With the increasing demand for scalable and cost-effective electrochemical energy storage,aqueous zinc ion batteries(AZIBs)have a broad application prospect as an inexpensive,efficient,and naturally secure energy stor...With the increasing demand for scalable and cost-effective electrochemical energy storage,aqueous zinc ion batteries(AZIBs)have a broad application prospect as an inexpensive,efficient,and naturally secure energy storage device.However,the limitations suffered by AZIBs,including volume expansion and active materials dissolution of the cathode,electrochemical corrosion,irreversible side reactions,zinc dendrites of the anode,have seriously decelerated the civilianization process of AZIBs.Currently,polymers have tremendous superiority for application in AZIBs attributed to their exceptional chemical stability,tunable structure,high energy density and outstanding mechanical properties.Considering the expanding applications of AZIBs and the superiority of polymers,this comprehensive paper meticulously reviews the benefits of utilizing polymeric applied to cathodes and anodes,respectively.To begin with,with adjustable structure as an entry point,the correlation between polymer structure and the function of energy storage as well as optimization is deeply investigated in respect to the mechanism.Then,depending on the diversity of properties and structures,the development of polymers in AZIBs is summarized,including conductive polymers,redox polymers as well as carbon composite polymers for cathode and polyvinylidene fluoride-,carbonyl-,amino-,nitrile-based polymers for anode,and a comprehensive evaluation of the shortcomings of these strategies is provided.Finally,an outlook highlights some of the challenges posed by the application of polymers and offers insights into the potential future direction of polymers in AZIBs.It is designed to provide a thorough reference for researchers and developers working on polymer for AZIBs.展开更多
1 Introduction Magnesium salts are very important by-product of salt lake industry in West China.Nearly 200 million cubic meters of waste brine are released to the environment
Single atomic catalysts(SACs),especially metal-nitrogen doped carbon(M-NC)catalysts,have been extensively explored for the electrochemical oxygen reduction reaction(ORR),owing to their high activity and atomic utiliza...Single atomic catalysts(SACs),especially metal-nitrogen doped carbon(M-NC)catalysts,have been extensively explored for the electrochemical oxygen reduction reaction(ORR),owing to their high activity and atomic utilization efficiency.However,there is still a lack of systematic screening and optimization of local structures surrounding active centers of SACs for ORR as the local coordination has an essential impact on their electronic structures and catalytic performance.Herein,we systematic study the ORR catalytic performance of M-NC SACs with different central metals and environmental atoms in the first and second coordination sphere by using density functional theory(DFT)calculation and machine learning(ML).The geometric and electronic informed overpotential model(GEIOM)based on random forest algorithm showed the highest accuracy,and its R^(2) and root mean square errors(RMSE)were 0.96 and 0.21,respectively.30 potential high-performance catalysts were screened out by GEIOM,and the RMSE of the predicted result was only 0.12 V.This work not only helps us fast screen high-performance catalysts,but also provides a low-cost way to improve the accuracy of ML models.展开更多
Adsorptive removal of heavy metal ions from wastewater is very important,and the key is the development of efficient sorbents.In this work,oxygenated alkynyl carbon materials(OACMs)were synthesized via mechanochemical...Adsorptive removal of heavy metal ions from wastewater is very important,and the key is the development of efficient sorbents.In this work,oxygenated alkynyl carbon materials(OACMs)were synthesized via mechanochemical reaction of CaC_(2) and a carbonate(CaCO_(3),Na2CO_(3),or NaHCO_(3))at ambient temperature.The resultant OACMs are micro mesoporous carbon nanomaterials with high specific area(>648 m2 g^(-1)),highly crosslinked texture,and rich alkynyl and oxygenated groups.The OACMs exhibit excellent Hg(Ⅱ)adsorption due to the soft acid-soft base interaction between alkynyl and Hg(Ⅱ),and OACM-3 derived from CaC_(2) and NaHCO_(3) has the saturated Hg(Ⅱ)adsorbance of 483.9 mg g^(-1)along with good selectivity and recyclability.The adsorption is mainly chemisorption following the Langmuir mode.OACM-3 also shows high adsorbance for other heavy metal ions,e.g.256.6 mg g^(-1)for Pb(II),232.4 mg g^(-1)for Zn(II),and 198.7 mg g^(-1)for Cu(II).This work expands the mechnochemical reaction of CaC_(2)with carbonates and possibly other oxyanionic salts,provides a new synthesis approach for functional alkynyl carbon materials with excellent adsorption performance for heavy metal ions,as well as a feasible approach for CO2 resource utilization.展开更多
The exploration of sustainable energy utilization requires the imple-mentation of advanced electrochemical devices for efficient energy conversion and storage,which are enabled by the usage of cost-effective,high-perf...The exploration of sustainable energy utilization requires the imple-mentation of advanced electrochemical devices for efficient energy conversion and storage,which are enabled by the usage of cost-effective,high-performance electro-catalysts.Currently,heterogeneous atomically dispersed catalysts are considered as potential candidates for a wide range of applications.Compared to conventional cata-lysts,atomically dispersed metal atoms in carbon-based catalysts have more unsatu-rated coordination sites,quantum size effect,and strong metal-support interactions,resulting in exceptional catalytic activity.Of these,dual-atomic catalysts(DACs)have attracted extensive attention due to the additional synergistic effect between two adja-cent metal atoms.DACs have the advantages of full active site exposure,high selectiv-ity,theoretical 100%atom utilization,and the ability to break the scaling relationship of adsorption free energy on active sites.In this review,we summarize recent research advancement of DACs,which includes(1)the comprehensive understanding of the synergy between atomic pairs;(2)the synthesis of DACs;(3)characterization meth-ods,especially aberration-corrected scanning transmission electron microscopy and synchrotron spectroscopy;and(4)electrochemical energy-related applications.The last part focuses on great potential for the electrochemical catalysis of energy-related small molecules,such as oxygen reduction reaction,CO_(2) reduction reaction,hydrogen evolution reaction,and N_(2) reduction reaction.The future research challenges and opportunities are also raised in prospective section.展开更多
Latex wastewater is a kind of refractory organic wastewater containing high concentrations of organics and ammonia nitrogen.In this work,the combined process of forward osmosis(FO)and reverse osmosis(RO)was designed t...Latex wastewater is a kind of refractory organic wastewater containing high concentrations of organics and ammonia nitrogen.In this work,the combined process of forward osmosis(FO)and reverse osmosis(RO)was designed to treat the latex wastewater in the whole process,achieving the water recovery rate of 99%and basically no waste discharge after the catalytic oxidation process.The turbidity of the latex wastewater was decreased to below 1 NTU by microfiltration pretreatment,and then using MgCl_2 worked as the draw solution for FO process to treat the latex wastewater.Different operation conditions including adding acid or scale inhibitor as the pretreatment methods were conducted to improve the treatment performance of the combined process.After the treatment of the whole process,the concentration of COD was less than 20 mg·L^(-1),the concentration of NH_3-N was less than 10 mg·L^(-1),and the concentration of TP was less than 0.5 mg·L^(-1)for the treated latex wastewater.The water quality met standards of industrial water reuse after the complete analysis of the treated latex wastewater,meanwhile,useful substances of L-Quebrachitol(L-Q)were successfully extracted from the concentrated solution.Therefore,the combined process of FO and RO could realize the efficient treatment and reuse of latex wastewater,which provided with some important guidance on the industrial application.展开更多
Glycerol carbonate,an important glycerol value-added product,has been widely used as an active intermediate and inert solvent in the synthesis of cosmetics,detergents,chemical intermediates,polymers,and so on.The dire...Glycerol carbonate,an important glycerol value-added product,has been widely used as an active intermediate and inert solvent in the synthesis of cosmetics,detergents,chemical intermediates,polymers,and so on.The direct carbonylation from glycerol with CO_(2)is considered a promising route,but still tough work due to the thermodynamic stability and the kinetic inertness of CO_(2).In this work,highlyselective direct carbonylation of glycerol and CO_(2)into glycerol carbonate has been achieved over highly dispersed MgInCe-mixed metal oxides(MgInCe-MMO),which were prepared through the topological transformation derived from the MgInCe-layered double hydroxides(MgInCe-LDHs).By precisely modulating the surface basic-acidic properties and the oxygen vacancies,an efficient carbonylation of glycerol with CO_(2)has been achieved with a selectivity of up to>99%to glycerol carbonate.Deep investigation into the synergistic catalysis of base-acid sites and oxygen vacancies has been clarified.展开更多
A transformation of naphthalene-based coalescenced mesophase pitch(NMP)to mesophase microbeads was achieved by heating a mixture of NMP and fullerene(C_(60)).This is different from the conventional process of the liqu...A transformation of naphthalene-based coalescenced mesophase pitch(NMP)to mesophase microbeads was achieved by heating a mixture of NMP and fullerene(C_(60)).This is different from the conventional process of the liquid-phase carbonization of isotropic pitch to the emergence of carbon microbeads in the matrix and finally their growth to form a 100%anisotropic bulk meso-phase,but rather a reverse transformation.The effects of C_(60) loading and reaction temperature on the morphological transformation of mesophase were investigated by polarizing optical and scanning electron microscopies.The physical changes in the NMP induced by C_(60) were characterized by thermogravimetric analysis,Fourier transform infrared spectroscopy,X-ray diffractometry and Raman spectroscopy.The results show that the coalesced NMP can be converted to a spherical type at 300-320℃ with the addition of 5%C_(60),and the size of the mesophase microbeads increases with increasing temperature.Furthermore,a model is established to ex-plain the unique induction effect of C_(60) in the transformation process.This work makes the morphological transformation of MP con-trollable,and provides a new idea for the understanding and research of mesophase pitch.展开更多
Defect engineering by heteroatom doping gives carbon materials some new characteristics such as a different electronic structure and a high electrochemical activity,making them suitable for high-performance applicatio...Defect engineering by heteroatom doping gives carbon materials some new characteristics such as a different electronic structure and a high electrochemical activity,making them suitable for high-performance applications.N-doping has been widely investigated because of its similar atom radius to carbon,high electronegativity as well as many different configurations.We summarize the preparation methods and properties of N-doped carbon materials,and discuss their possible use in sodium ion storage.The relationships between N content/configuration and crystallinity,electronic conductivity,wettability,chemical reactivity as well as sodium ion storage performance are discussed.展开更多
The separation of aromatics from aliphatics is essential for achieving maximum exploitation of oil resources in the petrochemical industry.In this study,a series of metal chloride-based ionic liquids were prepared and...The separation of aromatics from aliphatics is essential for achieving maximum exploitation of oil resources in the petrochemical industry.In this study,a series of metal chloride-based ionic liquids were prepared and their performances in the separation of 1,2,3,4-tetrahydronaphthalene(tetralin)/dodecane and tetralin/decalin systems were studied.Among these ionic liquids,1-ethyl-3-methylimidazolium tetrachloroferrate([EMIM][FeCl_(4)])with the highest selectivity was used as the extractant.Density functional theory calculations showed that[EMIM][FeCl_(4)]interacted more strongly with tetralin than with dodecane and decalin.Energy decomposition analysis of[EMIM][FeCl_(4)]-tetralin indicated that electrostatics and dispersion played essential roles,and induction cannot be neglected.The van der Waals forces was a main effect in[EMIM][FeCl_(4)]-tetralin by independent gradient model analysis.The tetralin distribution coefficient and selectivity were 0.8 and 110,respectively,with 10%(mol)tetralin in the initial tetralin/dodecane system,and 0.67 and 19.5,respectively,with 10%(mol)tetralin in the initial tetralin/decalin system.The selectivity increased with decreasing alkyl chain length of the extractant.The influence of the extraction temperature,extractant dosage,and initial concentrations of the system components on the separation performance were studied.Recycling experiments showed that the regenerated[EMIM][FeCl_(4)]could be used repeatedly.展开更多
Silicon-based materials have demonstrated remarkable potential in high-energy-density batteries owing to their high theoretical capacity.However,the significant volume expansion of silicon seriously hinders its utiliz...Silicon-based materials have demonstrated remarkable potential in high-energy-density batteries owing to their high theoretical capacity.However,the significant volume expansion of silicon seriously hinders its utilization as a lithium-ion anode.Herein,a functionalized high-toughness polyimide(PDMI) is synthesized by copolymerizing the 4,4'-Oxydiphthalic anhydride(ODPA) with 4,4'-oxydianiline(ODA),2,3-diaminobenzoic acid(DABA),and 1,3-bis(3-aminopropyl)-tetramethyl disiloxane(DMS).The combination of rigid benzene rings and flexible oxygen groups(-O-) in the PDMI molecular chain via a rigidness/softness coupling mechanism contributes to high toughness.The plentiful polar carboxyl(-COOH) groups establish robust bonding strength.Rapid ionic transport is achieved by incorporating the flexible siloxane segment(Si-O-Si),which imparts high molecular chain motility and augments free volume holes to facilitate lithium-ion transport(9.8 × 10^(-10) cm^(2) s^(-1) vs.16 × 10^(-10) cm^(2) s~(-1)).As expected,the SiO_x@PDMI-1.5 electrode delivers brilliant long-term cycle performance with a remarkable capacity retention of 85% over 500 cycles at 1.3 A g^(-1).The well-designed functionalized polyimide also significantly enhances the electrochemical properties of Si nanoparticles electrode.Meanwhile,the assembled SiO_x@PDMI-1.5/NCM811 full cell delivers a high retention of 80% after 100 cycles.The perspective of the binder design strategy based on polyimide modification delivers a novel path toward high-capacity electrodes for high-energy-density batteries.展开更多
Intrinsic topological defect engineering has been proven as a promising strategy to elevate the electrocatalytic activity of carbon materials.However,the controllable construction of high-density and specific topologi...Intrinsic topological defect engineering has been proven as a promising strategy to elevate the electrocatalytic activity of carbon materials.However,the controllable construction of high-density and specific topological defects in carbon frameworks to reveal the relationship between reactivity and defect structure remains a challenging task.Herein,the intrinsic pentagon carbon sites that can favor electron overflow and enhance their binding affinity towards the intermediates of catalytic reaction are firstly presented by the work function and the p-band center calculations.To experimentally verify this,the cage-opening reaction of fullerene is proposed and utilized for synthesizing carbon quantum dots with specific pentagon configuration(CQDs-P),subsequently utilizing CQDs-P to modulate the micro-scale defect density of three-dimensional reduced graphene oxide(rGO)viaπ-πinteractions.The multiple spatial-scale rGO-conjugated CQDs-P structure simultaneously possesses abundant pentagon and edge defects as catalytic active sites and long-range-orderedπelectron delocalization system as conductive network.The defects-rich CQDs-P/rGO-4 all-carbon-based catalyst exhibits superb catalytic activity for triiodide reduction reaction with a high photoelectric conversion efficiency of 8.40%,superior to the Pt reference(7.97%).Theoretical calculations suggest that pentagon defects in the carbon frameworks can promote charge transfer and modulate the adsorption/dissociation behavior of the reaction intermediates,thus enhancing the electrocatalytic activity of the catalyst.This work confirms the role of intrinsic pentagon defects in catalytic reactions and provides a new insight into the synthesis of defects-rich carbon catalysts.展开更多
Nowadays,the rapid development of the social economy inevitably leads to global energy and environmental crisis.For this reason,more and more scholars focus on the development of photocatalysis and/or electrocatalysis...Nowadays,the rapid development of the social economy inevitably leads to global energy and environmental crisis.For this reason,more and more scholars focus on the development of photocatalysis and/or electrocatalysis technology for the advantage in the sustainable production of high-value-added products,and the high efficiency in pollutants remediation.Although there is plenty of outstanding research has been put forward continuously,most of them focuses on catalysis performance and reaction mechanisms in laboratory conditions.Realizing industrial application of photo/electrocatalytic processes is still a challenge that needs to be overcome by social demand.In this regard,this review comprehensively summarized several explorations in thefield of photo/electrocatalytic reduction towards potential industrial applications in recent years.Special attention is paid to the successful attempts and the current status of photo/electrocatalytic water splitting,carbon dioxide conversion,resource utilization from waste,etc.,by using advanced reactors.The key problems and challenges of photo/electrocatalysis in future industrial practice are also discussed,and the possible development directions are also pointed out from the industry view.展开更多
Coordination tuning electronic structure of host materials is a quite effective strategy for activating and improving the intrinsic properties.Herein,halogen anion(X-)-incorporated β-FeOOH(β-FeOOH(X),X=F-,Cl-,and Br...Coordination tuning electronic structure of host materials is a quite effective strategy for activating and improving the intrinsic properties.Herein,halogen anion(X-)-incorporated β-FeOOH(β-FeOOH(X),X=F-,Cl-,and Br-) was investigated with a spontaneous adsorption process,which realized a great improvement of supercapacitor performances by adjusting the coordination geometry.Experiments coupled with theoretical calculations demonstrated that the change of Fe-O bond length and structural distortion of β-FeOOH,which is rooted in halogen ions embedment,led to the relatively narrow band gap.Because of the strong electronegativity of X-,the Fe element in β-FeOOH(X)s presented the unexpected high valence state(3+δ),which is facilitating to adsorb S032-species.Consequently,the designed β-FeOOH(X)s exhibited the good electric conductivity and enhanced the contact between electrode and electrolyte.When used as a negative electrode,the β-FeOOH(F) showed the excellent specific capacity of 391.9 F g-1 at 1 A g-1 current density,almost tenfold improvement compared with initial β-FeOOH,with the superior rate capacity and cyclic stability.This combinational design principle of electronic structure and electrochemical performances provides a promising way to develop advanced electrode materials for supercapacitor.展开更多
A new type of rubidium ion-imprinted polymer has been synthesized by the surface-imprinting technique using methacrylic acid as the functional monomer,the rubidium ion as the template,methanol as the solvent,and silic...A new type of rubidium ion-imprinted polymer has been synthesized by the surface-imprinting technique using methacrylic acid as the functional monomer,the rubidium ion as the template,methanol as the solvent,and silica as a carrier.Ethylene glycol dimethacrylate and 2,2-azobisisobutyronitrile were used as acrosslinker and an initiator,respectively.In addition,based on the macrocyclic effect of crown ethers,the 18-crown-6 ligand was introduced as a ligand to fix the template ions better.Scanning electron microscopy,zeta-potential analysis,Fourier transform infrared spectroscopy,thermogravimetric analysis,and X-ray photoelectron spectroscopy were performed to characterize the ion-imprinted polymer.The effects of the preparation and adsorption conditions on the adsorption performance of the rubidium ion-imprinted polymer were investigated.The results indicated that the rubidium ion-imprinted polymer has high selectivity and faster kinetics than other adsorbents,with an equilibrium adsorption capacity of 200.19 mg·g^(-1)at 298 K within 25 min.The sorption isotherm was well described by the Freundlich isotherm model,while the adsorption kinetics fitted the pseudo-second-order kinetic model.Consecutive adsorption-desorption experiments showed that the ion-imprinted polymer had good chemical stability and reusability.展开更多
As the“emission peak and carbon neutrality peak”are proceeding all over the world,CO_(2) electroreduction is studied extensively as it is a powerful way to transform CO_(2)into value-added products.The earthabundant...As the“emission peak and carbon neutrality peak”are proceeding all over the world,CO_(2) electroreduction is studied extensively as it is a powerful way to transform CO_(2)into value-added products.The earthabundant Sn-based materials and copper sulfides as electrochemical catalysts have shown activity for generating formate from CO_(2) electroreduction.Herein,the composite of CuS and S-doped SnO_(2)(CuS/SnO_(2)-S)was synthesized by a redox reaction under room temperature.The unique structural reconstruction of CuS/SnO_(2)-S nanoparticles to Cu/Sn/Cu_(6.26)Sn_(5) nanowires decreases the energy barrier of the adsorption of CO_(2),and increases the adsorption of^(*)H,primarily suppressing the competing reaction of hydrogen evolution reaction(HER).As a result,at-0.8 V vs.RHE,it reaches an electrochemical CO_(2)-to-formate conversion with a Faradaic efficiency(FE)of 84.9%at a yield of 8860μmol h-1cm^(-2) under a partial current density of~18.8 mA cm^(-2) in an H-type reactor.This study provides significant insight into the structural evolution of the CuSn sulfides and the mechanism of formate formation.展开更多
Alumina(Al_(2)O_(3))is widely used in the chemical industry as the catalyst and support due to its high specific surface area,abundant pore size distribution and chemical stability.However,the occurrence of hydration ...Alumina(Al_(2)O_(3))is widely used in the chemical industry as the catalyst and support due to its high specific surface area,abundant pore size distribution and chemical stability.However,the occurrence of hydration in water environment,result in outstanding decrease in specific surface area and collapse of pore structure.In this work,dodecyl phosphoric acid(PA)is used to modify the surface of Al_(2)O_(3)to obtain a series of hydrophobic material(Al_(2)O_(3)-PA).Based on XPS and NMR analysis,PA is chemically bonded on Al_(2)O_(3)to form PAOAAl bond.Furthermore,BET and WCA results display that Al_(2)O_(3)-1PA exhibits excellent the hydrophobicity and hydrothermal stability while maintains the pore structure.Take it as the substrate to support the Pd nanoparticles,the as-prepared Pd/Al_(2)O_(3)-PA shows the superior catalytic performance in the hydrogenation of phenol and anthraquinone relative to Pd/Al_(2)O_(3),indicating the accessibility of Pd sites after PA modification.Especially,the significantly enhanced stability is also obtained in four cycles for aqueous phenol hydrogenation.This can be ascribed that the PA modification inhibits the aggregation of Pd nanoparticles and the products adhesion in the reaction process.The extension of PA coatings to monolithic catalysts could expand their current capabilities in industrial applications and warrants ongoing investigation.展开更多
Selective reductive amination of carbonyl compounds with high activity is very essential for the chemical and pharmaceutical industry,but scarcely successful paradigm was reported via efficient photocatalytic reaction...Selective reductive amination of carbonyl compounds with high activity is very essential for the chemical and pharmaceutical industry,but scarcely successful paradigm was reported via efficient photocatalytic reactions.Herein,the ultrasmall Ru nanoclusters(~0.9 nm)were successfully fabricated over P25 support with positive charged Ru^(δ+)species at the interface.A new route was developed to achieve the furfural(FAL)to furfurylamine(FAM)by coupling the light-driven reductive amination and hydrogen transfer of ethanol over this type catalyst.Strikingly,the photocatalytic activity and selectivity are strongly dependent on the particle size and electronic structure of Ruthenium.The Ru^(δ+)species at the interface promote the formation of active imine intermediates;moreover,the Ru nanoclusters facilitate the separation efficiency of electrons and holes as well as accelerate the further hydrogenation of imine intermediates to product primary amines.In contrast Ru particles in larger nanometer size facilitate the formation of the furfuryl alcohol and excessive hydrogenation products.In addition,the coupling byproducts can be effectively inhibited via the construction of sub-nanocluster.This study offers a new path to produce the primary amines from biomass-derived carbonyl compounds over hybrid semiconductor/metal-clusters photocatalyst via light-driven tandem catalytic process.展开更多
Catalytic oxidation of benzene with N_(2)O to phenol over the hierarchical and microporous Fe/ZSM-5-based catalysts in a continuous fixedbed reactor was investigated.The spent catalyst was in-situ regenerated by an ox...Catalytic oxidation of benzene with N_(2)O to phenol over the hierarchical and microporous Fe/ZSM-5-based catalysts in a continuous fixedbed reactor was investigated.The spent catalyst was in-situ regenerated by an oxidative treatment using N_(2)O and in total 10 reaction-regeneration cycles were performed.A 100% N_(2)O conversion,93.3% phenol selectivity,and high initial phenol formation rate of 16.49±0.06mmol_(phenol gcatalyst)^(-1)h^(-1)at time on stream(TOS) of 5 min,and a good phenol productivity of 147.06 mmol_(phenol gcatalyst)^(-1)during catalyst lifetime of 1800 min were obtained on a fresh hierarchical Fe/ZSM-5-Hi2.8 catalyst.With the reaction-regeneration cycle,N_(2)O conversion is fully recovered within TOS of 3 h,moreover,the phenol productivity was decreased ca.2.2±0.8% after each cycle,leading to a total phenol productivity of ca.0.44 ton_(pheol kg_(catalyst)^(-1)estimated for 300 cycles.Catalyst characterizations imply that the coke is rapidly deposited on catalyst surface in the initial TOS of 3 h(0.28 mgc_(gcatalyst)^(-1)min^(-1)) and gradually becomes graphitic during the TOS of 30 h with a slow formation rate of 0.06 mgc g_(catalyst)^(-1)min^(-1).Among others(e.g.,the decrease of textural property and acidity),the nearly complete coverage of the active Fe-O-Al sites by coke accounts for the main catalyst deactivation.Besides these reversible deactivation characteristics related to coking,the irreversible catalyst deactivation is also observed with the reaction-regeneration cycle.The latter is reflected by a further decreased amount of the active Fe-O-Al sites,which agglomerate on catalyst surface with the cycle,likely associated with the hard coke residue that is not completely removed by the regeneration.展开更多
This study presents a novel technique for the controllable preparation of photoluminescent substrates to enhance the photochemical microfluidic synthesis of vitamin D_3.The dip-coating method to prepare the substrates...This study presents a novel technique for the controllable preparation of photoluminescent substrates to enhance the photochemical microfluidic synthesis of vitamin D_3.The dip-coating method to prepare the substrates was experimentally optimized,and the corresponding emission behaviors were systematically investigated.The substrates were successfully used to enhance the ultraviolet B(UVB) emission of a low-power light source(e.g.,an 8 W lamp),whose UVB emission intensity was increased by approximately 11 times.By virtue of the novel light source,the productivity of a single set of photochemical microreactor with a 12-meter-long channel(0.6 mm i.d.) was increased to 1.83 kg·a^(-1),which was 42% higher than that of a 100 W lamp,and no cooling devices were used.The method is simple and has great potential to replace traditional medium-pressure mercury lamps for UVB-irradiated photochemical reactions.展开更多
基金financially supported by the National Natural Science Foundation of China(51872090,51772097,22304055)the Hebei Natural Science Fund for Distinguished Young Scholar(E2019209433)+4 种基金the Youth Talent Program of Hebei Provincial Education Department(BJ2018020)the Natural Science Foundation of Hebei Province(E2020209151,E2022209158,B2022209026,D2023209012)the Central Guiding Local Science and Technology Development Fund Project(236Z4409G)the Science and Technology Project of Hebei Education Department(SLRC2019028)the Science and Technology Planning Project of Tangshan City(22130227H)。
文摘With the increasing demand for scalable and cost-effective electrochemical energy storage,aqueous zinc ion batteries(AZIBs)have a broad application prospect as an inexpensive,efficient,and naturally secure energy storage device.However,the limitations suffered by AZIBs,including volume expansion and active materials dissolution of the cathode,electrochemical corrosion,irreversible side reactions,zinc dendrites of the anode,have seriously decelerated the civilianization process of AZIBs.Currently,polymers have tremendous superiority for application in AZIBs attributed to their exceptional chemical stability,tunable structure,high energy density and outstanding mechanical properties.Considering the expanding applications of AZIBs and the superiority of polymers,this comprehensive paper meticulously reviews the benefits of utilizing polymeric applied to cathodes and anodes,respectively.To begin with,with adjustable structure as an entry point,the correlation between polymer structure and the function of energy storage as well as optimization is deeply investigated in respect to the mechanism.Then,depending on the diversity of properties and structures,the development of polymers in AZIBs is summarized,including conductive polymers,redox polymers as well as carbon composite polymers for cathode and polyvinylidene fluoride-,carbonyl-,amino-,nitrile-based polymers for anode,and a comprehensive evaluation of the shortcomings of these strategies is provided.Finally,an outlook highlights some of the challenges posed by the application of polymers and offers insights into the potential future direction of polymers in AZIBs.It is designed to provide a thorough reference for researchers and developers working on polymer for AZIBs.
基金supported by the National Natural Science Foundationthe National Key Technologies R&D Program (2011BAE28B01)the 863 Program (2013AA032501)
文摘1 Introduction Magnesium salts are very important by-product of salt lake industry in West China.Nearly 200 million cubic meters of waste brine are released to the environment
基金financially supported by the National Key Research and Development Program of China (2018YFA0702002)the Beijing Natural Science Foundation (Z210016)the National Natural Science Foundation of China (21935001)。
文摘Single atomic catalysts(SACs),especially metal-nitrogen doped carbon(M-NC)catalysts,have been extensively explored for the electrochemical oxygen reduction reaction(ORR),owing to their high activity and atomic utilization efficiency.However,there is still a lack of systematic screening and optimization of local structures surrounding active centers of SACs for ORR as the local coordination has an essential impact on their electronic structures and catalytic performance.Herein,we systematic study the ORR catalytic performance of M-NC SACs with different central metals and environmental atoms in the first and second coordination sphere by using density functional theory(DFT)calculation and machine learning(ML).The geometric and electronic informed overpotential model(GEIOM)based on random forest algorithm showed the highest accuracy,and its R^(2) and root mean square errors(RMSE)were 0.96 and 0.21,respectively.30 potential high-performance catalysts were screened out by GEIOM,and the RMSE of the predicted result was only 0.12 V.This work not only helps us fast screen high-performance catalysts,but also provides a low-cost way to improve the accuracy of ML models.
基金supports from the National Natural Science Foundation of China(No.21776015)the University Scientific Research Project of Anhui Province(No.KJ2018A0065&KJ2020A0245).
文摘Adsorptive removal of heavy metal ions from wastewater is very important,and the key is the development of efficient sorbents.In this work,oxygenated alkynyl carbon materials(OACMs)were synthesized via mechanochemical reaction of CaC_(2) and a carbonate(CaCO_(3),Na2CO_(3),or NaHCO_(3))at ambient temperature.The resultant OACMs are micro mesoporous carbon nanomaterials with high specific area(>648 m2 g^(-1)),highly crosslinked texture,and rich alkynyl and oxygenated groups.The OACMs exhibit excellent Hg(Ⅱ)adsorption due to the soft acid-soft base interaction between alkynyl and Hg(Ⅱ),and OACM-3 derived from CaC_(2) and NaHCO_(3) has the saturated Hg(Ⅱ)adsorbance of 483.9 mg g^(-1)along with good selectivity and recyclability.The adsorption is mainly chemisorption following the Langmuir mode.OACM-3 also shows high adsorbance for other heavy metal ions,e.g.256.6 mg g^(-1)for Pb(II),232.4 mg g^(-1)for Zn(II),and 198.7 mg g^(-1)for Cu(II).This work expands the mechnochemical reaction of CaC_(2)with carbonates and possibly other oxyanionic salts,provides a new synthesis approach for functional alkynyl carbon materials with excellent adsorption performance for heavy metal ions,as well as a feasible approach for CO2 resource utilization.
基金This work was financially supported by the National Key Research and Development Program of China(2018YFA0702002)the Beijing Natural Science Foundation(Z210016)+1 种基金the National Natural Science Foundation of China(51967020,21935001)Shanxi Energy Internet Research Institute(SXEI 2023A004).
文摘The exploration of sustainable energy utilization requires the imple-mentation of advanced electrochemical devices for efficient energy conversion and storage,which are enabled by the usage of cost-effective,high-performance electro-catalysts.Currently,heterogeneous atomically dispersed catalysts are considered as potential candidates for a wide range of applications.Compared to conventional cata-lysts,atomically dispersed metal atoms in carbon-based catalysts have more unsatu-rated coordination sites,quantum size effect,and strong metal-support interactions,resulting in exceptional catalytic activity.Of these,dual-atomic catalysts(DACs)have attracted extensive attention due to the additional synergistic effect between two adja-cent metal atoms.DACs have the advantages of full active site exposure,high selectiv-ity,theoretical 100%atom utilization,and the ability to break the scaling relationship of adsorption free energy on active sites.In this review,we summarize recent research advancement of DACs,which includes(1)the comprehensive understanding of the synergy between atomic pairs;(2)the synthesis of DACs;(3)characterization meth-ods,especially aberration-corrected scanning transmission electron microscopy and synchrotron spectroscopy;and(4)electrochemical energy-related applications.The last part focuses on great potential for the electrochemical catalysis of energy-related small molecules,such as oxygen reduction reaction,CO_(2) reduction reaction,hydrogen evolution reaction,and N_(2) reduction reaction.The future research challenges and opportunities are also raised in prospective section.
基金supported by the National Natural Science Foundation of China (22125802 and 22108012)Natural Science Foundation of Beijing Municipality (2222017)Fundamental Research Funds for the Central Universities (BUCTRC-202109)。
文摘Latex wastewater is a kind of refractory organic wastewater containing high concentrations of organics and ammonia nitrogen.In this work,the combined process of forward osmosis(FO)and reverse osmosis(RO)was designed to treat the latex wastewater in the whole process,achieving the water recovery rate of 99%and basically no waste discharge after the catalytic oxidation process.The turbidity of the latex wastewater was decreased to below 1 NTU by microfiltration pretreatment,and then using MgCl_2 worked as the draw solution for FO process to treat the latex wastewater.Different operation conditions including adding acid or scale inhibitor as the pretreatment methods were conducted to improve the treatment performance of the combined process.After the treatment of the whole process,the concentration of COD was less than 20 mg·L^(-1),the concentration of NH_3-N was less than 10 mg·L^(-1),and the concentration of TP was less than 0.5 mg·L^(-1)for the treated latex wastewater.The water quality met standards of industrial water reuse after the complete analysis of the treated latex wastewater,meanwhile,useful substances of L-Quebrachitol(L-Q)were successfully extracted from the concentrated solution.Therefore,the combined process of FO and RO could realize the efficient treatment and reuse of latex wastewater,which provided with some important guidance on the industrial application.
基金Financial support from the National Key Research and Development Program of China(2022YFB3805602)the National Natural Science Foundation of China(22138001,22288102)the Fundamental Research Funds for the Central Universities。
文摘Glycerol carbonate,an important glycerol value-added product,has been widely used as an active intermediate and inert solvent in the synthesis of cosmetics,detergents,chemical intermediates,polymers,and so on.The direct carbonylation from glycerol with CO_(2)is considered a promising route,but still tough work due to the thermodynamic stability and the kinetic inertness of CO_(2).In this work,highlyselective direct carbonylation of glycerol and CO_(2)into glycerol carbonate has been achieved over highly dispersed MgInCe-mixed metal oxides(MgInCe-MMO),which were prepared through the topological transformation derived from the MgInCe-layered double hydroxides(MgInCe-LDHs).By precisely modulating the surface basic-acidic properties and the oxygen vacancies,an efficient carbonylation of glycerol with CO_(2)has been achieved with a selectivity of up to>99%to glycerol carbonate.Deep investigation into the synergistic catalysis of base-acid sites and oxygen vacancies has been clarified.
文摘A transformation of naphthalene-based coalescenced mesophase pitch(NMP)to mesophase microbeads was achieved by heating a mixture of NMP and fullerene(C_(60)).This is different from the conventional process of the liquid-phase carbonization of isotropic pitch to the emergence of carbon microbeads in the matrix and finally their growth to form a 100%anisotropic bulk meso-phase,but rather a reverse transformation.The effects of C_(60) loading and reaction temperature on the morphological transformation of mesophase were investigated by polarizing optical and scanning electron microscopies.The physical changes in the NMP induced by C_(60) were characterized by thermogravimetric analysis,Fourier transform infrared spectroscopy,X-ray diffractometry and Raman spectroscopy.The results show that the coalesced NMP can be converted to a spherical type at 300-320℃ with the addition of 5%C_(60),and the size of the mesophase microbeads increases with increasing temperature.Furthermore,a model is established to ex-plain the unique induction effect of C_(60) in the transformation process.This work makes the morphological transformation of MP con-trollable,and provides a new idea for the understanding and research of mesophase pitch.
文摘Defect engineering by heteroatom doping gives carbon materials some new characteristics such as a different electronic structure and a high electrochemical activity,making them suitable for high-performance applications.N-doping has been widely investigated because of its similar atom radius to carbon,high electronegativity as well as many different configurations.We summarize the preparation methods and properties of N-doped carbon materials,and discuss their possible use in sodium ion storage.The relationships between N content/configuration and crystallinity,electronic conductivity,wettability,chemical reactivity as well as sodium ion storage performance are discussed.
基金supported by the National Natural Science Foundation of China(22125802,22078010).
文摘The separation of aromatics from aliphatics is essential for achieving maximum exploitation of oil resources in the petrochemical industry.In this study,a series of metal chloride-based ionic liquids were prepared and their performances in the separation of 1,2,3,4-tetrahydronaphthalene(tetralin)/dodecane and tetralin/decalin systems were studied.Among these ionic liquids,1-ethyl-3-methylimidazolium tetrachloroferrate([EMIM][FeCl_(4)])with the highest selectivity was used as the extractant.Density functional theory calculations showed that[EMIM][FeCl_(4)]interacted more strongly with tetralin than with dodecane and decalin.Energy decomposition analysis of[EMIM][FeCl_(4)]-tetralin indicated that electrostatics and dispersion played essential roles,and induction cannot be neglected.The van der Waals forces was a main effect in[EMIM][FeCl_(4)]-tetralin by independent gradient model analysis.The tetralin distribution coefficient and selectivity were 0.8 and 110,respectively,with 10%(mol)tetralin in the initial tetralin/dodecane system,and 0.67 and 19.5,respectively,with 10%(mol)tetralin in the initial tetralin/decalin system.The selectivity increased with decreasing alkyl chain length of the extractant.The influence of the extraction temperature,extractant dosage,and initial concentrations of the system components on the separation performance were studied.Recycling experiments showed that the regenerated[EMIM][FeCl_(4)]could be used repeatedly.
基金supported by the National Natural Science Foundation of China (51673017)the National Natural Science Foundation of China (21404005)+1 种基金the Fundamental Research Funds for the Central Universities (XK1802-2)the Natural Science Foundation of Jiangsu Province (BK20150273)。
文摘Silicon-based materials have demonstrated remarkable potential in high-energy-density batteries owing to their high theoretical capacity.However,the significant volume expansion of silicon seriously hinders its utilization as a lithium-ion anode.Herein,a functionalized high-toughness polyimide(PDMI) is synthesized by copolymerizing the 4,4'-Oxydiphthalic anhydride(ODPA) with 4,4'-oxydianiline(ODA),2,3-diaminobenzoic acid(DABA),and 1,3-bis(3-aminopropyl)-tetramethyl disiloxane(DMS).The combination of rigid benzene rings and flexible oxygen groups(-O-) in the PDMI molecular chain via a rigidness/softness coupling mechanism contributes to high toughness.The plentiful polar carboxyl(-COOH) groups establish robust bonding strength.Rapid ionic transport is achieved by incorporating the flexible siloxane segment(Si-O-Si),which imparts high molecular chain motility and augments free volume holes to facilitate lithium-ion transport(9.8 × 10^(-10) cm^(2) s^(-1) vs.16 × 10^(-10) cm^(2) s~(-1)).As expected,the SiO_x@PDMI-1.5 electrode delivers brilliant long-term cycle performance with a remarkable capacity retention of 85% over 500 cycles at 1.3 A g^(-1).The well-designed functionalized polyimide also significantly enhances the electrochemical properties of Si nanoparticles electrode.Meanwhile,the assembled SiO_x@PDMI-1.5/NCM811 full cell delivers a high retention of 80% after 100 cycles.The perspective of the binder design strategy based on polyimide modification delivers a novel path toward high-capacity electrodes for high-energy-density batteries.
基金partly supported by the National Natural Science Foundation of China(22078052)the National Key R&D Program of China(2022YFB4101602)the Fundamental Research Funds for the Central Universities(DUT22LAB612)。
文摘Intrinsic topological defect engineering has been proven as a promising strategy to elevate the electrocatalytic activity of carbon materials.However,the controllable construction of high-density and specific topological defects in carbon frameworks to reveal the relationship between reactivity and defect structure remains a challenging task.Herein,the intrinsic pentagon carbon sites that can favor electron overflow and enhance their binding affinity towards the intermediates of catalytic reaction are firstly presented by the work function and the p-band center calculations.To experimentally verify this,the cage-opening reaction of fullerene is proposed and utilized for synthesizing carbon quantum dots with specific pentagon configuration(CQDs-P),subsequently utilizing CQDs-P to modulate the micro-scale defect density of three-dimensional reduced graphene oxide(rGO)viaπ-πinteractions.The multiple spatial-scale rGO-conjugated CQDs-P structure simultaneously possesses abundant pentagon and edge defects as catalytic active sites and long-range-orderedπelectron delocalization system as conductive network.The defects-rich CQDs-P/rGO-4 all-carbon-based catalyst exhibits superb catalytic activity for triiodide reduction reaction with a high photoelectric conversion efficiency of 8.40%,superior to the Pt reference(7.97%).Theoretical calculations suggest that pentagon defects in the carbon frameworks can promote charge transfer and modulate the adsorption/dissociation behavior of the reaction intermediates,thus enhancing the electrocatalytic activity of the catalyst.This work confirms the role of intrinsic pentagon defects in catalytic reactions and provides a new insight into the synthesis of defects-rich carbon catalysts.
基金supported by the National Natural Science Foundation of China(22278030,22090032,22090030,22288102,22242019)the Fundamental Research Funds for the Central Universities(buctrc202119,2312018RC07)+1 种基金Major Program of Qingyuan Innovation Laboratory(Grant No.001220005)the Experiments for Space Exploration Program and the Qian Xuesen Laboratory,China Academy of Space Technology。
文摘Nowadays,the rapid development of the social economy inevitably leads to global energy and environmental crisis.For this reason,more and more scholars focus on the development of photocatalysis and/or electrocatalysis technology for the advantage in the sustainable production of high-value-added products,and the high efficiency in pollutants remediation.Although there is plenty of outstanding research has been put forward continuously,most of them focuses on catalysis performance and reaction mechanisms in laboratory conditions.Realizing industrial application of photo/electrocatalytic processes is still a challenge that needs to be overcome by social demand.In this regard,this review comprehensively summarized several explorations in thefield of photo/electrocatalytic reduction towards potential industrial applications in recent years.Special attention is paid to the successful attempts and the current status of photo/electrocatalytic water splitting,carbon dioxide conversion,resource utilization from waste,etc.,by using advanced reactors.The key problems and challenges of photo/electrocatalysis in future industrial practice are also discussed,and the possible development directions are also pointed out from the industry view.
基金supported by the National Natural Science Foundation of China(Nos.2177060378,21627813,and 21521005)the Program for Changjiang Scholars,Innovative Research Teams in Universities(No.IRT1205)the Fundamental Research Funds for the Central Universities(Nos.12060093063 and XK1803-05).
文摘Coordination tuning electronic structure of host materials is a quite effective strategy for activating and improving the intrinsic properties.Herein,halogen anion(X-)-incorporated β-FeOOH(β-FeOOH(X),X=F-,Cl-,and Br-) was investigated with a spontaneous adsorption process,which realized a great improvement of supercapacitor performances by adjusting the coordination geometry.Experiments coupled with theoretical calculations demonstrated that the change of Fe-O bond length and structural distortion of β-FeOOH,which is rooted in halogen ions embedment,led to the relatively narrow band gap.Because of the strong electronegativity of X-,the Fe element in β-FeOOH(X)s presented the unexpected high valence state(3+δ),which is facilitating to adsorb S032-species.Consequently,the designed β-FeOOH(X)s exhibited the good electric conductivity and enhanced the contact between electrode and electrolyte.When used as a negative electrode,the β-FeOOH(F) showed the excellent specific capacity of 391.9 F g-1 at 1 A g-1 current density,almost tenfold improvement compared with initial β-FeOOH,with the superior rate capacity and cyclic stability.This combinational design principle of electronic structure and electrochemical performances provides a promising way to develop advanced electrode materials for supercapacitor.
基金supported by the National Natural Science Foundation of China(22125802 and 22078010)Beijing Natural Science Foundation(2222017)Big Science Project from BUCT(XK180301)。
文摘A new type of rubidium ion-imprinted polymer has been synthesized by the surface-imprinting technique using methacrylic acid as the functional monomer,the rubidium ion as the template,methanol as the solvent,and silica as a carrier.Ethylene glycol dimethacrylate and 2,2-azobisisobutyronitrile were used as acrosslinker and an initiator,respectively.In addition,based on the macrocyclic effect of crown ethers,the 18-crown-6 ligand was introduced as a ligand to fix the template ions better.Scanning electron microscopy,zeta-potential analysis,Fourier transform infrared spectroscopy,thermogravimetric analysis,and X-ray photoelectron spectroscopy were performed to characterize the ion-imprinted polymer.The effects of the preparation and adsorption conditions on the adsorption performance of the rubidium ion-imprinted polymer were investigated.The results indicated that the rubidium ion-imprinted polymer has high selectivity and faster kinetics than other adsorbents,with an equilibrium adsorption capacity of 200.19 mg·g^(-1)at 298 K within 25 min.The sorption isotherm was well described by the Freundlich isotherm model,while the adsorption kinetics fitted the pseudo-second-order kinetic model.Consecutive adsorption-desorption experiments showed that the ion-imprinted polymer had good chemical stability and reusability.
基金supported by the National Natural Science Foundation of China(Grant Nos.22278020,2177060378)the Program for Changjiang Scholars,Innovative Research Teams in Universities of China(Grant No.IRT1205)the Fundamental Research Funds for the Central Universities of China(Grant Nos.12060093063,XK1803-05)。
文摘As the“emission peak and carbon neutrality peak”are proceeding all over the world,CO_(2) electroreduction is studied extensively as it is a powerful way to transform CO_(2)into value-added products.The earthabundant Sn-based materials and copper sulfides as electrochemical catalysts have shown activity for generating formate from CO_(2) electroreduction.Herein,the composite of CuS and S-doped SnO_(2)(CuS/SnO_(2)-S)was synthesized by a redox reaction under room temperature.The unique structural reconstruction of CuS/SnO_(2)-S nanoparticles to Cu/Sn/Cu_(6.26)Sn_(5) nanowires decreases the energy barrier of the adsorption of CO_(2),and increases the adsorption of^(*)H,primarily suppressing the competing reaction of hydrogen evolution reaction(HER).As a result,at-0.8 V vs.RHE,it reaches an electrochemical CO_(2)-to-formate conversion with a Faradaic efficiency(FE)of 84.9%at a yield of 8860μmol h-1cm^(-2) under a partial current density of~18.8 mA cm^(-2) in an H-type reactor.This study provides significant insight into the structural evolution of the CuSn sulfides and the mechanism of formate formation.
基金supported by National Key Research&Development Program of China(2021YFB3801600)Fundamental Research Funds for the Central University(buctrc201921,JD2223,12060093063)Innovative Achievement Commercialization Service-Platform of Industrial Catalysis(2019-00900-2-1).
文摘Alumina(Al_(2)O_(3))is widely used in the chemical industry as the catalyst and support due to its high specific surface area,abundant pore size distribution and chemical stability.However,the occurrence of hydration in water environment,result in outstanding decrease in specific surface area and collapse of pore structure.In this work,dodecyl phosphoric acid(PA)is used to modify the surface of Al_(2)O_(3)to obtain a series of hydrophobic material(Al_(2)O_(3)-PA).Based on XPS and NMR analysis,PA is chemically bonded on Al_(2)O_(3)to form PAOAAl bond.Furthermore,BET and WCA results display that Al_(2)O_(3)-1PA exhibits excellent the hydrophobicity and hydrothermal stability while maintains the pore structure.Take it as the substrate to support the Pd nanoparticles,the as-prepared Pd/Al_(2)O_(3)-PA shows the superior catalytic performance in the hydrogenation of phenol and anthraquinone relative to Pd/Al_(2)O_(3),indicating the accessibility of Pd sites after PA modification.Especially,the significantly enhanced stability is also obtained in four cycles for aqueous phenol hydrogenation.This can be ascribed that the PA modification inhibits the aggregation of Pd nanoparticles and the products adhesion in the reaction process.The extension of PA coatings to monolithic catalysts could expand their current capabilities in industrial applications and warrants ongoing investigation.
基金financially supported by the National Natural Science Foundation of China(202102007,21978147 and 21935001)the Fundamental Research Funds for the Central Universities(buctrc202112)。
文摘Selective reductive amination of carbonyl compounds with high activity is very essential for the chemical and pharmaceutical industry,but scarcely successful paradigm was reported via efficient photocatalytic reactions.Herein,the ultrasmall Ru nanoclusters(~0.9 nm)were successfully fabricated over P25 support with positive charged Ru^(δ+)species at the interface.A new route was developed to achieve the furfural(FAL)to furfurylamine(FAM)by coupling the light-driven reductive amination and hydrogen transfer of ethanol over this type catalyst.Strikingly,the photocatalytic activity and selectivity are strongly dependent on the particle size and electronic structure of Ruthenium.The Ru^(δ+)species at the interface promote the formation of active imine intermediates;moreover,the Ru nanoclusters facilitate the separation efficiency of electrons and holes as well as accelerate the further hydrogenation of imine intermediates to product primary amines.In contrast Ru particles in larger nanometer size facilitate the formation of the furfuryl alcohol and excessive hydrogenation products.In addition,the coupling byproducts can be effectively inhibited via the construction of sub-nanocluster.This study offers a new path to produce the primary amines from biomass-derived carbonyl compounds over hybrid semiconductor/metal-clusters photocatalyst via light-driven tandem catalytic process.
基金Financial support by the Specialized Research Fund for Doctoral Program of Higher Education,China (No.20120010110003)。
文摘Catalytic oxidation of benzene with N_(2)O to phenol over the hierarchical and microporous Fe/ZSM-5-based catalysts in a continuous fixedbed reactor was investigated.The spent catalyst was in-situ regenerated by an oxidative treatment using N_(2)O and in total 10 reaction-regeneration cycles were performed.A 100% N_(2)O conversion,93.3% phenol selectivity,and high initial phenol formation rate of 16.49±0.06mmol_(phenol gcatalyst)^(-1)h^(-1)at time on stream(TOS) of 5 min,and a good phenol productivity of 147.06 mmol_(phenol gcatalyst)^(-1)during catalyst lifetime of 1800 min were obtained on a fresh hierarchical Fe/ZSM-5-Hi2.8 catalyst.With the reaction-regeneration cycle,N_(2)O conversion is fully recovered within TOS of 3 h,moreover,the phenol productivity was decreased ca.2.2±0.8% after each cycle,leading to a total phenol productivity of ca.0.44 ton_(pheol kg_(catalyst)^(-1)estimated for 300 cycles.Catalyst characterizations imply that the coke is rapidly deposited on catalyst surface in the initial TOS of 3 h(0.28 mgc_(gcatalyst)^(-1)min^(-1)) and gradually becomes graphitic during the TOS of 30 h with a slow formation rate of 0.06 mgc g_(catalyst)^(-1)min^(-1).Among others(e.g.,the decrease of textural property and acidity),the nearly complete coverage of the active Fe-O-Al sites by coke accounts for the main catalyst deactivation.Besides these reversible deactivation characteristics related to coking,the irreversible catalyst deactivation is also observed with the reaction-regeneration cycle.The latter is reflected by a further decreased amount of the active Fe-O-Al sites,which agglomerate on catalyst surface with the cycle,likely associated with the hard coke residue that is not completely removed by the regeneration.
基金the National Natural Science Foundation of China (21978008, 21606008)the State Key Laboratory of Chemical Engineering (SKL-ChE-17A02)the Fundamental Research Funds for the Central Universities (JD2017)。
文摘This study presents a novel technique for the controllable preparation of photoluminescent substrates to enhance the photochemical microfluidic synthesis of vitamin D_3.The dip-coating method to prepare the substrates was experimentally optimized,and the corresponding emission behaviors were systematically investigated.The substrates were successfully used to enhance the ultraviolet B(UVB) emission of a low-power light source(e.g.,an 8 W lamp),whose UVB emission intensity was increased by approximately 11 times.By virtue of the novel light source,the productivity of a single set of photochemical microreactor with a 12-meter-long channel(0.6 mm i.d.) was increased to 1.83 kg·a^(-1),which was 42% higher than that of a 100 W lamp,and no cooling devices were used.The method is simple and has great potential to replace traditional medium-pressure mercury lamps for UVB-irradiated photochemical reactions.