Fundamental understanding of the Di-Air system (an alternative NO abatement technology). I: The difference in reductant pre-treatment of ceria

A new dynamic N2O reduction system based on Rh/ceria–zirconia: from mechanistic insight towards a practical application

“…The formation of CO 2 started when the catalyst was largely oxidized, which suggested that CO 2 formed via a CO intermediate, which was subsequently oxidized into CO 2 by a ceria lattice oxygen. In previous studies, 18,19 we have demonstrated that CO could reduce oxidized ceria up to almost one hypothetical ceria layer under identical reaction conditions. Over H 2 reduced Rh/CLZ 15 N 2 O reduction proceeded for approximately 3400 pulses (Fig.…”

“…Characterization details of the CLZ support and Rh/CLZ catalyst were reported in detail elsewhere. [16][17][18][19][20][21] In brief, a 0.5 wt% Rh loading was confirmed by ICP-OES (0.0486 mmol g cat…”

“…A quasi-equilibrium between CO, CO 2 , Ce 3+ , and Ce 4+ appeared to limit the achievable oxidation degree of reduced ceria. 19 Therefore, it can be concluded that CO 2 was a mild oxidant as compared to NO and N 2 O, as it could hardly oxidize the deposited carbon. In the field of the dry CO 2 reforming of methane (DRM) reaction, the oxygen vacancies of a ceria support provided the catalytic sites for the CO 2 reduction to CO.…”

“…Details on the characterization and instruments can be found in our previous publications. [16][17][18][19][20][21] 2.2. Catalytic testing 2.2.1.…”

“…15 The comprehensive work by Wang and Makkee has addressed the working principle and application of this Di-Air system in NO reduction. [16][17][18][19][20][21] Oxygen vacancies within the ceria lattice of a reduced ceria, Pt/ceria or Rh/ceria were found to be the selective catalytic sites for the NO reduction into only N 2 (100% selectivity). 16 Even at low NO concentrations (ppm levels), NO could compete for oxygen vacancies with (100×) excess of O 2 and CO 2 .…”