Decomposition mechanism of ethanol molecule on the nano-boron surface: An experimental and DFT study

Abstract

The boron/ethanol nanofluid fuel with a high-energy density has better ignition performance as compared to traditional liquid fuels, so it has broad application prospects in fuel injection systems. However, the actual reaction mechanism of ethanol molecule over the nano-sized boron surface is still unclear and needs to be further explored. Hence, the specific reaction behavior of ethanol molecule on the boron (001) surface was investigated by a density functional theory (DFT) calculation. The geometric configuration and the energy of intermediates involved in the decomposition process of ethanol were analyzed and the dissociation route was drawn to find the optimal reaction path. The reaction CH3CH2OH → CH3CH2O → CH2CH2O → CHCH2O → CHCHO(Ⅰ) → CHCO → CH + CO → C + CO is the most preferable path. In this reaction path, the rate-determining step is the dehydrogenation of CH to form C. It is also found that oxygen is dissociated easily on the boron (001) surface and the presence of oxidation sites effectively decreases the energy barriers of the β-dehydrogenation of CH3CH2O and CHCHO (Ⅰ) species as well as the α-dehydrogenation of CHCH2O. This work emphasizes the important catalytic effect of boron on the decomposition of ethanol and can provide a benchmark for future research on the two-phase coupling reaction mechanism of emerging nanofluid fuels.