A novel micro kinetic analyzer(MFBK) for fluidized bed gas-solid reactions is developed.With this MFBK analyzer,the reaction rate and kinetic parameters can be deduced via measuring the time-dependent composition chan...A novel micro kinetic analyzer(MFBK) for fluidized bed gas-solid reactions is developed.With this MFBK analyzer,the reaction rate and kinetic parameters can be deduced via measuring the time-dependent composition changes of its evolved gas.By using a micro fluidized bed reactor,it is expected to enable the on-line feed of particle reactant based on a pulse solid conveying mechanics and the effective suppression of external gas diffusion in the reactor.This MFBK analyzer is evaluated through the decomposition of CaCO3 powder,giving an apparent activation energy of 142.73 kJ·mol-1 and a preexponential factor of 399777 s-1.This activation energy value is much lower then the TG-measured one of 184.3 kJ·mol-1 and within the literature-reported range of 120—280 kJ·mol-1.The measurement also provides a kinetic-model function with a correlation linearity of above 0.99.With this MFBK analyzer,the pyrolysis of coal and biomass at 800℃ is studied.The measured pyrolysis reaction finished in about 15 s,which is very close to the theoretically anticipation.This pyrolysis measurement with the MFBK analyzer can also identify a definite gas release order for typical gas species contained in the pyrolysis-formed gas products,which actually can provide a strong evidence for the deep insight in the pyrolysis reaction mechanism.展开更多
Transition metal nitride/carbide(TMN/C)have been actively explored as low-cost hydrogen evolution reaction(HER)electrocatalysts owing to their Pt-like physical and chemical properties.Unfortunately,pure TMN/C suffers ...Transition metal nitride/carbide(TMN/C)have been actively explored as low-cost hydrogen evolution reaction(HER)electrocatalysts owing to their Pt-like physical and chemical properties.Unfortunately,pure TMN/C suffers from strong hydrogen adsorption and lacks active centers for water dissociation.Herein,we developed a switchable WO_(3)-based in situ gas–solid reaction for preparing sophisticated Fe-N doped WC and Fe-C doped WN nanoarrays.Interestingly,the switch of codoping and phase can be effectively manipulated by regulating the amount of ferrocene.Resultant Fe-C-WN and Fe-N-WC exhibit robust electrocatalytic performance for HER in alkaline and acid electrolytes,respectively.The collective collaboration of morphological,phase and electronic effects are suggested to be responsible for the superior HER activity.The smallest|ΔGH*|value of Fe-NWC indicates preferable hydrogen-evolving kinetics on the Fe-N-WC surface for HER under acid condition,while Fe-C-WN is suggested to be beneficial to the adsorption and dissociation of H_(2)O for HER in alkaline electrolyte.展开更多
The present paper presents the structure, features and functions of a computerized system on kinetic analysis and evaluation of gas/solid reactions, KinPreGSR. Kin-PreGSR is a menu driven system, can be operated with ...The present paper presents the structure, features and functions of a computerized system on kinetic analysis and evaluation of gas/solid reactions, KinPreGSR. Kin-PreGSR is a menu driven system, can be operated with MS Windows as workbench in a PC computer. It has been developed using visual C++ with FoxPro hybrid coding technique.KinPreGSR combines the characteristics of gas/solid reactions with the kinetic models as well as mass and heat transfer equations. The database files were established for the apparent activation energies of some reduction and decomposition reactions to allow the prediction of the reaction kinetics to some extents. Outputs can be displayed using graphical or numerical forms. Examples regarding the oxide reduction and carbonate decomposition under isothermal conditions are given to show those functions.展开更多
The heterogeneous reaction of NO_(2)on NaCl particles has been investigated with the new sample preparation and the mode of gas-solid free diffusion.Diffuse Reflectance Infrared Fourier Transform Spectroscopy(DRIFTS)i...The heterogeneous reaction of NO_(2)on NaCl particles has been investigated with the new sample preparation and the mode of gas-solid free diffusion.Diffuse Reflectance Infrared Fourier Transform Spectroscopy(DRIFTS)is used to characterize the adsorbed products in situ,combined with Ion Chromatographic(IC),X-ray Photoelectron Spectroscopy(XPS)and Scan Electron Micros-copy(SEM).Our results indicate that the reaction is not limited to the surface of the NaCl particles,but penetrated into the upper layers.Surface reactive sites determine the reaction.Kinetic measurements show that nitrate formation on sodium chloride is second order in NO_(2)concentration and reactive uptake coefficient is(1.54±0.70)×10^(-5).展开更多
文摘A novel micro kinetic analyzer(MFBK) for fluidized bed gas-solid reactions is developed.With this MFBK analyzer,the reaction rate and kinetic parameters can be deduced via measuring the time-dependent composition changes of its evolved gas.By using a micro fluidized bed reactor,it is expected to enable the on-line feed of particle reactant based on a pulse solid conveying mechanics and the effective suppression of external gas diffusion in the reactor.This MFBK analyzer is evaluated through the decomposition of CaCO3 powder,giving an apparent activation energy of 142.73 kJ·mol-1 and a preexponential factor of 399777 s-1.This activation energy value is much lower then the TG-measured one of 184.3 kJ·mol-1 and within the literature-reported range of 120—280 kJ·mol-1.The measurement also provides a kinetic-model function with a correlation linearity of above 0.99.With this MFBK analyzer,the pyrolysis of coal and biomass at 800℃ is studied.The measured pyrolysis reaction finished in about 15 s,which is very close to the theoretically anticipation.This pyrolysis measurement with the MFBK analyzer can also identify a definite gas release order for typical gas species contained in the pyrolysis-formed gas products,which actually can provide a strong evidence for the deep insight in the pyrolysis reaction mechanism.
基金supported by Shandong Provincial Natural Science Foundation(No.ZR2019BB025)the National Natural Science Foundation of China(Nos.21976014 and U1930402)+1 种基金The Fundamental Research Funds for the Central Universities(FRFTP-20-11B and FRF-BR-20-02B)the generous computer time from TianHe2-JK Supercomputer Center。
文摘Transition metal nitride/carbide(TMN/C)have been actively explored as low-cost hydrogen evolution reaction(HER)electrocatalysts owing to their Pt-like physical and chemical properties.Unfortunately,pure TMN/C suffers from strong hydrogen adsorption and lacks active centers for water dissociation.Herein,we developed a switchable WO_(3)-based in situ gas–solid reaction for preparing sophisticated Fe-N doped WC and Fe-C doped WN nanoarrays.Interestingly,the switch of codoping and phase can be effectively manipulated by regulating the amount of ferrocene.Resultant Fe-C-WN and Fe-N-WC exhibit robust electrocatalytic performance for HER in alkaline and acid electrolytes,respectively.The collective collaboration of morphological,phase and electronic effects are suggested to be responsible for the superior HER activity.The smallest|ΔGH*|value of Fe-NWC indicates preferable hydrogen-evolving kinetics on the Fe-N-WC surface for HER under acid condition,while Fe-C-WN is suggested to be beneficial to the adsorption and dissociation of H_(2)O for HER in alkaline electrolyte.
基金supported by the National Natural Science Foundation of China(No.59774023).
文摘The present paper presents the structure, features and functions of a computerized system on kinetic analysis and evaluation of gas/solid reactions, KinPreGSR. Kin-PreGSR is a menu driven system, can be operated with MS Windows as workbench in a PC computer. It has been developed using visual C++ with FoxPro hybrid coding technique.KinPreGSR combines the characteristics of gas/solid reactions with the kinetic models as well as mass and heat transfer equations. The database files were established for the apparent activation energies of some reduction and decomposition reactions to allow the prediction of the reaction kinetics to some extents. Outputs can be displayed using graphical or numerical forms. Examples regarding the oxide reduction and carbonate decomposition under isothermal conditions are given to show those functions.
基金This work was supported by the National Basic Research Priorities Program(973)(Grant No.2002CB410802)the National Natural Science Foundation of China(Grant No.20077001)the Key Project of Ministry of Education of China.
文摘The heterogeneous reaction of NO_(2)on NaCl particles has been investigated with the new sample preparation and the mode of gas-solid free diffusion.Diffuse Reflectance Infrared Fourier Transform Spectroscopy(DRIFTS)is used to characterize the adsorbed products in situ,combined with Ion Chromatographic(IC),X-ray Photoelectron Spectroscopy(XPS)and Scan Electron Micros-copy(SEM).Our results indicate that the reaction is not limited to the surface of the NaCl particles,but penetrated into the upper layers.Surface reactive sites determine the reaction.Kinetic measurements show that nitrate formation on sodium chloride is second order in NO_(2)concentration and reactive uptake coefficient is(1.54±0.70)×10^(-5).
