Poly(ethylene oxide)(PEO)-based polymer electrolytes show the prospect in all-solid-state lithium metal batteries;however,they present limitations of low room-temperature ionic conductivity,and interfacial incompatibi...Poly(ethylene oxide)(PEO)-based polymer electrolytes show the prospect in all-solid-state lithium metal batteries;however,they present limitations of low room-temperature ionic conductivity,and interfacial incompatibility with high voltage cathodes.Therefore,a salt engineering of 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonimide lithium salt(LiHFDF)/LiTFSI system was developed in PEO-based electrolyte,demonstrating to effectively regulate Li ion transport and improve the interfacial stability under high voltage.We show,by manipulating the interaction between PEO matrix and TFSI^(-)-HFDF^(-),the optimized solid-state polymer electrolyte achieves maximum Li+conduction of 1.24×10^(-4)S cm^(-1)at 40℃,which is almost 3 times of the baseline.Also,the optimized polymer electrolyte demonstrates outstanding stable cycling in the LiFePO_(4)/Li and LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)/Li(3.0-4.4 V,200 cycles)based all-solid-state lithium batteries at 40℃.展开更多
Electrochemical reduction of CO_(2)(CO_(2)RR)has become a research hot spot in recent years in the context of carbon neutrality.HCOOH is one of the most promising products obtained by electrochemical reduction of CO_(...Electrochemical reduction of CO_(2)(CO_(2)RR)has become a research hot spot in recent years in the context of carbon neutrality.HCOOH is one of the most promising products obtained by electrochemical reduction of CO_(2) due to its high energy value as estimated by market price per energy unit and wide application in chemical industry.Biomass is the most abundant renewable resource in the natural world.Coupling biomass oxidative conversion with CO_(2)RR driven by renewable electricity would well achieve carbon negativity.In this work,we comprehensively reviewed the current research progress on CO_(2)RR to produce HCOOH and coupled system for conversion of biomass and its derivatives to produce value-added products.Sn-and Bi-based electrocatalysts are discussed for CO_(2)RR with regards to the structure of the catalyst and reaction mechanisms.Electro-oxidation reactions of biomass derived sugars,alcohols,furan aldehydes and even polymeric components of lignocellulose were reviewed as alternatives to replace oxygen evolution reaction(OER)in the conventional electrolysis process.It was recommended that to further improve the efficiency of the coupled system,future work should be focused on the development of more efficient and stable catalysts,careful design of the electrolytic cells for improving the mass transfer and development of environment-friendly processes for recovering the formed formate and biomass oxidation products.展开更多
Plasma-based processes,particularly in carbon capture and utilization,hold great potential for addressing environmental challenges and advancing a circular carbon economy.While significant progress has been made in un...Plasma-based processes,particularly in carbon capture and utilization,hold great potential for addressing environmental challenges and advancing a circular carbon economy.While significant progress has been made in understanding plasma-induced reactions,plasma-catalyst interactions,and reactor development to enhance energy efficiency and conversion,there remains a notable gap in research concerning overall process development.This review emphasizes the critical need for considerations at the process level,including integration and intensification,to facilitate the industrialization of plasma technology for chemical production.Discussions centered on the development of plasma-based processes are made with a primary focus on CO_(2) conversion,offering insights to guide future work for the transition of the technology from laboratory scale to industrial applications.Identification of current research gaps,especially in upscaling and integrating plasma reactors with other process units,is the key to addressing critical issues.The review further delves into relevant research in process evaluation and assessment,providing methodological insights and highlighting key factors for comprehensive economic and sustainability analyses.Additionally,recent advancements in novel plasma systems are reviewed,presenting unique advantages and innovative concepts that could reshape the future of process development.This review provides essential information for navigating the path forward,ensuring a comprehensive understanding of challenges and opportunities in the development of plasma-based CCU process.展开更多
Anode materials for rechargeable electric car batteries are obtained from Li-metal owing to their extremely high specific capacity and low redox potential.Unfortunately,safety concerns related to dendrite formation on...Anode materials for rechargeable electric car batteries are obtained from Li-metal owing to their extremely high specific capacity and low redox potential.Unfortunately,safety concerns related to dendrite formation on the anode surface caused by the uneven distribution of Li-ions during the discharge process interfere with the use of Li-metal in industrial batteries.In this study,methyl vinyl sulfone(MVS),a sulfone-based functional electrolyte additive,is used in an additive engineering strategy to control Lielectrolyte interactions and address the aforementioned problems.Li dendrite growth may be restricted,and transition metal degradation on the surface of the cathode can be reduced by the MVS-derived functional electrolyte additive interfacial layer.The electrochemical performance of an ethylene carbonate/dimethyl carbonate(EC/DMC)+1 wt% MVS Li-metal anode of a Li||Li symmetric cell exhibits remarkable cycle stability,maintaining a low overvoltage for over 750 h at 1 mA cm^(-2),and capacity of 1 mA h cm^(-2).Additionally,LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811) full cells with the MVS additive exhibit enhanced electrochemical stability for 250 cycles at a current density of 100 mA g^(-1).This study provides an innovative approach for stabilizing the metal-electrolyte interfacial layer that may be used for practical applications in metal-based rechargeable batteries.展开更多
The concept of“carbon neutrality”poses a huge challenge for chemical engineering and brings great opportunities for boosting the development of novel technologies to realize carbon offsetting and reduce carbon emiss...The concept of“carbon neutrality”poses a huge challenge for chemical engineering and brings great opportunities for boosting the development of novel technologies to realize carbon offsetting and reduce carbon emissions.Developing high-efficient,low-cost,energy-efficient and eco-friendly microfluidicbased microchemical engineering is of great significance.Such kind of“green microfluidics”can reduce carbon emissions from the source of raw materials and facilitate controllable and intensified microchemical engineering processes,which represents the new power for the transformation and upgrading of chemical engineering industry.Here,a brief review of green microfluidics for achieving carbon neutral microchemical engineering is presented,with specific discussions about the characteristics and feasibility of applying green microfluidics in realizing carbon neutrality.Development of green microfluidic systems are categorized and reviewed,including the construction of microfluidic devices by bio-based substrate materials and by low carbon fabrication methods,and the use of more biocompatible and nondestructive fluidic systems such as aqueous two-phase systems(ATPSs).Moreover,low carbon applications benefit from green microfluidics are summarized,ranging from separation and purification of biomolecules,high-throughput screening of chemicals and drugs,rapid and cost-effective detections,to synthesis of fine chemicals and novel materials.Finally,challenges and perspectives for further advancing green microfluidics in microchemical engineering for carbon neutrality are proposed and discussed.展开更多
Small coin cell batteries are predominantly used for testing lithium-ion batteries(LIBs)in academia because they require small amounts of material and are easy to assemble.However,insufficient attention is given to di...Small coin cell batteries are predominantly used for testing lithium-ion batteries(LIBs)in academia because they require small amounts of material and are easy to assemble.However,insufficient attention is given to difference in cell performance that arises from the differences in format between coin cells used by academic researchers and pouch or cylindrical cells which are used in industry.In this article,we compare coin cells and pouch cells of different size with exactly the same electrode materials,electrolyte,and electrochemical conditions.We show the battery impedance changes substantially depending on the cell format using techniques including Electrochemical Impedance Spectroscopy(EIS)and Galvanostatic Intermittent Titration Technique(GITT).Using full cell NCA-graphite LIBs,we demonstrate that this difference in impedance has important knock-on effects on the battery rate performance due to ohmic polarization and the battery life time due to Li metal plating on the anode.We hope this work will help researchers getting a better idea of how small coin cell formats impact the cell performance and help predicting improvements that can be achieved by implementing larger cell formats.展开更多
Heavy-metal-free ternary Cu–In–Se quantum dots(CISe QDs)are promising for solar fuel production because of their low toxicity,tunable band gap,and high light absorption coefficient.Although defects significantly aff...Heavy-metal-free ternary Cu–In–Se quantum dots(CISe QDs)are promising for solar fuel production because of their low toxicity,tunable band gap,and high light absorption coefficient.Although defects significantly affect the photophysical properties of QDs,the influence on photoelectrochemical hydrogen production is not well understood.Herein,we present the defect engineering of CISe QDs for efficient solar-energy conversion.Lewis acid–base reactions between metal halide–oleylamine complexes and oleylammonium selenocarbamate are modulated to achieve CISe QDs with the controlled amount of Cu vacancies without changing their morphology.Among them,CISe QDs with In/Cu=1.55 show the most outstanding photoelectrochemical hydrogen generation with excellent photocurrent density of up to 10.7 mA cm-2(at 0.6 VRHE),attributed to the suitable electronic band structures and enhanced carrier concentrations/lifetimes of the QDs.The proposed method,which can effectively control the defects in heavy-metal-free ternary QDs,offers a deeper understanding of the effects of the defects and provides a practical approach to enhance photoelectrochemical hydrogen generation.展开更多
Pineapple fruit in the Republic of Guinea is currently less competitive in the West African sub-region due to the nutritional quality of the product.Thus,it is normal to review certain parameters such as:sensory,physi...Pineapple fruit in the Republic of Guinea is currently less competitive in the West African sub-region due to the nutritional quality of the product.Thus,it is normal to review certain parameters such as:sensory,physico-chemical in order to improve this classification.To do this,instead of buying samples on the market,the aim is to analyze fresh samples harvested in the production fields and send them to the laboratory for analysis of certain physico-chemical and microbiological parameters.Analytical results showed that the Brix content in fields I and II at Maferinyah(Forécariah)was higher(14.35 and 16.5)than that found in fields I and II at Friguiagbé(Kindia)(14.2 and 12.4),The pH of fruit from both localities varies between 3.48 and 3.56,with the highest acidity value found in Field I at Friguiagbé(Kindia)2.16 and the lowest value in Field II at Maferinyah(Forécariah)0.46.Moisture contents for both localities ranged from 82.56 to 89.5,with the highest value found at Field I in Maferinyah(Forécariah)89.5.Dry extract and ash in both localities would be in the range 10.54 to 17.45;0.33 to 1.43 respectively.The highest values for dry extract and ash were found in Fields I and II Friguiagbé(Kindia)17.45 and 1.43.The samples analyzed contained certain trace elements such as magnesium,sodium,iron and phosphorus.Microbiological analyses showed the presence of Escherichia coli(E.coli),yeast-molds,Staphylococcus aureus and the absence of salmonella.展开更多
In South Saharan countries, 85% of the population uses biomass as a primary energy source. Cameroon presents one of the highest biomass energy and sawmills produce important sawdust resources which are not used and ar...In South Saharan countries, 85% of the population uses biomass as a primary energy source. Cameroon presents one of the highest biomass energy and sawmills produce important sawdust resources which are not used and are burnt in piles leading to significant air toxic emissions. Therefore, we have to valorize industrially these available sawdusts. This study focuses on the physicochemical and thermochemical analysis of Ayous, Sapelli and Tali sawdust. The proximate and ultimate analysis, particle size, structural composition, as well as heavy metal content and calorific value were determined. In addition, the thermogravimetric mass losses were also estimated. The results showed that high water contents (24% - 41%) were recorded in the raw sawdust, and the thermal treatment reduced these contents from 78% to values in the range of 4% - 9%. The values for ash and volatile matter content were respectively between 0.25% - 0.74% and 68% - 76%. The LHV is higher in Ayous (17.5 MJ/kg) and Sapelli (16.8 MJ/kg) than that of Tali (15.7 MJ/kg). The concentration of heavy metals is very low in each species. Extractives are more present in Tali (16.06%) than in the other sawdusts. Pyrolysis of sawdust shows the typical decomposition of hemicellulose (270˚C - 325˚C), cellulose (325˚C - 400˚C) and lignin (200˚C - 550˚C) with a maximum loss of 75% at 370˚C and the melting point is 320˚C. The results of the sawdust parameters determined in the paper can be valorized to reduce pollutants emissions by developing the efficiency and effectiveness of biomass energy processes and promoting the use of biomass as a sustainable alternative to traditional fossil fuels.展开更多
Over the years, pineapple production in the Republic of Guinea has become less competitive in the West African sub-region, with a world ranking of 144th. It is therefore only natural to review certain parameters in or...Over the years, pineapple production in the Republic of Guinea has become less competitive in the West African sub-region, with a world ranking of 144th. It is therefore only natural to review certain parameters in order to improve this ranking. To do this, certain physico-chemical parameters of soil samples from Friguiagbé and Maferinyah (in the Kindia and Forécariah prefectures) were taken and analysed using the following techniques: Pipette de Robinson, Anne, Bray II, Kapen HICDVITZ, Mc. Lead (1982). The analytical results show that the soils at Friguiagbé in Kindia and Maferinyah in Forécariah are acidic, with pH values of 4.4 and 4.7 (fields I and II) and 4.8 and 4.7 (fields I and II) respectively. The soils have a silty-sandy texture. This study could therefore serve as a guide for the Ministry of Agriculture of the Republic of Guinea.展开更多
The chemical and mineralogical composition of bauxite deposits is a key factor in the profitability of refining processes. The study of bauxites from the Saföfö site has assessed variations in chemical and m...The chemical and mineralogical composition of bauxite deposits is a key factor in the profitability of refining processes. The study of bauxites from the Saföfö site has assessed variations in chemical and mineralogical composition under various conditions, as well as the optimum conditions for their exploitation. The methodologies used in this study include experimental methods for determining moisture content, chemical composition, mineralogical composition, and specific density of bauxite. The results show significant variation in moisture content among the bauxite samples, with values ranging from 2.90% to 17.80%. The silica percentages in the samples range from 1.69% to 8.14%, while alumina percentages vary from 36.81% to 54.03%. After calcination, alumina oxide percentages range from 40% to 75%. After chemical activation, alumina oxides Al2O3 range from 40% to over 50%. Gibbsite is the most abundant mineral, accounting for about 60% - 70% of the total composition of the bauxite samples. Samples A to F have bulk densities varying between approximately 3.6 and 3.9. Sample B has the highest density, around 3.9, while sample C has the lowest, at around 3.5. Bauxite mining at the Saföfö site offers significant potential for the alumina industry, provided appropriate processing methods are selected to maximize quality and profitability while minimizing environmental impact.展开更多
Multifunctional architecture with intriguing structural design is highly desired for realizing the promising performances in wearable sensors and flexible energy storage devices.Cellulose nanofiber(CNF)is employed for...Multifunctional architecture with intriguing structural design is highly desired for realizing the promising performances in wearable sensors and flexible energy storage devices.Cellulose nanofiber(CNF)is employed for assisting in building conductive,hyperelastic,and ultralight Ti_(3)C_(2)T_(x)MXene hybrid aerogels with oriented tracheid-like texture.The biomimetic hybrid aerogels are constructed by a facile bidirectional freezing strategy with CNF,carbon nanotube(CNT),and MXene based on synergistic electrostatic interaction and hydrogen bonding.Entangled CNF and CNT“mortars”bonded with MXene“bricks”of the tracheid structure produce good interfacial binding,and superior mechanical strength(up to 80%compressibility and extraordinary fatigue resistance of 1000 cycles at 50%strain).Benefiting from the biomimetic texture,CNF/CNT/MXene aerogel shows ultralow density of 7.48 mg cm^(-3)and excellent electrical conductivity(~2400 S m^(-1)).Used as pressure sensors,such aerogels exhibit appealing sensitivity performance with the linear sensitivity up to 817.3 kPa^(-1),which affords their application in monitoring body surface information and detecting human motion.Furthermore,the aerogels can also act as electrode materials of compressive solid-state supercapacitors that reveal satisfactory electrochemical performance(849.2 mF cm^(-2)at 0.8 mA cm^(-2))and superior long cycle compression performance(88%after 10,000 cycles at a compressive strain of 30%).展开更多
The concept of“green-ammonia-zero-carbon emission”is an emerging research topic in the global community and many countries driving toward decarbonizing a diversity of applications dependent on fossil fuels.In light ...The concept of“green-ammonia-zero-carbon emission”is an emerging research topic in the global community and many countries driving toward decarbonizing a diversity of applications dependent on fossil fuels.In light of this,electrochemical nitrogen reduction reaction(ENRR)received great attention at ambient conditions.The low efficiency(%)and ammonia(NH_(3))production rates are two major challenges in making a sustainable future.Besides,hydrogen evolution reaction is another crucial factor for realizing this NH_(3)synthesis to meet the large-scale commercial demand.Herein,the(i)importance of NH_(3)as an energy carrier for the next future,(ii)discussion with ENRR theory and the fundamental mechanism,(iii)device configuration and types of electrolytic systems for NH_(3)synthesis including key metrics,(iv)then moving into rising electrocatalysts for ENRR such as single-atom catalysts(SACs),MXenes,and metal–organic frameworks that were scientifically summarized,and(v)finally,the current technical contests and future perceptions are discussed.Hence,this review aims to give insightful direction and a fresh motivation toward ENRR and the development of advanced electrocatalysts in terms of cost,efficiency,and technologically large scale for the synthesis of green NH_(3).展开更多
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
Sodium iron hexacyanoferrate(FeHCF)is one of the most promising cathode materials for sodium-ion batteries(SIBs)due to its low cost theoretical capacity.However,the low electrochemical activity of Fe^(LS)(C)in FeHCF d...Sodium iron hexacyanoferrate(FeHCF)is one of the most promising cathode materials for sodium-ion batteries(SIBs)due to its low cost theoretical capacity.However,the low electrochemical activity of Fe^(LS)(C)in FeHCF drags down its practical capacity and potential plateau.Herein,FeHCF with high Fe^(LS)(C)electrochemical activity(C-FeHCF)is synthesized via a facile citric acid-assisted solvothermal method.As the cathode of SIBs,C-FeHCF shows superior cycling stability(ca.87.3%capacity retention for 1000 cycles at 10 C)and outstanding rate performance(ca.68.5%capacity retention at 50 C).Importantly,the contribution of Fe^(LS)(C)to the whole capacity was quantitatively analyzed via combining dQ/dV and discharge curve for the first time,and the index reaches 44.53%for C-FeHCF,close to the theoretical value.In-situ X-ray diffraction proves the structure stability of C-FeHCF during charge-discharge process,ensuring its superior cycling performance.Furthermore,the application feasibility of the C-FeHCF cathode in quasi-solid SIBs is also evaluated.The quasi-solid SIBs with the C-FeHCF cathode exhibit excellent electrochemical performance,delivering an initial discharge capacity of 106.5 mAh g^(−1) at 5 C and high capacity retention of 89.8%over 1200 cycles.This work opens new insights into the design and development of advanced cathode materials for SIBs and the beyond.展开更多
Transition metal phosphides(TMPs)have been regarded as alternative hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)catalysts owing to their comparable activity to those of noble metal-based catalysts...Transition metal phosphides(TMPs)have been regarded as alternative hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)catalysts owing to their comparable activity to those of noble metal-based catalysts.TMPs have been produced in various morphologies,including hollow and porous nanostructures,which are features deemed desirable for electrocatalytic materials.Templated synthesis routes are often responsible for such morphologies.This paper reviews the latest advances and existing challenges in the synthesis of TMP-based OER and HER catalysts through templated methods.A comprehensive review of the structure-property-performance of TMP-based HER and OER catalysts prepared using different templates is presented.The discussion proceeds according to application,first by HER and further divided among the types of templates used-from hard templates,sacrificial templates,and soft templates to the emerging dynamic hydrogen bubble template.OER catalysts are then reviewed and grouped according to their morphology.Finally,prospective research directions for the synthesis of hollow and porous TMP-based catalysts,such as improvements on both activity and stability of TMPs,design of environmentally benign templates and processes,and analysis of the reaction mechanism through advanced material characterization techniques and theoretical calculations,are suggested.展开更多
Rechargeable lithium-ion batteries(LIBs)afford a profound impact on our modern daily life.However,LIBs are approaching the theoretical energy density,due to the inherent limitations of intercalation chemistry;thus,the...Rechargeable lithium-ion batteries(LIBs)afford a profound impact on our modern daily life.However,LIBs are approaching the theoretical energy density,due to the inherent limitations of intercalation chemistry;thus,they cannot further satisfy the increasing demands of portable electronics,electric vehicles,and grids.Therefore,battery chemistries beyond LIBs are being widely investigated.Next-generation lithium(Li)batteries,which employ Li metal as the anode and intercalation or conversion materials as the cathode,receive the most intensive interest due to their high energy density and excellent potential for commercialization.Moreover,significant progress has been achieved in Li batteries attributed to the increasing fundamental understanding of the materials and reactions,as well as to technological improvement.This review starts by summarizing the electrolytes for next-generation Li batteries.Key challenges and recent progress in lithium-ion,lithium–sulfur,and lithium–oxygen batteries are then reviewed from the perspective of energy and chemical engineering science.Finally,possible directions for further development in Li batteries are presented.Next-generation Li batteries are expected to promote the sustainable development of human civilization.展开更多
Electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising candidate to achieve ammonia synthesis because of clean electric energy,moderate reaction condition,safe operating process and harmless by-...Electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising candidate to achieve ammonia synthesis because of clean electric energy,moderate reaction condition,safe operating process and harmless by-products.However,the chemical inertness of nitrogen and poor activated capacity on catalyst surface usually produce low ammonia yield and faradic efficiency.Herein,the microfluidic technology is proposed to efficiently fabricate enriched iridium nanodots/carbon architecture.Owing to in-situ co-precipitation reaction and microfluidic manipulation,the iridium nanodots/carbon nanomaterials possess small average size,uniform dispersion,high conductivity and abundant active sites,producing good proton activation and rapid electrons transmission and moderate adsorption/desorption capacity.As a result,the as-prepared iridium nanodots/carbon nanomaterials realize large ammonia yield of 28.73 μg h^(-1) cm^(-2) and faradic efficiency of 9.14%in KOH solution.Moreover,the high ammonia yield of 11.21 μg h^(-1) cm^(-2) and faradic efficiency of 24.30%are also achieved in H_(2)SO_(4) solution.The microfluidic method provides a reference for large-scale fabrication of nano-sized catalyst materials,which may accelerate the progress of electrocatalytic NRR in industrialization field.展开更多
Efficiently modulating the velocity distribution and flow pattern of non-Newtonian fluids is a critical challenge in the context of dual shaft eccentric mixers for process intensification,posing a significant barrier ...Efficiently modulating the velocity distribution and flow pattern of non-Newtonian fluids is a critical challenge in the context of dual shaft eccentric mixers for process intensification,posing a significant barrier for the existing technologies.Accordingly,this work reports a convenient strategy that changes the kinetic energy to controllably regulate the flow patterns from radial flow to axial flow.Results showed that the desired velocity distribution and flow patterns could be effectively obtained by varying the number and structure of baffles to change kinetic energy,and a more uniform velocity distribution,which could not be reached normally in standard baffle dual shaft mixers,was easily obtained.Furthermore,a comparative analysis of velocity and shear rate distributions is employed to elucidate the mechanism behind the generation of flow patterns in various dual-shaft eccentric mixers.Importantly,there is little difference in the power number of the laminar flow at the same Reynolds number,meaning that the baffle type has no effect on the power consumption,while the power number of both unbaffle and U-shaped baffle mixing systems decreases compared with the standard baffle mixing system in the transition flow.Finally,at the same rotational condition,the dimensionless mixing time of the U-shaped baffle mixing system is 15.3%and 7.9%shorter than that of the standard baffle and the unbaffle mixing system,respectively,which shows the advantage of the U-shaped baffle in stirring rate.展开更多
Helical hierarchy found in biomolecules like cellulose,chitin,and collagen underpins the remarkable mechanical strength and vibrant colors observed in living organisms.This study advances the integration of helical/ch...Helical hierarchy found in biomolecules like cellulose,chitin,and collagen underpins the remarkable mechanical strength and vibrant colors observed in living organisms.This study advances the integration of helical/chiral assembly and 3D printing technology,providing precise spatial control over chiral nano/microstructures of rod-shaped colloidal nanoparticles in intricate geometries.We designed reactive chiral inks based on cellulose nanocrystal(CNC)suspensions and acrylamide monomers,enabling the chiral assembly at nano/microscale,beyond the resolution seen in printed materials.We employed a range of complementary techniques including Orthogonal Superposition rheometry and in situ rheo-optic measurements under steady shear rate conditions.These techniques help us to understand the nature of the nonlinear flow behavior of the chiral inks,and directly probe the flow-induced microstructural dynamics and phase transitions at constant shear rates,as well as their post-flow relaxation.Furthermore,we analyzed the photo-curing process to identify key parameters affecting gelation kinetics and structural integrity of the printed object within the supporting bath.These insights into the interplay between the chiral inks self-assembly dynamics,3D printing flow kinematics and photopolymerization kinetics provide a roadmap to direct the out-of-equilibrium arrangement of CNC particles in the 3D printed filaments,ranging from uniform nematic to 3D concentric chiral structures with controlled pitch length,as well as random orientation of chiral domains.Our biomimetic approach can pave the way for the creation of materials with superior mechanical properties or programable photonic responses that arise from 3D nano/microstructure and can be translated into larger scale 3D printed designs.展开更多
基金supported by National Natural Science Foundation of China(Grant No.U1930113),ChinaNational Natural Science Foundation of China(52072036)
文摘Poly(ethylene oxide)(PEO)-based polymer electrolytes show the prospect in all-solid-state lithium metal batteries;however,they present limitations of low room-temperature ionic conductivity,and interfacial incompatibility with high voltage cathodes.Therefore,a salt engineering of 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonimide lithium salt(LiHFDF)/LiTFSI system was developed in PEO-based electrolyte,demonstrating to effectively regulate Li ion transport and improve the interfacial stability under high voltage.We show,by manipulating the interaction between PEO matrix and TFSI^(-)-HFDF^(-),the optimized solid-state polymer electrolyte achieves maximum Li+conduction of 1.24×10^(-4)S cm^(-1)at 40℃,which is almost 3 times of the baseline.Also,the optimized polymer electrolyte demonstrates outstanding stable cycling in the LiFePO_(4)/Li and LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)/Li(3.0-4.4 V,200 cycles)based all-solid-state lithium batteries at 40℃.
基金supported by the National Key R&D Program of China(2022YFA2105900)the National Natural Science Foundation of China(No.22178197)。
文摘Electrochemical reduction of CO_(2)(CO_(2)RR)has become a research hot spot in recent years in the context of carbon neutrality.HCOOH is one of the most promising products obtained by electrochemical reduction of CO_(2) due to its high energy value as estimated by market price per energy unit and wide application in chemical industry.Biomass is the most abundant renewable resource in the natural world.Coupling biomass oxidative conversion with CO_(2)RR driven by renewable electricity would well achieve carbon negativity.In this work,we comprehensively reviewed the current research progress on CO_(2)RR to produce HCOOH and coupled system for conversion of biomass and its derivatives to produce value-added products.Sn-and Bi-based electrocatalysts are discussed for CO_(2)RR with regards to the structure of the catalyst and reaction mechanisms.Electro-oxidation reactions of biomass derived sugars,alcohols,furan aldehydes and even polymeric components of lignocellulose were reviewed as alternatives to replace oxygen evolution reaction(OER)in the conventional electrolysis process.It was recommended that to further improve the efficiency of the coupled system,future work should be focused on the development of more efficient and stable catalysts,careful design of the electrolytic cells for improving the mass transfer and development of environment-friendly processes for recovering the formed formate and biomass oxidation products.
文摘Plasma-based processes,particularly in carbon capture and utilization,hold great potential for addressing environmental challenges and advancing a circular carbon economy.While significant progress has been made in understanding plasma-induced reactions,plasma-catalyst interactions,and reactor development to enhance energy efficiency and conversion,there remains a notable gap in research concerning overall process development.This review emphasizes the critical need for considerations at the process level,including integration and intensification,to facilitate the industrialization of plasma technology for chemical production.Discussions centered on the development of plasma-based processes are made with a primary focus on CO_(2) conversion,offering insights to guide future work for the transition of the technology from laboratory scale to industrial applications.Identification of current research gaps,especially in upscaling and integrating plasma reactors with other process units,is the key to addressing critical issues.The review further delves into relevant research in process evaluation and assessment,providing methodological insights and highlighting key factors for comprehensive economic and sustainability analyses.Additionally,recent advancements in novel plasma systems are reviewed,presenting unique advantages and innovative concepts that could reshape the future of process development.This review provides essential information for navigating the path forward,ensuring a comprehensive understanding of challenges and opportunities in the development of plasma-based CCU process.
基金supported by the Korea Institute for Advancement of Technology (KIAT) grant funded by the Korea Government (MOTIE) (P0017012, Human Resource Development Program for Industrial Innovation)the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (RS2024-00411892)。
文摘Anode materials for rechargeable electric car batteries are obtained from Li-metal owing to their extremely high specific capacity and low redox potential.Unfortunately,safety concerns related to dendrite formation on the anode surface caused by the uneven distribution of Li-ions during the discharge process interfere with the use of Li-metal in industrial batteries.In this study,methyl vinyl sulfone(MVS),a sulfone-based functional electrolyte additive,is used in an additive engineering strategy to control Lielectrolyte interactions and address the aforementioned problems.Li dendrite growth may be restricted,and transition metal degradation on the surface of the cathode can be reduced by the MVS-derived functional electrolyte additive interfacial layer.The electrochemical performance of an ethylene carbonate/dimethyl carbonate(EC/DMC)+1 wt% MVS Li-metal anode of a Li||Li symmetric cell exhibits remarkable cycle stability,maintaining a low overvoltage for over 750 h at 1 mA cm^(-2),and capacity of 1 mA h cm^(-2).Additionally,LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811) full cells with the MVS additive exhibit enhanced electrochemical stability for 250 cycles at a current density of 100 mA g^(-1).This study provides an innovative approach for stabilizing the metal-electrolyte interfacial layer that may be used for practical applications in metal-based rechargeable batteries.
基金the supports of the National Science Foundation of China (22008130, 22025801)the China Postdoctoral Science Foundation (2020M682124)+1 种基金the Qingdao Postdoctoral Researchers Applied Research Project Foundation (RZ2000001426)the Scientific Research Foundation for Youth Scholars from Qingdao University (DC1900014265) for this work
文摘The concept of“carbon neutrality”poses a huge challenge for chemical engineering and brings great opportunities for boosting the development of novel technologies to realize carbon offsetting and reduce carbon emissions.Developing high-efficient,low-cost,energy-efficient and eco-friendly microfluidicbased microchemical engineering is of great significance.Such kind of“green microfluidics”can reduce carbon emissions from the source of raw materials and facilitate controllable and intensified microchemical engineering processes,which represents the new power for the transformation and upgrading of chemical engineering industry.Here,a brief review of green microfluidics for achieving carbon neutral microchemical engineering is presented,with specific discussions about the characteristics and feasibility of applying green microfluidics in realizing carbon neutrality.Development of green microfluidic systems are categorized and reviewed,including the construction of microfluidic devices by bio-based substrate materials and by low carbon fabrication methods,and the use of more biocompatible and nondestructive fluidic systems such as aqueous two-phase systems(ATPSs).Moreover,low carbon applications benefit from green microfluidics are summarized,ranging from separation and purification of biomolecules,high-throughput screening of chemicals and drugs,rapid and cost-effective detections,to synthesis of fine chemicals and novel materials.Finally,challenges and perspectives for further advancing green microfluidics in microchemical engineering for carbon neutrality are proposed and discussed.
基金funding from the ERC(Consolidator Grant MIGHTY,866005)the Innovate UK(UKRI:104174)Faraday Institution-Future CAT(FIRG017)and Degradation(FIRG001)
文摘Small coin cell batteries are predominantly used for testing lithium-ion batteries(LIBs)in academia because they require small amounts of material and are easy to assemble.However,insufficient attention is given to difference in cell performance that arises from the differences in format between coin cells used by academic researchers and pouch or cylindrical cells which are used in industry.In this article,we compare coin cells and pouch cells of different size with exactly the same electrode materials,electrolyte,and electrochemical conditions.We show the battery impedance changes substantially depending on the cell format using techniques including Electrochemical Impedance Spectroscopy(EIS)and Galvanostatic Intermittent Titration Technique(GITT).Using full cell NCA-graphite LIBs,we demonstrate that this difference in impedance has important knock-on effects on the battery rate performance due to ohmic polarization and the battery life time due to Li metal plating on the anode.We hope this work will help researchers getting a better idea of how small coin cell formats impact the cell performance and help predicting improvements that can be achieved by implementing larger cell formats.
基金the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(grant nos.2021R1C1C1007844,2021M3I3A1085039,2020R1F1A1061505,and 2020R1C1C1012014).
文摘Heavy-metal-free ternary Cu–In–Se quantum dots(CISe QDs)are promising for solar fuel production because of their low toxicity,tunable band gap,and high light absorption coefficient.Although defects significantly affect the photophysical properties of QDs,the influence on photoelectrochemical hydrogen production is not well understood.Herein,we present the defect engineering of CISe QDs for efficient solar-energy conversion.Lewis acid–base reactions between metal halide–oleylamine complexes and oleylammonium selenocarbamate are modulated to achieve CISe QDs with the controlled amount of Cu vacancies without changing their morphology.Among them,CISe QDs with In/Cu=1.55 show the most outstanding photoelectrochemical hydrogen generation with excellent photocurrent density of up to 10.7 mA cm-2(at 0.6 VRHE),attributed to the suitable electronic band structures and enhanced carrier concentrations/lifetimes of the QDs.The proposed method,which can effectively control the defects in heavy-metal-free ternary QDs,offers a deeper understanding of the effects of the defects and provides a practical approach to enhance photoelectrochemical hydrogen generation.
文摘Pineapple fruit in the Republic of Guinea is currently less competitive in the West African sub-region due to the nutritional quality of the product.Thus,it is normal to review certain parameters such as:sensory,physico-chemical in order to improve this classification.To do this,instead of buying samples on the market,the aim is to analyze fresh samples harvested in the production fields and send them to the laboratory for analysis of certain physico-chemical and microbiological parameters.Analytical results showed that the Brix content in fields I and II at Maferinyah(Forécariah)was higher(14.35 and 16.5)than that found in fields I and II at Friguiagbé(Kindia)(14.2 and 12.4),The pH of fruit from both localities varies between 3.48 and 3.56,with the highest acidity value found in Field I at Friguiagbé(Kindia)2.16 and the lowest value in Field II at Maferinyah(Forécariah)0.46.Moisture contents for both localities ranged from 82.56 to 89.5,with the highest value found at Field I in Maferinyah(Forécariah)89.5.Dry extract and ash in both localities would be in the range 10.54 to 17.45;0.33 to 1.43 respectively.The highest values for dry extract and ash were found in Fields I and II Friguiagbé(Kindia)17.45 and 1.43.The samples analyzed contained certain trace elements such as magnesium,sodium,iron and phosphorus.Microbiological analyses showed the presence of Escherichia coli(E.coli),yeast-molds,Staphylococcus aureus and the absence of salmonella.
文摘In South Saharan countries, 85% of the population uses biomass as a primary energy source. Cameroon presents one of the highest biomass energy and sawmills produce important sawdust resources which are not used and are burnt in piles leading to significant air toxic emissions. Therefore, we have to valorize industrially these available sawdusts. This study focuses on the physicochemical and thermochemical analysis of Ayous, Sapelli and Tali sawdust. The proximate and ultimate analysis, particle size, structural composition, as well as heavy metal content and calorific value were determined. In addition, the thermogravimetric mass losses were also estimated. The results showed that high water contents (24% - 41%) were recorded in the raw sawdust, and the thermal treatment reduced these contents from 78% to values in the range of 4% - 9%. The values for ash and volatile matter content were respectively between 0.25% - 0.74% and 68% - 76%. The LHV is higher in Ayous (17.5 MJ/kg) and Sapelli (16.8 MJ/kg) than that of Tali (15.7 MJ/kg). The concentration of heavy metals is very low in each species. Extractives are more present in Tali (16.06%) than in the other sawdusts. Pyrolysis of sawdust shows the typical decomposition of hemicellulose (270˚C - 325˚C), cellulose (325˚C - 400˚C) and lignin (200˚C - 550˚C) with a maximum loss of 75% at 370˚C and the melting point is 320˚C. The results of the sawdust parameters determined in the paper can be valorized to reduce pollutants emissions by developing the efficiency and effectiveness of biomass energy processes and promoting the use of biomass as a sustainable alternative to traditional fossil fuels.
文摘Over the years, pineapple production in the Republic of Guinea has become less competitive in the West African sub-region, with a world ranking of 144th. It is therefore only natural to review certain parameters in order to improve this ranking. To do this, certain physico-chemical parameters of soil samples from Friguiagbé and Maferinyah (in the Kindia and Forécariah prefectures) were taken and analysed using the following techniques: Pipette de Robinson, Anne, Bray II, Kapen HICDVITZ, Mc. Lead (1982). The analytical results show that the soils at Friguiagbé in Kindia and Maferinyah in Forécariah are acidic, with pH values of 4.4 and 4.7 (fields I and II) and 4.8 and 4.7 (fields I and II) respectively. The soils have a silty-sandy texture. This study could therefore serve as a guide for the Ministry of Agriculture of the Republic of Guinea.
文摘The chemical and mineralogical composition of bauxite deposits is a key factor in the profitability of refining processes. The study of bauxites from the Saföfö site has assessed variations in chemical and mineralogical composition under various conditions, as well as the optimum conditions for their exploitation. The methodologies used in this study include experimental methods for determining moisture content, chemical composition, mineralogical composition, and specific density of bauxite. The results show significant variation in moisture content among the bauxite samples, with values ranging from 2.90% to 17.80%. The silica percentages in the samples range from 1.69% to 8.14%, while alumina percentages vary from 36.81% to 54.03%. After calcination, alumina oxide percentages range from 40% to 75%. After chemical activation, alumina oxides Al2O3 range from 40% to over 50%. Gibbsite is the most abundant mineral, accounting for about 60% - 70% of the total composition of the bauxite samples. Samples A to F have bulk densities varying between approximately 3.6 and 3.9. Sample B has the highest density, around 3.9, while sample C has the lowest, at around 3.5. Bauxite mining at the Saföfö site offers significant potential for the alumina industry, provided appropriate processing methods are selected to maximize quality and profitability while minimizing environmental impact.
基金supported by the Project of Jinan City(202228044)National Natural Science Foundation of China(32071720,32271814)+1 种基金the China Postdoctoral Science Foundation(2021M702456)China Scholarship Council for supporting their PhD program。
文摘Multifunctional architecture with intriguing structural design is highly desired for realizing the promising performances in wearable sensors and flexible energy storage devices.Cellulose nanofiber(CNF)is employed for assisting in building conductive,hyperelastic,and ultralight Ti_(3)C_(2)T_(x)MXene hybrid aerogels with oriented tracheid-like texture.The biomimetic hybrid aerogels are constructed by a facile bidirectional freezing strategy with CNF,carbon nanotube(CNT),and MXene based on synergistic electrostatic interaction and hydrogen bonding.Entangled CNF and CNT“mortars”bonded with MXene“bricks”of the tracheid structure produce good interfacial binding,and superior mechanical strength(up to 80%compressibility and extraordinary fatigue resistance of 1000 cycles at 50%strain).Benefiting from the biomimetic texture,CNF/CNT/MXene aerogel shows ultralow density of 7.48 mg cm^(-3)and excellent electrical conductivity(~2400 S m^(-1)).Used as pressure sensors,such aerogels exhibit appealing sensitivity performance with the linear sensitivity up to 817.3 kPa^(-1),which affords their application in monitoring body surface information and detecting human motion.Furthermore,the aerogels can also act as electrode materials of compressive solid-state supercapacitors that reveal satisfactory electrochemical performance(849.2 mF cm^(-2)at 0.8 mA cm^(-2))and superior long cycle compression performance(88%after 10,000 cycles at a compressive strain of 30%).
基金Ministry of Science and ICT,South Korea,Grant/Award Numbers:2019R1A2C2088174,2021R1A5A1084921。
文摘The concept of“green-ammonia-zero-carbon emission”is an emerging research topic in the global community and many countries driving toward decarbonizing a diversity of applications dependent on fossil fuels.In light of this,electrochemical nitrogen reduction reaction(ENRR)received great attention at ambient conditions.The low efficiency(%)and ammonia(NH_(3))production rates are two major challenges in making a sustainable future.Besides,hydrogen evolution reaction is another crucial factor for realizing this NH_(3)synthesis to meet the large-scale commercial demand.Herein,the(i)importance of NH_(3)as an energy carrier for the next future,(ii)discussion with ENRR theory and the fundamental mechanism,(iii)device configuration and types of electrolytic systems for NH_(3)synthesis including key metrics,(iv)then moving into rising electrocatalysts for ENRR such as single-atom catalysts(SACs),MXenes,and metal–organic frameworks that were scientifically summarized,and(v)finally,the current technical contests and future perceptions are discussed.Hence,this review aims to give insightful direction and a fresh motivation toward ENRR and the development of advanced electrocatalysts in terms of cost,efficiency,and technologically large scale for the synthesis of green NH_(3).
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supported by the Natural Science Foundation of Jiangsu Province (No.BK20210474)the National Natural Science Foundation of China (No.21938005)the Fundamental Research Funds for the Central Universities (No.JUSRP122013).
文摘Sodium iron hexacyanoferrate(FeHCF)is one of the most promising cathode materials for sodium-ion batteries(SIBs)due to its low cost theoretical capacity.However,the low electrochemical activity of Fe^(LS)(C)in FeHCF drags down its practical capacity and potential plateau.Herein,FeHCF with high Fe^(LS)(C)electrochemical activity(C-FeHCF)is synthesized via a facile citric acid-assisted solvothermal method.As the cathode of SIBs,C-FeHCF shows superior cycling stability(ca.87.3%capacity retention for 1000 cycles at 10 C)and outstanding rate performance(ca.68.5%capacity retention at 50 C).Importantly,the contribution of Fe^(LS)(C)to the whole capacity was quantitatively analyzed via combining dQ/dV and discharge curve for the first time,and the index reaches 44.53%for C-FeHCF,close to the theoretical value.In-situ X-ray diffraction proves the structure stability of C-FeHCF during charge-discharge process,ensuring its superior cycling performance.Furthermore,the application feasibility of the C-FeHCF cathode in quasi-solid SIBs is also evaluated.The quasi-solid SIBs with the C-FeHCF cathode exhibit excellent electrochemical performance,delivering an initial discharge capacity of 106.5 mAh g^(−1) at 5 C and high capacity retention of 89.8%over 1200 cycles.This work opens new insights into the design and development of advanced cathode materials for SIBs and the beyond.
基金the support from the CIPHER Project(IIID 2018-008)funded by the Commission on Higher Education-Philippine California Advanced Research Institutes(CHED-PCARI)。
文摘Transition metal phosphides(TMPs)have been regarded as alternative hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)catalysts owing to their comparable activity to those of noble metal-based catalysts.TMPs have been produced in various morphologies,including hollow and porous nanostructures,which are features deemed desirable for electrocatalytic materials.Templated synthesis routes are often responsible for such morphologies.This paper reviews the latest advances and existing challenges in the synthesis of TMP-based OER and HER catalysts through templated methods.A comprehensive review of the structure-property-performance of TMP-based HER and OER catalysts prepared using different templates is presented.The discussion proceeds according to application,first by HER and further divided among the types of templates used-from hard templates,sacrificial templates,and soft templates to the emerging dynamic hydrogen bubble template.OER catalysts are then reviewed and grouped according to their morphology.Finally,prospective research directions for the synthesis of hollow and porous TMP-based catalysts,such as improvements on both activity and stability of TMPs,design of environmentally benign templates and processes,and analysis of the reaction mechanism through advanced material characterization techniques and theoretical calculations,are suggested.
基金the National Key Research and Development Program(2016YFA0202500 and 2016YFA0200102)the National Natural Science Foundation of China(21676160,21776019,and 21825501)the Tsinghua University Initiative Scientific Research Program.
文摘Rechargeable lithium-ion batteries(LIBs)afford a profound impact on our modern daily life.However,LIBs are approaching the theoretical energy density,due to the inherent limitations of intercalation chemistry;thus,they cannot further satisfy the increasing demands of portable electronics,electric vehicles,and grids.Therefore,battery chemistries beyond LIBs are being widely investigated.Next-generation lithium(Li)batteries,which employ Li metal as the anode and intercalation or conversion materials as the cathode,receive the most intensive interest due to their high energy density and excellent potential for commercialization.Moreover,significant progress has been achieved in Li batteries attributed to the increasing fundamental understanding of the materials and reactions,as well as to technological improvement.This review starts by summarizing the electrolytes for next-generation Li batteries.Key challenges and recent progress in lithium-ion,lithium–sulfur,and lithium–oxygen batteries are then reviewed from the perspective of energy and chemical engineering science.Finally,possible directions for further development in Li batteries are presented.Next-generation Li batteries are expected to promote the sustainable development of human civilization.
基金supported by the National Natural Science Foundation of China(22025801)and(22208190)National Postdoctoral Program for Innovative Talents(BX2021146)Shuimu Tsinghua Scholar Program(2021SM055).
文摘Electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising candidate to achieve ammonia synthesis because of clean electric energy,moderate reaction condition,safe operating process and harmless by-products.However,the chemical inertness of nitrogen and poor activated capacity on catalyst surface usually produce low ammonia yield and faradic efficiency.Herein,the microfluidic technology is proposed to efficiently fabricate enriched iridium nanodots/carbon architecture.Owing to in-situ co-precipitation reaction and microfluidic manipulation,the iridium nanodots/carbon nanomaterials possess small average size,uniform dispersion,high conductivity and abundant active sites,producing good proton activation and rapid electrons transmission and moderate adsorption/desorption capacity.As a result,the as-prepared iridium nanodots/carbon nanomaterials realize large ammonia yield of 28.73 μg h^(-1) cm^(-2) and faradic efficiency of 9.14%in KOH solution.Moreover,the high ammonia yield of 11.21 μg h^(-1) cm^(-2) and faradic efficiency of 24.30%are also achieved in H_(2)SO_(4) solution.The microfluidic method provides a reference for large-scale fabrication of nano-sized catalyst materials,which may accelerate the progress of electrocatalytic NRR in industrialization field.
基金supported by the National Natural Science Foundation of China(22078030,52021004)Natural Science Foundation of Chongqing(2022NSCO-LZX0014)+1 种基金Fundamental Research Funds for the Central Universities(2022CDJQY-005,2023CDJXY-047)National Key Research and Development Project(2022YFC3901204)。
文摘Efficiently modulating the velocity distribution and flow pattern of non-Newtonian fluids is a critical challenge in the context of dual shaft eccentric mixers for process intensification,posing a significant barrier for the existing technologies.Accordingly,this work reports a convenient strategy that changes the kinetic energy to controllably regulate the flow patterns from radial flow to axial flow.Results showed that the desired velocity distribution and flow patterns could be effectively obtained by varying the number and structure of baffles to change kinetic energy,and a more uniform velocity distribution,which could not be reached normally in standard baffle dual shaft mixers,was easily obtained.Furthermore,a comparative analysis of velocity and shear rate distributions is employed to elucidate the mechanism behind the generation of flow patterns in various dual-shaft eccentric mixers.Importantly,there is little difference in the power number of the laminar flow at the same Reynolds number,meaning that the baffle type has no effect on the power consumption,while the power number of both unbaffle and U-shaped baffle mixing systems decreases compared with the standard baffle mixing system in the transition flow.Finally,at the same rotational condition,the dimensionless mixing time of the U-shaped baffle mixing system is 15.3%and 7.9%shorter than that of the standard baffle and the unbaffle mixing system,respectively,which shows the advantage of the U-shaped baffle in stirring rate.
基金the support from the University of South Carolina
文摘Helical hierarchy found in biomolecules like cellulose,chitin,and collagen underpins the remarkable mechanical strength and vibrant colors observed in living organisms.This study advances the integration of helical/chiral assembly and 3D printing technology,providing precise spatial control over chiral nano/microstructures of rod-shaped colloidal nanoparticles in intricate geometries.We designed reactive chiral inks based on cellulose nanocrystal(CNC)suspensions and acrylamide monomers,enabling the chiral assembly at nano/microscale,beyond the resolution seen in printed materials.We employed a range of complementary techniques including Orthogonal Superposition rheometry and in situ rheo-optic measurements under steady shear rate conditions.These techniques help us to understand the nature of the nonlinear flow behavior of the chiral inks,and directly probe the flow-induced microstructural dynamics and phase transitions at constant shear rates,as well as their post-flow relaxation.Furthermore,we analyzed the photo-curing process to identify key parameters affecting gelation kinetics and structural integrity of the printed object within the supporting bath.These insights into the interplay between the chiral inks self-assembly dynamics,3D printing flow kinematics and photopolymerization kinetics provide a roadmap to direct the out-of-equilibrium arrangement of CNC particles in the 3D printed filaments,ranging from uniform nematic to 3D concentric chiral structures with controlled pitch length,as well as random orientation of chiral domains.Our biomimetic approach can pave the way for the creation of materials with superior mechanical properties or programable photonic responses that arise from 3D nano/microstructure and can be translated into larger scale 3D printed designs.