Kinetic study of photodegradation of methylene blue over P25-graphene and P25-CNT nanocomposites using Monte Carlo simulation

Abstract

Kinetic Monte Carlo simulation was applied to investigation of kinetics and photodecomposition mechanism of methylene blue over P25, P25-graphene, and P25-CNT nanocomposite catalyst under UV and visible irradiations. The reaction kinetic mechanisms of each abovementioned catalytic systems has been attained. The rate constants values for the each step of the reaction mechanisms (including recombination and charge transfer) were obtained as adjustable parameters by kinetic Monte Carlo simulation. The high value of the rate constant for electron transfer to graphene and CNT exhibits this transmission is occurred fast. The photoinduced electrons and holes can recombine with rate constant value about 0.001 min^–1, but the rate constant of electron transfer is much higher than recombination. It was shown the rate constant of electron transfer to graphene is equal to CNT. There is a small difference between photocatalytic activity of P25-Gr and P25-CNT. The kinetic Monte Carlo simulation results of this research have satisfactorily agreement with the available experimental data for the methylene blue photodegradation.