NO reduction over an Al-embedded MoS 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 NO and CO using Al-doped MoS (Al-MoS). According to our results, dissociation of NO molecules on Al-MoS 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) moieties is characterized as the first step of the NO reduction process. The formed (NO) is unstable on Al-MoS, and hence it is easily decomposed into NO molecules, and an oxygen atom is adsorbed onto the Al atom (O). This reaction step is exothermic and needs an activation energy of 0.37 eV to be overcome. Next, the O moiety is removed from the Al atom by a CO molecule, and thereby the Al-MoS catalyst is recovered for the next round of reaction. The side reaction producing NO the reaction of NO with the O moiety cannot proceed on Al-MoS due to its large activation energy.