I do not recommend to you the correlation (regression) coefficient as indicative for reaction mechanism determination. I recommend to you a statistical evaluation: referred models can be grouped. As exampleP2, P3, P4, D1 and F0/R1 models can be expressed as,}

alpha^n=kt

or

ln(alpha)=ln(k)/n+ln(t)/n

which can be represented as: y=mx+b with y=ln(alpha), x=ln(t), m=1/n and b=ln(k)/n

You can perform linear regression and you must evaluate the 95% confidence interval for parameters. Therefore if your experimental results produces n=0.4(+-)0.2 you can conclude that your results gives evidence (with 95% of probability) that the mechanism is P2, P3 or P4 and definitively is not D1 or F0/R1. If your experiments produces n=0.5(+-)0.9, any of mechanisms P2, P3, P4, D1 or F0/R1 show significance evidence, you must test other mechanism. You can deduce similar analysis for the other mechanisms.

With respect to energy activation, the complete relation is k=k0exp(-E/RT). You have reason, the reaction catalyzed must have minor activation energy (E), however it is possible that catalyzed reaction has greater E but has greater k0 in a form that k catalyzed is grater that k no-catalyzed which is the expected effect in catalyzed reaction.

Dear Prof. Miguel Angel García-Alvarado

Thanks a million for your clear explanation. I would like to request you, if you can provide me few articles which reported greater E for catalyzed pyrolysis than for no-catalyzed pyrolysis

Excuse me. I am Chemical Reactor Engineering professor but I have not examples of reactions in which the activation energy (E) with catalysis are greater than without catalysis. However it is not impossible. One possible interpretation is that the catalyzed reaction requires more energy (with respect to non-catalyzed reaction) for activating the reaction but once that the energetic barrier is reached, the reaction constant is significantly greater than the non-catalyzed one.

The KAS and FWO isoconversional methods are not accurate for the processes with varying activation energies with conversion. You can read the papers from Prof. Vyazovkin.

The basic question is whether the weight was the same mass, samples without and with catalyst ??

best regards,

Andrzej

Dear Andrej Mianowski,

Yes, the mass of the sample is same (3 mg) for experiments run with and without catalyst

Dear Arun,

The obtained results indicate that the applied methodology is inadequate for studies of kinetics of the reaction, especially for determination of kinetic parameters.

Regards

A,

I would suggest to go for master-plots approach. Overlay the experimental master-plot data on the master-plots of the idealized kinetic models (the ones you provided in picture). From the overlay you will be able see to, which model is closest to your experimental data.

For details please read:

Article Impact of modified graphene and microwave irradiation on the...

Article Generalized Kinetic Master Plots for the Thermal Degradation...

As I guess, you have data in the form α = (mo-m)/mo vs T(t). You can use one of the methods listed above, which, in fact, come down to a different way of expressing the integral of non-elementary function. You can also directly integrate the mass balance equation dα/dt = k (T(t)) r (α), α(0)=0. You know T(t) and you can assume different forms of r(α). Any numerical method of integrating the ordinary differential equations is sufficient. It is up to you. - However, there will always be a problem with the interpretation of E or E(t) for a complex process Regards,