A pore-array intensified tube-in-tube microchannel(PA-TMC),which is characterized by high throughput and low pressure drop,was developed as a gas–liquid contactor.The sulfite oxidation method was used to determine th...A pore-array intensified tube-in-tube microchannel(PA-TMC),which is characterized by high throughput and low pressure drop,was developed as a gas–liquid contactor.The sulfite oxidation method was used to determine the oxygen efficiency(φ)and volumetric mass transfer coefficient(k_(L)a)of PA-TMC,and the mass transfer amount per unit energy(ε)was calculated by using the pressure drop.The effects of structural and operating parameters were investigated systematically,and the twophase flow behavior was monitored by using a charge-coupled device imaging system.The results indicated that the gas absorption efficiency and mass transfer performance of the PA-TMC were improved with increasing pore number,flow rate,and number of helical coil turns and decreasing pore size,row number,annular size,annular length,and surface tension.Theφ,εand k La of PA-TMC could reach 31.3%,1.73×10^(-4) mol/J,and 7.0 s-1,respectively.The Sherwood number was correlated with the investigated parameters to guide the design of PA-TMC in gas absorption and mass transfer processes.展开更多
Catalysis has made great contributions to the productivity of human society. Therefore, the pursuit of new catalysts and research on catalytic processes has never stopped. Continuous and in-depth catalysis research si...Catalysis has made great contributions to the productivity of human society. Therefore, the pursuit of new catalysts and research on catalytic processes has never stopped. Continuous and in-depth catalysis research significantly increases the complexity of dynamic systems and multivariate optimization, thus posing higher challenges to research methodologies. Recently, the significant advancement of generative artificial intelligence (AI) provides new opportunities for catalysis research. Different from traditional discriminative AI, this state-of-the-art technique generates new samples based on existing data and accumulated knowledge, which endows it with attractive potential for catalysis research — a field featuring a vast exploration space, diverse data types and complex mapping relationships. Generative AI can greatly enhance both the efficiency and innovation capacity of catalysis research, subsequently fostering new scientific paradigms. This perspective covers the basic introduction, unique advantages of this powerful tool, and presents cases of generative AI implemented in various catalysis researches, including catalyst design and optimization, characterization technique enhancement and guidance for new research paradigms. These examples highlight its exceptional efficiency and general applicability. We further discuss the practical challenges in implementation and future development perspectives, ultimately aiming to promote better applications of generative AI in catalysis.展开更多
Aiming at inhibiting the irreversible P2–O2 phase transition of conventional P2-type cathode materials at high voltage and enhancing the cycling stability of sodium-ion batteries,in this article,based on a strategy o...Aiming at inhibiting the irreversible P2–O2 phase transition of conventional P2-type cathode materials at high voltage and enhancing the cycling stability of sodium-ion batteries,in this article,based on a strategy of adjusting the Na^(+)ion occupancy within the crystal structure,Na_(0.67)Ni_(0.33)Mn_(0.67–x)Fe_(x)O_(2)(NM–x Fe,x=0.10,0.15,0.20)cathode materials were synthesized by high shear mixer(HSM)-assisted co-precipitation method and evaluated the electrochemical performance at high voltage(4.35 V).The optimal sample NM–0.15Fe exhibits an initial discharge capacity of 130.8 mAh/g(0.1 C),with exceptional retention of 95.9%after 100 cycles(1 C).XRD analysis reveals that Fe intercalation promotes the more amount of Nae-similar occupation;the Nae/Naf ratio equals 1.93 for NM–0.15Fe versus 1.62 for NM,which enhances Na^(+)diffusion kinetics,as confirmed by GITT tests.Through characterizations of in situ XRD,XPS,HRTEM,CV,etc.,it is illustrated that the Fe^(3+)intercalation can effectively disrupt the Na^(+)/vacancy ordering and inhibit the harmful P2–O2 phase transition,and then improve the cycling stability of the cathode.DFT calculations disclose that intercalated Fe can reduce the electron densities of adjacent transition metallic elements,generating more repulsive forces impacted on sodium and consequently appearance of more Nae sites,leading to a lower Na^(+)diffusion energy barrier.Such strategy of modulating Na occupation sites in crystal structure is conducive to the development of low-cost and high-performance layered cathode materials for sodium-ion batteries.展开更多
The stability and activity of alkaline carbonate catalysts in supercritical water coal gasification has been investigated using density functional theory method. Our calculations present that the adsorption of Na2CO3 ...The stability and activity of alkaline carbonate catalysts in supercritical water coal gasification has been investigated using density functional theory method. Our calculations present that the adsorption of Na2CO3 on coal are more stable than that of K2CO3, but the stability of Na2CO3 is strongly reduced as the cluster gets larger. In supercritical water system, the dispersion and stability of Na2CO3 catalyst on coal support is strongly improved. During coal gasification process, Na2CO3 transforms with supercritical water into NaOH and NaHCO3, which is beneficial for hydrogen production. The transformation process has been studied via thermodynamics and kinetics ways. The selectively catalytic mechanism of NaOH and the intermediate form of sodium-based catalyst in water-gas shift reaction for higher hydrogen production has also been investigated. Furthermore, NaOH can transform back to Na2CO3 after catalyzing the water-gas shift reaction. Thus, the cooperative effects between supercritical water and Na2CO3 catalyst form a benignant circle which greatly enhances the reaction rate of coal gasification and promotes the production of hydrogen.展开更多
Lithium cobalt oxide(LiCoO_(2))is proverbially employed as cathode materials of lithium-ion batteries attributed to the high theoretical capacity,and currently,it is developing towards higher cut-off voltages in the p...Lithium cobalt oxide(LiCoO_(2))is proverbially employed as cathode materials of lithium-ion batteries attributed to the high theoretical capacity,and currently,it is developing towards higher cut-off voltages in the pursuit of higher energy density.However,it suffers from serious structural degradation and surface side reactions,in particular,at the voltage above 4.60 V,leading to rapid decay of the battery life.Taking into account the desirable oxygen buffering property and the fast ion mobility characteristic of cerium oxide fluoride,in this work,we prepared Ce&F co-modified LiCoO_(2)by using the precursors of Ce(NO_(3))_(3)·6H_(2)O and NH_(4)F,and evaluated the electrochemical performance under voltages exceeding 4.60 V.The results indicated that the modified samples have multiphase heterostructure of surface CeO_(2-x)and unique Ce-O-F solid solution phase.At 3.0–4.60 V and 25℃,the preferred sample LCO-0.5Ce-0.3F has a high initial discharge specific capacity of 221.9 mA h g^(-1)at 0.1 C,with the retention of 80.3%and 89.6%after 300 cycles at 1 and 5 C,comparing with the pristine LCO(56.4%and 22.6%).And at 3.0–4.65 V,its retention is 64.0%after 300 cycles at 1 C,versus 8.5%of the pristine LCO.Through structural characterizations and DFT calculations,it suggests that Ce^(4+)&F^(-)co-doping suppresses the H3 to H1/3 irreversible phase transition,stabilizes the lattice structure,and reduces the redox activity of the lattice oxygen by modulating the Co 3d–O 2p energy band,consequently improving the electrochemical performance of LiCoO_(2)at high voltages.展开更多
Copper has received extensive attention in the field of catalysis due to its rich natural reserves,low cost,and superior catalytic performance.Herein,we reviewed two modification mechanisms of co-catalyst on the coord...Copper has received extensive attention in the field of catalysis due to its rich natural reserves,low cost,and superior catalytic performance.Herein,we reviewed two modification mechanisms of co-catalyst on the coordination environment change of Cu-based catalysts:(1)change the electronic orbitals and geometric structure of Cu without any catalytic functions;(2)act as an additional active site with a certain catalytic function,as well as their catalytic mechanism in major reactions,including the hydrogenation to alcohols,dehydrogenation of alcohols,water gas shift reaction,reduction of nitrogenous compounds,electrocatalysis and others.The influencing mechanisms of different types of auxiliary metals on the structure-activity relationship of Cu-based catalysts in these reactions were especially summarized and discussed.The mechanistic understanding can provide significant guidance for the design and controllable synthesis of novel Cu-based catalysts used in many industrial reactions.展开更多
The reduced mechanism based on the minimized reaction network method can effectively solve the rigidity problem in the numerical calculation of turbulent internal combustion engine.The optimization of dynamic paramete...The reduced mechanism based on the minimized reaction network method can effectively solve the rigidity problem in the numerical calculation of turbulent internal combustion engine.The optimization of dynamic parameters of the reduced mechanism is the key to reproduce the experimental data.In this work,the experimental data of ignition delay times and laminar flame speeds were taken as the optimization objectives based on the machine-learning model constructed by radial basis function interpolation method,and pre-exponential factors and activation energies of H2 combustion mechanism were optimized.Compared with the origin mechanism,the performance of the optimized mechanism was significantly improved.The error of ignition delay times and laminar flame speeds was reduced by 24.3%and 26.8%,respectively,with 25%decrease in total mean error.The optimized mechanism was used to predict the ignition delay times,laminar flame speeds and species concentrations of jet stirred reactor,and the predicted results were in good agreement with experimental results.In addition,the differences of the key reactions of the combustion mechanism under specific working conditions were studied by sensitivity analysis.Therefore,the machine-learning model is a tool with broad application prospects to optimize various combustion mechanisms in a wide range of operating conditions.展开更多
As an advanced and new technology in molecular simulation fields, ReaxFF reactive force field has been developed and widely applied during the last two decades. ReaxFF bridges the gap between quantum chemistry （QC） ...As an advanced and new technology in molecular simulation fields, ReaxFF reactive force field has been developed and widely applied during the last two decades. ReaxFF bridges the gap between quantum chemistry （QC） and non-reactive empirical force field based molecular simulation methods, and aims to provide a transferable potential which can describe many chemical reactions with bond formation and breaking. This review presents an overview of the development and applications of ReaxFF reactive force field in the fields of reaction processes, biology and materials, including （1） the mechanism studies of organic reactions under extreme conditions （like high temperatures and pressures） related with high-energy materials, hydrocarbons and coals, （2） the structural properties ofnanomaterials such as graphene oxides, carbon nanotubes, silicon nanowires and metal nanoparticles, （3） interfacial interactions of solid-solid, solid-liquid and biological/inorganic surfaces, （4） the catalytic mechanisms of many types of metals and metal oxides, and （5） electrochemical mechanisms of fuel cells and lithium batteries. The limitations and challenges of ReaxFF reactive force field are also mentioned in this review, which will shed light on its future applications to a wider range of chemical environments.展开更多
Magnesium-related solid bases have long been considered catalysts with weak or medium basicity.Here we report the fabrication of Mg single-atom catalysts with superbasicity for the first time.A sublimation-migration-a...Magnesium-related solid bases have long been considered catalysts with weak or medium basicity.Here we report the fabrication of Mg single-atom catalysts with superbasicity for the first time.A sublimation-migration-anchoring strategy is employed,in which the Mg net is sublimated,transported by Ar,and trapped by defective graphene(producing Mg_(1)/G).Simulated and experimental results demonstrate that Mg single atoms are anchored on graphene in tetra-coordination,and Mg single atoms cooperating with C atoms give superbasicity,which differs from conventional alkali/alkaline earth metal oxides with basicity originating from O atoms.This new solid base is highly active in the synthesis of dimethyl carbonate through transesterification of ethylene carbonate with methanol,which is usually catalyzed by strong bases.The turnover frequency value reaches 99.6 h^(-1) on Mg_(1)/G,which is much higher than that of traditional Mg-related counterparts(1.0–5.6 h^(-1))and even superior to that of typical Na and K-related solid superbases(29.8–36.2 h^(-1))under similar conditions.展开更多
基金supported by National Key Research and Development Program(No.2016YFD0501402-04)National Natural Science Foundation of China(Nos.21776179,21621004)the Program for Changjiang Scholars and Innovative Research Team in University(No.IRT_15R46)。
文摘A pore-array intensified tube-in-tube microchannel(PA-TMC),which is characterized by high throughput and low pressure drop,was developed as a gas–liquid contactor.The sulfite oxidation method was used to determine the oxygen efficiency(φ)and volumetric mass transfer coefficient(k_(L)a)of PA-TMC,and the mass transfer amount per unit energy(ε)was calculated by using the pressure drop.The effects of structural and operating parameters were investigated systematically,and the twophase flow behavior was monitored by using a charge-coupled device imaging system.The results indicated that the gas absorption efficiency and mass transfer performance of the PA-TMC were improved with increasing pore number,flow rate,and number of helical coil turns and decreasing pore size,row number,annular size,annular length,and surface tension.Theφ,εand k La of PA-TMC could reach 31.3%,1.73×10^(-4) mol/J,and 7.0 s-1,respectively.The Sherwood number was correlated with the investigated parameters to guide the design of PA-TMC in gas absorption and mass transfer processes.
基金supported by the National Natural Science Foundation of China(T2441001)the National Key Research&Development Program of China(2023YFB4104503).
文摘Catalysis has made great contributions to the productivity of human society. Therefore, the pursuit of new catalysts and research on catalytic processes has never stopped. Continuous and in-depth catalysis research significantly increases the complexity of dynamic systems and multivariate optimization, thus posing higher challenges to research methodologies. Recently, the significant advancement of generative artificial intelligence (AI) provides new opportunities for catalysis research. Different from traditional discriminative AI, this state-of-the-art technique generates new samples based on existing data and accumulated knowledge, which endows it with attractive potential for catalysis research — a field featuring a vast exploration space, diverse data types and complex mapping relationships. Generative AI can greatly enhance both the efficiency and innovation capacity of catalysis research, subsequently fostering new scientific paradigms. This perspective covers the basic introduction, unique advantages of this powerful tool, and presents cases of generative AI implemented in various catalysis researches, including catalyst design and optimization, characterization technique enhancement and guidance for new research paradigms. These examples highlight its exceptional efficiency and general applicability. We further discuss the practical challenges in implementation and future development perspectives, ultimately aiming to promote better applications of generative AI in catalysis.
基金supported by Jing-Jin-Ji Regional Integrated Environmental Improvement,National Science and Technology Major Project(Nos.2024ZD1200303).
文摘Aiming at inhibiting the irreversible P2–O2 phase transition of conventional P2-type cathode materials at high voltage and enhancing the cycling stability of sodium-ion batteries,in this article,based on a strategy of adjusting the Na^(+)ion occupancy within the crystal structure,Na_(0.67)Ni_(0.33)Mn_(0.67–x)Fe_(x)O_(2)(NM–x Fe,x=0.10,0.15,0.20)cathode materials were synthesized by high shear mixer(HSM)-assisted co-precipitation method and evaluated the electrochemical performance at high voltage(4.35 V).The optimal sample NM–0.15Fe exhibits an initial discharge capacity of 130.8 mAh/g(0.1 C),with exceptional retention of 95.9%after 100 cycles(1 C).XRD analysis reveals that Fe intercalation promotes the more amount of Nae-similar occupation;the Nae/Naf ratio equals 1.93 for NM–0.15Fe versus 1.62 for NM,which enhances Na^(+)diffusion kinetics,as confirmed by GITT tests.Through characterizations of in situ XRD,XPS,HRTEM,CV,etc.,it is illustrated that the Fe^(3+)intercalation can effectively disrupt the Na^(+)/vacancy ordering and inhibit the harmful P2–O2 phase transition,and then improve the cycling stability of the cathode.DFT calculations disclose that intercalated Fe can reduce the electron densities of adjacent transition metallic elements,generating more repulsive forces impacted on sodium and consequently appearance of more Nae sites,leading to a lower Na^(+)diffusion energy barrier.Such strategy of modulating Na occupation sites in crystal structure is conducive to the development of low-cost and high-performance layered cathode materials for sodium-ion batteries.
基金supported by the National High-Tech Research and Development Program of China(2011AA05A201)the National Natural Science Foundation of China(21106094)Tianjin Science Foundation for Youths,China(12JCQNJC03100)
文摘The stability and activity of alkaline carbonate catalysts in supercritical water coal gasification has been investigated using density functional theory method. Our calculations present that the adsorption of Na2CO3 on coal are more stable than that of K2CO3, but the stability of Na2CO3 is strongly reduced as the cluster gets larger. In supercritical water system, the dispersion and stability of Na2CO3 catalyst on coal support is strongly improved. During coal gasification process, Na2CO3 transforms with supercritical water into NaOH and NaHCO3, which is beneficial for hydrogen production. The transformation process has been studied via thermodynamics and kinetics ways. The selectively catalytic mechanism of NaOH and the intermediate form of sodium-based catalyst in water-gas shift reaction for higher hydrogen production has also been investigated. Furthermore, NaOH can transform back to Na2CO3 after catalyzing the water-gas shift reaction. Thus, the cooperative effects between supercritical water and Na2CO3 catalyst form a benignant circle which greatly enhances the reaction rate of coal gasification and promotes the production of hydrogen.
基金partially supported by the Major Program of the National Natural Science Foundation of China(No.22090034)the Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘Lithium cobalt oxide(LiCoO_(2))is proverbially employed as cathode materials of lithium-ion batteries attributed to the high theoretical capacity,and currently,it is developing towards higher cut-off voltages in the pursuit of higher energy density.However,it suffers from serious structural degradation and surface side reactions,in particular,at the voltage above 4.60 V,leading to rapid decay of the battery life.Taking into account the desirable oxygen buffering property and the fast ion mobility characteristic of cerium oxide fluoride,in this work,we prepared Ce&F co-modified LiCoO_(2)by using the precursors of Ce(NO_(3))_(3)·6H_(2)O and NH_(4)F,and evaluated the electrochemical performance under voltages exceeding 4.60 V.The results indicated that the modified samples have multiphase heterostructure of surface CeO_(2-x)and unique Ce-O-F solid solution phase.At 3.0–4.60 V and 25℃,the preferred sample LCO-0.5Ce-0.3F has a high initial discharge specific capacity of 221.9 mA h g^(-1)at 0.1 C,with the retention of 80.3%and 89.6%after 300 cycles at 1 and 5 C,comparing with the pristine LCO(56.4%and 22.6%).And at 3.0–4.65 V,its retention is 64.0%after 300 cycles at 1 C,versus 8.5%of the pristine LCO.Through structural characterizations and DFT calculations,it suggests that Ce^(4+)&F^(-)co-doping suppresses the H3 to H1/3 irreversible phase transition,stabilizes the lattice structure,and reduces the redox activity of the lattice oxygen by modulating the Co 3d–O 2p energy band,consequently improving the electrochemical performance of LiCoO_(2)at high voltages.
基金This work was supported by the National Natural Science Foundation of China(Grant No.21576205)。
文摘Copper has received extensive attention in the field of catalysis due to its rich natural reserves,low cost,and superior catalytic performance.Herein,we reviewed two modification mechanisms of co-catalyst on the coordination environment change of Cu-based catalysts:(1)change the electronic orbitals and geometric structure of Cu without any catalytic functions;(2)act as an additional active site with a certain catalytic function,as well as their catalytic mechanism in major reactions,including the hydrogenation to alcohols,dehydrogenation of alcohols,water gas shift reaction,reduction of nitrogenous compounds,electrocatalysis and others.The influencing mechanisms of different types of auxiliary metals on the structure-activity relationship of Cu-based catalysts in these reactions were especially summarized and discussed.The mechanistic understanding can provide significant guidance for the design and controllable synthesis of novel Cu-based catalysts used in many industrial reactions.
基金National Natural Science Foundation of China(Grant No.U20A20151)National Key R&D Program of China(Grant No.2018YFA0702400).
文摘The reduced mechanism based on the minimized reaction network method can effectively solve the rigidity problem in the numerical calculation of turbulent internal combustion engine.The optimization of dynamic parameters of the reduced mechanism is the key to reproduce the experimental data.In this work,the experimental data of ignition delay times and laminar flame speeds were taken as the optimization objectives based on the machine-learning model constructed by radial basis function interpolation method,and pre-exponential factors and activation energies of H2 combustion mechanism were optimized.Compared with the origin mechanism,the performance of the optimized mechanism was significantly improved.The error of ignition delay times and laminar flame speeds was reduced by 24.3%and 26.8%,respectively,with 25%decrease in total mean error.The optimized mechanism was used to predict the ignition delay times,laminar flame speeds and species concentrations of jet stirred reactor,and the predicted results were in good agreement with experimental results.In addition,the differences of the key reactions of the combustion mechanism under specific working conditions were studied by sensitivity analysis.Therefore,the machine-learning model is a tool with broad application prospects to optimize various combustion mechanisms in a wide range of operating conditions.
文摘As an advanced and new technology in molecular simulation fields, ReaxFF reactive force field has been developed and widely applied during the last two decades. ReaxFF bridges the gap between quantum chemistry （QC） and non-reactive empirical force field based molecular simulation methods, and aims to provide a transferable potential which can describe many chemical reactions with bond formation and breaking. This review presents an overview of the development and applications of ReaxFF reactive force field in the fields of reaction processes, biology and materials, including （1） the mechanism studies of organic reactions under extreme conditions （like high temperatures and pressures） related with high-energy materials, hydrocarbons and coals, （2） the structural properties ofnanomaterials such as graphene oxides, carbon nanotubes, silicon nanowires and metal nanoparticles, （3） interfacial interactions of solid-solid, solid-liquid and biological/inorganic surfaces, （4） the catalytic mechanisms of many types of metals and metal oxides, and （5） electrochemical mechanisms of fuel cells and lithium batteries. The limitations and challenges of ReaxFF reactive force field are also mentioned in this review, which will shed light on its future applications to a wider range of chemical environments.
基金supported by the National Science Fund for Distinguished Young Scholars(22125804)the National Natural Science Foundation of China(22078155,21878149,U20A20151)the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Magnesium-related solid bases have long been considered catalysts with weak or medium basicity.Here we report the fabrication of Mg single-atom catalysts with superbasicity for the first time.A sublimation-migration-anchoring strategy is employed,in which the Mg net is sublimated,transported by Ar,and trapped by defective graphene(producing Mg_(1)/G).Simulated and experimental results demonstrate that Mg single atoms are anchored on graphene in tetra-coordination,and Mg single atoms cooperating with C atoms give superbasicity,which differs from conventional alkali/alkaline earth metal oxides with basicity originating from O atoms.This new solid base is highly active in the synthesis of dimethyl carbonate through transesterification of ethylene carbonate with methanol,which is usually catalyzed by strong bases.The turnover frequency value reaches 99.6 h^(-1) on Mg_(1)/G,which is much higher than that of traditional Mg-related counterparts(1.0–5.6 h^(-1))and even superior to that of typical Na and K-related solid superbases(29.8–36.2 h^(-1))under similar conditions.
