Role of the Cu content and Ce activating effect on catalytic performance of Cu-Mg-Al and Ce/Cu-Mg-Al oxides in ammonia selective catalytic oxidation

Catalytic Oxidation of Ammonia over Cerium-Modified Copper Aluminium Zinc Mixed Oxides

“…Among all catalysts listed above, Cu-based materials show good efficiency, and they are still intensively studied. Many types of Cu-containing catalysts have been tested in the last years, showing high activity and selectivity in ammonia oxidation reactions [ 6 , 8 , 19 , 24 , 27 , 28 , 29 ]. The catalytic efficiency of such materials is usually affected by many factors, such as Cu content [ 8 , 29 , 30 , 31 ], preparation method [ 32 ], calcination temperature [ 6 , 30 , 31 ], particle size [ 32 ] or type of support [ 33 ].…”

“…Many types of Cu-containing catalysts have been tested in the last years, showing high activity and selectivity in ammonia oxidation reactions [ 6 , 8 , 19 , 24 , 27 , 28 , 29 ]. The catalytic efficiency of such materials is usually affected by many factors, such as Cu content [ 8 , 29 , 30 , 31 ], preparation method [ 32 ], calcination temperature [ 6 , 30 , 31 ], particle size [ 32 ] or type of support [ 33 ]. However, the copper oxide was often proved to be an active species in the NH 3 -SCO reaction [ 5 , 8 , 29 , 31 , 34 ].…”

“…The catalytic efficiency of such materials is usually affected by many factors, such as Cu content [ 8 , 29 , 30 , 31 ], preparation method [ 32 ], calcination temperature [ 6 , 30 , 31 ], particle size [ 32 ] or type of support [ 33 ]. However, the copper oxide was often proved to be an active species in the NH 3 -SCO reaction [ 5 , 8 , 29 , 31 , 34 ]. Thus, the optimal amount of Cu, as well as nature/type of copper phase, dispersion level, reducibility, and a large number of accessible acidic surface sites, are the parameters that define its catalytic performance [ 5 ].…”

“…In our previous study [ 8 , 29 ], Cu-Mg-Al-(Ce) and Cu-Mg-Fe-(Ce) mixed oxides prepared by hydrotalcite-like precursors, were tested to obtain the NH 3 -SCO catalyst, which would be active and sufficiently selective at temperatures up to 350 °C. The best catalytic performance was achieved using catalysts calcined at 800 °C with Cu loading of 5 and 7 mol.% of total cation content.…”

“…Since the mixed metal oxides obtained by calcination of hydrotalcite-like compounds are very promising materials, they have gained the attention of many scientists. These kinds of materials are characterized by homogeneously dispersed active centers, thermal stability, and relatively high surface area [ 6 , 8 , 11 , 29 , 35 , 36 ]. There is still the effort to find an appropriate catalyst, which is sufficiently active and selective in NH 3 -SCO, by changing its chemical composition and, therefore, the physical-chemical properties.…”