DFT study of VOC pollutants catalyzed by optimal Mo x O y : exploration of reaction mechanism of CH 3 R (R=CHO, CH 2 OH) + MoO 2

Ethanol (CH3CH2OH) and acetaldehyde (CH3CHO) are one of the most important volatile organic compounds (VOCs) found in the atmosphere and can be detected in diverse environments. But the mechanisms of catalytic reaction of ethanol and acetaldehyde have still not been fully understood. In the present paper, the mechanisms of the complicated catalytic reactions of transition metal oxide MoO2 with ethanol and acetaldehyde have been investigated theoretically. The geometries, energy values, and the lengths and angles of bond of all stationary points and transition states involved in the five different reaction pathways (Channels A1~A2 for CH3CHO, Channels B1~B3 for CH3CH2OH) are reported. We found that all reaction mechanisms are fully different from the mechanism of MoxOy catalyzing VOCs in previous studies. The results demonstrate that the activation energies of Channels A1(α) (1.45 kcal/mol) and B2(α) (1.56 kcal/mol) are the lowest. And the five reaction routes are addition reaction; this also means MoO2 tends to absorb ethanol and acetaldehyde pollution gas via addition reaction rather than releasing toxic substances. Besides, the results are compared with other catalysts and obtained that our barrier energy is the lowest. Obviously, molybdenum dioxide is the best catalyst to catalyze both ethanol and acetaldehyde. Therefore, the theoretical data obtained may provide a helpful tool for interpretation and prediction of the experimental findings about this reaction or similar ones. Besides, it is also a useful guide for understanding the chemical reactivity of MoO2 with alcohols and aldehydes, as well as the mechanism of other analogous reactions.