Selective catalytic oxidation of ammonia to nitrogen over mesoporous CuO/RuO₂ synthesized by co-nanocasting-replication method

A new type of catalyst for ammonia selective catalytic oxidation, mesoporous CuO/RuO₂ with well-crystallized framework and ordered mesoporous structure, has been synthesized by a co-nanocasting-replication method. Various techniques have been employed for the material characterization. The prepared mesostructured bimetal oxides demonstrated high catalytic activity and N₂ selectivity toward NH₃ oxidation reaction in the presence of excess oxygen. The temperature for the complete ammonia oxidation was as low as 180 °C on the mesoporous 10 wt.% CuO/RuO₂ composite, and there was no apparent decrease in the catalytic activity at prolonged reaction time. Both high ammonia conversion up to 100% and high N₂ selectivity (>95%) were achieved on the mesoporous 5-15 wt.% CuO/RuO₂ composites. A synergetic catalytic mechanism between copper and ruthenium component was proposed to understand the promoted catalytic effect, especially the achievement of both high conversion and high selectivity for N₂ by CuO.