A new method of the multiple rates isotemperature is proposed to define the most probable mechanismg(α) of thermal anlaysis; the iterative isoconversional procedure has been employed to estimate apparent activation e...A new method of the multiple rates isotemperature is proposed to define the most probable mechanismg(α) of thermal anlaysis; the iterative isoconversional procedure has been employed to estimate apparent activation energyE; the pre-exponential factorA is obtained on the basis ofE andg(α). By this new method, the thermal analysis kinetics triplet of dehydration of cobalt oxalate dihydrate is determined, apparent activation energyE is 99.84 kJ·mol?1; pre-exponential factorA is 3.427×109–3.872×109 s?1 and the most probable mechanism belongs to nucleation and growth,A m model, the range ofm is from 1.50 to 1.70. Key words multiple rates isotemperature method - isoconversional method - cobalt oxalate dihydrate - accomodation function - differential scanning calorimetry (DSC) CLC number O 636.1 Foundation item: Supported by the Key Foundation of the Science and Technology Committee of Hubei Province (2001ABA009)Biography: Li Li-qing (1977-), female, Master candidate, research direction: material synthesize and thermal analysis kinetics.展开更多
Well-defined two-dimensional(2D)cobalt oxalate(CoC_(2)O_(4)·2H_(2)O)nanosheets exhibit more excellent property than common bulk cobalt oxalate due to high specific surface areas and high-efficient transport of io...Well-defined two-dimensional(2D)cobalt oxalate(CoC_(2)O_(4)·2H_(2)O)nanosheets exhibit more excellent property than common bulk cobalt oxalate due to high specific surface areas and high-efficient transport of ion and electron.However,the delicate control of the 2D morphology of CoC_(2)O_(4)·2H_(2)O during their synthesis remains challenging.Herein,2D CoC_(2)O_(4)·2H_(2)O nanosheets(M1),grown by straightforward chemical precipitation,can be tuned from three-dimensional(3D)structure during their synthesis with no templates or capping agents.This control is obtained by rationally changing the ratio of reactants with ethylene glycol as solvent.Moreover,Co_(3)O_(4)/CoC_(2)O_(4)composites(M1-250)have been fabricated through low-temperature thermal treatment of the M1 precursor in air,which possess porous surfaces with the 2D morphology maintained.Benefiting from the porous surfaces,more redox-active sites and better electrical conductivity of Co_(3)O_(4),the constructed M1-250//AC aqueous device manifest improved kinetics of the electrochemistry process with energy density of 27.9 Wh/kg at 550.7 W/kg and good cycling stability with sustaining 73.0 m Ah/g after 5000 cycles.展开更多
文摘A new method of the multiple rates isotemperature is proposed to define the most probable mechanismg(α) of thermal anlaysis; the iterative isoconversional procedure has been employed to estimate apparent activation energyE; the pre-exponential factorA is obtained on the basis ofE andg(α). By this new method, the thermal analysis kinetics triplet of dehydration of cobalt oxalate dihydrate is determined, apparent activation energyE is 99.84 kJ·mol?1; pre-exponential factorA is 3.427×109–3.872×109 s?1 and the most probable mechanism belongs to nucleation and growth,A m model, the range ofm is from 1.50 to 1.70. Key words multiple rates isotemperature method - isoconversional method - cobalt oxalate dihydrate - accomodation function - differential scanning calorimetry (DSC) CLC number O 636.1 Foundation item: Supported by the Key Foundation of the Science and Technology Committee of Hubei Province (2001ABA009)Biography: Li Li-qing (1977-), female, Master candidate, research direction: material synthesize and thermal analysis kinetics.
基金the National Natural Science Foundation of China(No.U1904215)Natural Science Foundation of Jiangsu Province(No.BK20200044)Program for Young Changjiang Scholars of the Ministry of Education,China(No.Q2018270)。
文摘Well-defined two-dimensional(2D)cobalt oxalate(CoC_(2)O_(4)·2H_(2)O)nanosheets exhibit more excellent property than common bulk cobalt oxalate due to high specific surface areas and high-efficient transport of ion and electron.However,the delicate control of the 2D morphology of CoC_(2)O_(4)·2H_(2)O during their synthesis remains challenging.Herein,2D CoC_(2)O_(4)·2H_(2)O nanosheets(M1),grown by straightforward chemical precipitation,can be tuned from three-dimensional(3D)structure during their synthesis with no templates or capping agents.This control is obtained by rationally changing the ratio of reactants with ethylene glycol as solvent.Moreover,Co_(3)O_(4)/CoC_(2)O_(4)composites(M1-250)have been fabricated through low-temperature thermal treatment of the M1 precursor in air,which possess porous surfaces with the 2D morphology maintained.Benefiting from the porous surfaces,more redox-active sites and better electrical conductivity of Co_(3)O_(4),the constructed M1-250//AC aqueous device manifest improved kinetics of the electrochemistry process with energy density of 27.9 Wh/kg at 550.7 W/kg and good cycling stability with sustaining 73.0 m Ah/g after 5000 cycles.
