ReaxFF molecular dynamics simulation of oxidation behavior of 3C-SiC in O2 and CO2

Abstract

This paper studies the oxidation behavior of nanoscale 3C-SiC in O2 and CO2 with a reactive force field molecular dynamics (ReaxFF MD) simulation. The first step of the oxidation of 3C-SiC involved five polar faces (C(100), Si(100), C(111), Si(111), m(11¯0)) in O2 which was simulated to explore the effect of polar faces on the oxidation process. It was observed that C-terminated face possesses a lower oxidative stability. The effect of oxygen concentration on the oxidation behavior of C(111) face was also checked. It seems that there exists little influence of variation of oxygen concentration on the activation energy of 3C-SiC. Then the oxidation process of C(111) face in CO2 was studied. The results reflected a much higher rate of activation energy of 3C-SiC in CO2 compared with that in O2. It can be inferred that the chemical reaction between 3C-SiC with CO2 was much slower than that in O2. Finally, the oxidation behavior of C(111) face in a mixed gas including O2, and CO2 was investigated while the effect of the ratio of concentration between O2 and CO2 on the oxidation behavior of 3C-SiC was further explored. The results indicate that there is no obvious coupling effect between CO2 and O2 during the process of chemical reaction.