Ordered metal oxides superstructures have attracted much more attention in the fields of fuel generation and environmental purification owing to their unique physiochemical characteristics such as large surface area, ...Ordered metal oxides superstructures have attracted much more attention in the fields of fuel generation and environmental purification owing to their unique physiochemical characteristics such as large surface area, fine pore structure, efficient electronic mobility, and good stability. Very recently, TiOmesocrystals（TMCs） having superstructures self-assembled by TiOnanoparticle building blocks, are of considerable interest in current research and application ranging from UV to visible light attributed to their efficient charge separation and superior photocatalytic activity. In this review, we describe the common procedures to prepare unique TMCs and overview of recent developments of TMCs during last 3 years, especially the structure-related or electronic-effected mechanism in photocatalytic reaction. Further, we introduce the characterization and fundamental properties of modified TMCs by the means of single-particle fluorescence microscopy for unraveling the charge transport and photocatalytic properties of individual TMCs and time-resolved diffuse reflectance spectroscopy（TDR） for monitoring the charge transfer dynamics. Finally, various aspects on TMCs are discussed for the future developments of energy and environmental fields.展开更多
During last two decades,transition-metal catalyzed asymmetric reactions under continuous flow system have attracted a widespread attention.With its prominent advantages including higher safety and efficiency,precise c...During last two decades,transition-metal catalyzed asymmetric reactions under continuous flow system have attracted a widespread attention.With its prominent advantages including higher safety and efficiency,precise control,better heat/mass transfer,easier scale-up and better sustainability,it has impressed both the academia and related industries.However,comparing with the prosperous development of transition-metal catalyzed asymmetric reactions in batch,utilization of this type of chemistry under continuous flow is still at an early stage.To inspire more potential industrial application and further studies of this chemistry in flow,this review sum-marized the recent advances of transition-metal catalyzed asymmetric reactions under continuous flow.Moreover,we further discussed the encountered challenges including reactor engineering,catalyst design,catalyst deacti-vation,pressure drop,clogging,side reactions etc.,as well as their corresponding solutions and achievements in this mini-review.展开更多
Realizing fast and continuous generation of reactive oxygen species(ROSs)via iron-based advanced oxidation processes(AOPs)is significant in the environmental and biological fields.However,current AOPs assisted by co-c...Realizing fast and continuous generation of reactive oxygen species(ROSs)via iron-based advanced oxidation processes(AOPs)is significant in the environmental and biological fields.However,current AOPs assisted by co-catalysts still suffer from the poor mass/electron transfer and non-durable promotion effect,giving rise to the sluggish Fe^(2+)/Fe^(3+)cycle and low dynamic concentration of Fe^(2+)for ROS production.Herein,we present a three-dimensional(3D)macroscale co-catalyst functionalized with molybdenum disulfide(MoS_(2))to achieve ultra-efficient Fe^(2+)regeneration(equilibrium Fe^(2+)ratio of 82.4%)and remarkable stability(more than 20 cycles)via a circulating flow-through process.Unlike the conventional batch-type reactor,experiments and computational fluid dynamics simulations demonstrate that the optimal utilization of the 3D active area under the flow-through mode,initiated by the convectionenhanced mass/charge transfer for Fe^(2+)reduction and then strengthened by MoS_(2)-induced flow rotation for sufficient reactant mixing,is crucial for oxidant activation and subsequent ROS generation.Strikingly,the flow-through co-catalytic system with superwetting capabilities can even tackle the intricate oily wastewater stabilized by different surfactants without the loss of pollutant degradation efficiency.Our findings highlight an innovative co-catalyst system design to expand the applicability of AOPs based technology,especially in large-scale complex wastewater treatment.展开更多
Replacing fossil carbon sources with green bio-oils is a promising route to switch to a sustainable chemical industry,although their high oxygen contents are challenging.Catalytic hydrodeoxygenation is a favored route...Replacing fossil carbon sources with green bio-oils is a promising route to switch to a sustainable chemical industry,although their high oxygen contents are challenging.Catalytic hydrodeoxygenation is a favored route to upgrade bio-oils to renewable fuels and basic chemicals.In this work,we investigated Ni/SiO2 catalysts with differing metal dispersity in continuous mode conversion of guaiacol with a statistical experimental design for 250℃to 400℃,2 h up to 5 h time on stream(ToS)and subsequently different residence time besides other parameters.While low temperature(250℃)promotes cyclohexanol formation from guaiacol,high temperature(400℃)inhibits hydrogenation,leading to phenol and methane.For medium temperature(340℃),the selectivity for cyclohexanone increases.Cyclohexanol and cyclohexanone(KA-oil)are the industrial basis for polyamide 6.Furthermore,we clarified the role of 2-methoxycyclohexanol(2MC)in the reaction network towards KA-oil for continuous-mode operation.Statistical analysis was used to predict and optimize product selectivity and yield,leading to the best yield of cyclohexanone/-ol at 327.5℃,low ToS,medium residence time,high particle dispersity,and medium hydrogen pressure(15 bar(g)).展开更多
基金supported by a grant-in-aid for Scientific Research (Project 25220806 and others) from the Ministry of Education,Culture,Sports,Science and Technology (MEXT) of the Japanese Government
文摘Ordered metal oxides superstructures have attracted much more attention in the fields of fuel generation and environmental purification owing to their unique physiochemical characteristics such as large surface area, fine pore structure, efficient electronic mobility, and good stability. Very recently, TiOmesocrystals（TMCs） having superstructures self-assembled by TiOnanoparticle building blocks, are of considerable interest in current research and application ranging from UV to visible light attributed to their efficient charge separation and superior photocatalytic activity. In this review, we describe the common procedures to prepare unique TMCs and overview of recent developments of TMCs during last 3 years, especially the structure-related or electronic-effected mechanism in photocatalytic reaction. Further, we introduce the characterization and fundamental properties of modified TMCs by the means of single-particle fluorescence microscopy for unraveling the charge transport and photocatalytic properties of individual TMCs and time-resolved diffuse reflectance spectroscopy（TDR） for monitoring the charge transfer dynamics. Finally, various aspects on TMCs are discussed for the future developments of energy and environmental fields.
基金This work is supported by Shenzhen Fundamental Research Projects(No.JCYJ20190806142203709)We are also grateful to the startup of Harbin Institute of Technology(Shenzhen)through the Talent Development Starting Fund from Shenzhen Government(No.HA11409030).
文摘During last two decades,transition-metal catalyzed asymmetric reactions under continuous flow system have attracted a widespread attention.With its prominent advantages including higher safety and efficiency,precise control,better heat/mass transfer,easier scale-up and better sustainability,it has impressed both the academia and related industries.However,comparing with the prosperous development of transition-metal catalyzed asymmetric reactions in batch,utilization of this type of chemistry under continuous flow is still at an early stage.To inspire more potential industrial application and further studies of this chemistry in flow,this review sum-marized the recent advances of transition-metal catalyzed asymmetric reactions under continuous flow.Moreover,we further discussed the encountered challenges including reactor engineering,catalyst design,catalyst deacti-vation,pressure drop,clogging,side reactions etc.,as well as their corresponding solutions and achievements in this mini-review.
基金supported by National Natural Science Foundation of China(52003240)Zhejiang Provincial Natural Science Foundation of China(LQ21B070007)China Postdoctoral Science Foundation(2022M722818).
文摘Realizing fast and continuous generation of reactive oxygen species(ROSs)via iron-based advanced oxidation processes(AOPs)is significant in the environmental and biological fields.However,current AOPs assisted by co-catalysts still suffer from the poor mass/electron transfer and non-durable promotion effect,giving rise to the sluggish Fe^(2+)/Fe^(3+)cycle and low dynamic concentration of Fe^(2+)for ROS production.Herein,we present a three-dimensional(3D)macroscale co-catalyst functionalized with molybdenum disulfide(MoS_(2))to achieve ultra-efficient Fe^(2+)regeneration(equilibrium Fe^(2+)ratio of 82.4%)and remarkable stability(more than 20 cycles)via a circulating flow-through process.Unlike the conventional batch-type reactor,experiments and computational fluid dynamics simulations demonstrate that the optimal utilization of the 3D active area under the flow-through mode,initiated by the convectionenhanced mass/charge transfer for Fe^(2+)reduction and then strengthened by MoS_(2)-induced flow rotation for sufficient reactant mixing,is crucial for oxidant activation and subsequent ROS generation.Strikingly,the flow-through co-catalytic system with superwetting capabilities can even tackle the intricate oily wastewater stabilized by different surfactants without the loss of pollutant degradation efficiency.Our findings highlight an innovative co-catalyst system design to expand the applicability of AOPs based technology,especially in large-scale complex wastewater treatment.
基金supported by the Chair of Inorganic Molecular Chemistry(TU Dresden)by Prof.Dr.Jan J.Weigand.Evonik AG provided the silica carrier material Aerosil380 for research purposesThe Federal State of Saxony(Germany)funded the first author’s work through the Saxon State Scholarship ProgramThe corresponding author thanks German Research Foundation(DFG)for funding of project SE 2450/2-1(Nbr.507997100).
文摘Replacing fossil carbon sources with green bio-oils is a promising route to switch to a sustainable chemical industry,although their high oxygen contents are challenging.Catalytic hydrodeoxygenation is a favored route to upgrade bio-oils to renewable fuels and basic chemicals.In this work,we investigated Ni/SiO2 catalysts with differing metal dispersity in continuous mode conversion of guaiacol with a statistical experimental design for 250℃to 400℃,2 h up to 5 h time on stream(ToS)and subsequently different residence time besides other parameters.While low temperature(250℃)promotes cyclohexanol formation from guaiacol,high temperature(400℃)inhibits hydrogenation,leading to phenol and methane.For medium temperature(340℃),the selectivity for cyclohexanone increases.Cyclohexanol and cyclohexanone(KA-oil)are the industrial basis for polyamide 6.Furthermore,we clarified the role of 2-methoxycyclohexanol(2MC)in the reaction network towards KA-oil for continuous-mode operation.Statistical analysis was used to predict and optimize product selectivity and yield,leading to the best yield of cyclohexanone/-ol at 327.5℃,low ToS,medium residence time,high particle dispersity,and medium hydrogen pressure(15 bar(g)).
