-Fe-380 were fully characterized by means of X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and Brunauer–Emmet–Teller analysis. The catalytic activity of PMS-Fe-380 was evaluated by degradation of Methylene Blue（MB）. The reusability and stability of PMS-Fe-380 were evaluated in five repeated runs, which suggested that PMS-Fe-380 manifested excellent stability of catalytic activity. Moreover,leaching tests indicated that the leached iron is negligible（〈0.5 mg/L）. This study provides an alternative environmentally friendly reuse method for paper mill sludge and a novel catalyst PMS-Fe-380 that can be considered as a promising heterogeneous Fenton-like catalyst.
文摘Gluconic acid and its derivatives have been widely used in the food and pharmaceutical industries. Conventional processes that involve the conversion of glucose into gluconic acid via fermentation present several technological shortcomings as they involve energy-intensive wastewater treatment and complex enzyme separation. Greener oxidation processes over heterogeneous metal catalysts have attracted increasing attention worldwide. Au-, Pt-and Pd-based heterogeneous catalysts have been extensively used for the chemical oxidation of glucose to gluconic acid. Bimetallic catalysts synthesized by adding either noble or inexpensive metals have also presented excellent performance for the oxidations of glucose. In particular, particle size, which has been recognized as the most important factor that affect catalytic performances, could be rationally tuned by changing the types of support and ligand as well as the synthesis conditions. In this perspective review, we summarize and critically discuss the recent advances in the structural design of mono-and bimetallic catalysts for the oxidation of glucose in aqueous media. Furthermore, the challenges of developing catalysts for the green synthesis of gluconic acid have been highlighted. This review provides alternative insights for designing effective catalytic materials for the catalytic oxidation of bio-derived oxygenates over heterogeneous catalysts.
基金the National Natural Science Foundation of China(20973079 and U1162201)Graduate Innovation Fund of Jilin University(20121051)
文摘Co-salen functionalized on graphene with an average pore size of 27.7 nm as a heterogeneous catalyst exhibited good catalytic activity and recyclability in cyclohexene oxidation.
基金funding support from Talent Introduction Program of Xihua University(No.Z202117)。
文摘Heterogeneous transition metal catalysts are indispensable in improving environmental pollution.However,their fabrication is often costly and cumbersome,and they can easily pollute the environment.This study proposed using a natural Gabonese ore(GBO)containing Mn_(x)O_(y) and FexOy as catalysts to degrade orange Ⅱ(OII)via peroxymonosulfate(PMS)activation.The GBO+PMS system exhibited extraordinarily high stability and catalytic activity towards OII elimination(92.2%,0.0453 min^(−1)).The reactive oxygen species(ROS)generated in the system were identified using radical scavenging tests and electron spin-resonance(ESR)analysis.Singlet oxygen(^(1)O_(2))represented the dominant reactive species for OII degradation,while the system presented a lower reaction energy barrier and was effective in a broad pH range(2-10).This work also proposed the activation mechanism for the GBO+PMS system and OII degradation pathways.This study revealed a new approach for exploring inexpensive,eco-friendly,efficient,and stable heterogeneous transition metal catalysts.
基金University of Kashan for supporting this work by Grant No.159196/XV
文摘A highly efficient and general method for the synthesis of polyfunctionalized 4H-pyrans is established through a one-pot multicomponent cyclocondensation of aromatic aldehydes with CH acids, malononitrile and ethyl acetoacetate using nano silica supported tin （II） chloride as a catalyst. In this method SnCl2/nano Si02 was used as green and reusable catalyst. Excellent yields, short reaction times, simple workup, and inexpensiveness and commercially availability of the catalyst are the advantages of this method.
基金supported by the Major Science and Technology Projects Focus on Social Development Projects of Zhejiang Province(Nos.2014C03002 and 2012C03004-1)
文摘A waste paper sludge-derived heterogeneous catalyst（WPS-Fe-350） was synthesized via a facile method and successfully applied for the degradation of Orange Ⅱ in the presence of oxalic acid under the illumination of ultraviolet light emitting diode（UV-LED） Powder X-ray diffraction,Fourier-transform infrared spectroscopy,scanning electronic microscopy and N2 sorption isotherm analysis indicated the formation of α-Fe2O3 in the mesoporous nanocomposite.The degradation test showed that WPS-Fe-350 exhibited rapid Orange Ⅱ（OⅡ） degradation and mineralization in the presence of oxalic acid under the illumination of UV-LED.The effects of p H,oxalic acid concentration and dosage of the catalyst on the degradation of OⅡ were evaluated,respectively.Under the optimal conditions（1 g/L catalyst dosage,2 mmol/L oxalic acid and p H 3.0）,the degradation percentage for a solution containing 30 mg/L OⅡ reached 83.4% under illumination by UV-LED for 80 min.Moreover,five cyclic tests for OⅡ degradation suggested that WPS-Fe-350 exhibited excellent stability of catalytic activity.Hence,this study provides an alternative environmentally friendly way to reuse waste paper sludge and an effective and economically viable method for degradation of azo dyes and other refractory organic pollutants in water.
基金supported by the Islamic Azad University, Ayatollah Amoli Branch,I.R.Iran
文摘In this work,the natural nanozeolite clinoptilolite（Nano CP） was successfully functionalized by propylsulfonic acid and applied as efficient heterogeneous catalyst for the synthesis of quinoxaline derivatives in aqueous media.The nanocatalyst was characterized by various techniques such as CHN,XRD,FT-IR,BET,TGA/DTA,SEM,TEM and TEM-EDS.The results show its applicability as green,reusable and promising catalyst in organic synthesis.It was found that the nanocatalysts could be recycled and reused eight times without significant loss of catalytic activities.
