NO reduction by CO under oxidative conditions over CoCuAl mixed oxides derived from hydrotalcite-like compounds: Effect of water

Oxyfuel combustion is a promising technology to produce CO2 rich effluents. Nevertheless, storage as well as valorization steps require to increase the purity of these CO2 rich effluents due to the presence of CO and NOx produced during combustion process. In view of development of transition metal-based catalyst for this application, cobalt and/or copper derived hydrotalcite materials were used as precursor of oxide catalyst for NO-CO abatement in a gas stream similar to those obtained when an oxyfuel combustion is performed. Hydrotalcite precursors and catalysts were characterized by several techniques. The best catalytic performances for the NO-CO abatement are obtained with cobalt-aluminum mixed oxide catalyst. The impact of water was also investigated and following trends were obtained: (i) a decrease in activity for NO oxidation while no modification was observed for CO oxidation; (ii) a shift towards higher temperature for NO reduction while maintaining the same yield; (iii) an improved stability of the catalyst with time on stream