Study of Na/Cu/TiO2 catalysts for the storage and reduction of NO

A Pt-free system based on Na/Cu/TiO2 catalysts was used to study the adsorption of NO under lean conditions. The results show that the NO adsorption activity dramatically increased when both sodium and copper are in intimate contact. Although copper is the active phase in the oxidation of NO to NO2, it was found that the addition of sodium species is of vital importance on the subsequent adsorption of NO2, which mainly occurs on the surface of the alkali in the form of nitrates and nitrites. It was found that a loading increase of the alkali led to an increase in the reduction temperature of the copper phase, which is ascribed to a close interaction between the copper and the sodium phases. Among the Na loadings that were studied, the addition of 5% Na gave the optimum adsorption of NO. After successive cycles of adsorption, the catalysts were fully regenerated at temperatures higher than 250 °C using either CO or H2 as a reducing agent.

Figure optionsDownload as PowerPoint slideHighlights▸ Na/Cu/TiO2 catalysts were studied in the adsorption of NO under lean conditions. ▸ The adsorption of NO occurs with the gradual formation of nitrates/nitrites. ▸ An increase in Na loading increased the reduction temperature of the copper phase. ▸ The NO adsorption activity is facilitated by Cu and Na being in close interaction. ▸ CO and H2 fully regenerated the catalysts in successive cycles of operation.