Ammonia Oxidation on Structured Composite Catalysts

Copper based catalysts for the selective ammonia oxidation into nitrogen and water vapour—Recent trends and open challenges

“…4NH3 + 3O2  2N2 + 6H2O (2) So called guard catalysts, ammonia slip catalysts (ASC) or ammonia oxidation catalysts (AMOX) facilitate an overdosing of NH3 increasing the NOx conversion in the reduction system [33,53]. However, despite several studies devoted to catalysts for a selective ammonia oxidation, a catalyst possessing high activity and selectivity over the required temperature range has not been presented yet.…”

“…113,117] 33,126]. We summarized the catalytic performances of these catalysts (Table 2) as well as their physicochemical properties (Table 3).…”

“…Despite high catalytic activity of both catalysts with full ammonia conversion at about 250C, N2O formed in significant quantities in the temperature range of 200-350C. Poor selectivity to N2 was also reported over mixed washcoat catalysts, such as Pt/Al2O3 and Cu/ZSM-5 [33] as well as Pt/Al2O3 and Cu/CHA [126,148,162]. Shrestha et al [33] provided interesting insights into the basic working concept of dual-layer catalysts.…”

“…Poor selectivity to N2 was also reported over mixed washcoat catalysts, such as Pt/Al2O3 and Cu/ZSM-5 [33] as well as Pt/Al2O3 and Cu/CHA [126,148,162]. Shrestha et al [33] provided interesting insights into the basic working concept of dual-layer catalysts. They underlined the trend of increasing selectivity to N2 with increasing copper loading of Cu/ZSM-5, in the same high temperature regime.…”

“…The application areas for NH3-SCO include for instance the treatment of waste gases from chemical production processes, ammonia slip from the NH3-SCR process and gasification of biomass [e.g. [33][34][35][36][37][38]. The desired products of NH3-SCO are nitrogen and water vapour, while nitrogen oxides (N2O, NO) are side-products [39].…”