First-principles study of NO reduction by CO on transition metal atoms-doped CeO2(111)

We present here a density functional theory plus U study of NO reduction with CO, catalyzed by a single transition metal atom (TM1 = Zr1, Tc1, Ru1, Rh1, Pd1, Pt1)-doped CeO2(111). The catalytic center was identified as the TM dopant in combination with lattice oxygen. The investigation into N2 selectivity focused on three key elementary steps: gaseous N2O formation, subsequent re-adsorption, and N–O bond scission to produce N2. In these steps, Rh1, Pd1, and Pt1/CeO2(111) exhibit a higher selectivity, whereas the other systems (Zr1, Tc1, Ru1) TM1/CeO2 show a lower selectivity. The higher selectivity displayed by Pt1, Pd1, and Rh1 dopants arises from the availability of valence d electrons, which permit the formation of strong chemical bonds with the reactants and intermediates. Calculated results agree well with experimental findings, and the insights gained can be used to guide the rational design of the doped oxides for catalysis.

Graphical AbstractRight transition metal (TM)-doped CeO2(111) possesses high N2 selectivity because of the right-hand TMs being able to provide more d electrons for stronger binding between the TM and N-containing species. For the left-hand TMs, d electron availability is lower, leading to a weaker binding situation and lower N2 selectivity.Figure optionsDownload full-size imageDownload as PowerPoint slide