NO reduction over an Al-embedded MoS 2 monolayer: a first-principles study.

Converting toxic air pollutants such as nitric oxide (NO) and carbon monoxide (CO) into less harmful gases remains a critical challenge for many industrial technologies. Here, by performing first-principles calculations, we introduce a cheap, stable and novel catalyst for the conversion of NO and CO molecules into N 2 O and CO 2 using Al-doped MoS 2 (Al-MoS 2 ). According to our results, dissociation of NO molecules on Al-MoS 2 has a large energy barrier (3.62 eV), suggesting that it is impossible at ambient temperature. In contrast, the coadsorption of NO molecules to form (NO) 2 moieties is characterized as the first step of the NO reduction process. The formed (NO) 2 is unstable on Al-MoS 2 , and hence it is easily decomposed into N 2 O molecules, and an oxygen atom is adsorbed onto the Al atom (O ads ). This reaction step is exothermic and needs an activation energy of 0.37 eV to be overcome. Next, the O ads moiety is removed from the Al atom by a CO molecule, and thereby the Al-MoS 2 catalyst is recovered for the next round of reaction. The side reaction producing NO 2 via the reaction of NO with the O ads moiety cannot proceed on Al-MoS 2 due to its large activation energy.