Al-Decorated C(2)N Monolayer as a Potential Catalyst for NO Reduction with CO Molecules: A DFT Investigation

Developing efficient and economical catalysts for NO reduction is of great interest. Herein, the catalytic reduction of NO molecules on an Al-decorated C(2)N monolayer (Al-C(2)N) is systematically investigated using density functional theory (DFT) calculations. Our results reveal that the Al-C(2)N catalyst is highly selective for NO, more so than CO, according to the values of the adsorption energy and charge transfer. The NO reduction reaction more preferably undergoes the (NO)(2) dimer reduction process instead of the NO direct decomposition process. For the (NO)(2) dimer reduction process, two NO molecules initially co-adsorb to form (NO)(2) dimers, followed by decomposition into N(2)O and O(ads) species. On this basis, five kinds of (NO)(2) dimer structures that initiate four reaction paths are explored on the Al-C(2)N surface. Particularly, the cis-(NO)(2) dimer structures (D(cis-N) and D(cis-O)) are crucial intermediates for NO reduction, where the max energy barrier along the energetically most favorable pathway (path II) is as low as 3.6 kcal/mol. The remaining O(ads) species on Al-C(2)N are then easily reduced with CO molecules, being beneficial for a new catalytic cycle. These results, combined with its low-cost nature, render Al-C(2)N a promising catalyst for NO reduction under mild conditions.