Nitric oxide reduction by carbon monoxide and carbon monoxide oxidation by O2 over Co–Mn composite oxide material

Low Temperature NO and CO Conversion with a Mechanistic Approach on Ru-Composed Cerium Oxide

Catalytic reduction of NO with CO at a lower temperature is an extremely challenging task, thus requiring conceivable surfaces to overcome such issues. Ru-substituted CeO2 catalysts prepared via the solution combustion method were employed in CO oxidation and NO-CO conversion studies. The characterization for material formation and surface structure was carried out through XRD, SEM, TEM, and BET surface area. The catalytic study revealed the promising behavior of 5% Ru in CeO2 for the 100% conversion of NO-CO at 150 °C, proving it to be an excellent exhaust material. These observed results are also supported by temperature-programmed studies, i.e. TPD of NO and CO in addition to NH3-TPD and H2-TPR for their convincible surface interaction that is inclined toward a significant change in the conversion path. Additionally, the proposed mechanism, based on the experimental evidence, sheds light on the NO-CO redox reaction, directing the reaction pathway toward the Langmuir-Hinshelwood and Mars-Van Krevelen-type route. Moreover, the exceptional performance can be attributed to the strategic incorporation of Ru in CeO2, where the strong interaction of Ru-Ce is able to gain a high synergy for NO and CO conversion.

Acid-Base Surface-Driven NO-CO Conversion over Copper-Manganese-Based Metal Oxides

Recently, tuning catalytic material has gained huge importance for enhancing the catalytic performance of reactions. The present work describes the influence of aluminum in copper-manganese composite oxide with respect to the NO-CO redox reaction. The Al³⁺ fabricated composite oxide showed the highest conversion in a lower temperature window. The nanocomposite metal oxide of Cu-Mn formed as a porous structure with aluminum and helped in establishing a more surface acidic/basic character on the catalyst. These acidic/basic sites are crucial in activating the NO and CO chemisorption for significant redox conversion.