Reducing the NOx emissions during NH3 oxidation with Nickel modified Fe2O3-a promising cost-effective and environmentally friendly catalyst for NH3 combustion

Ammonia is considered to be a green energy due to its carbon-free footprint, high energy density, cheap transport costs and so on. However, the problem of NO x (mainly NO/NO 2 ) emissions especially at high temperature (>800 °C) inhibits the energy utilization progress of NH 3 (Such as NH 3 combustion). So, catalytic combustion of NH 3 is supposed to be a promising method to solve this problem but there is a rare report on that. The NO x emissions or N 2 selectivity performances in the NH 3 oxidation process with different catalyst was conducted with Density functional theory (DFT) and experimental studies. Results showed that, when Fe 2 O 3 was used as catalyst, the conversion efficiency of NH 3 was 96.2%, and the selectivity of N 2 was 97.7%, which was higher than oxidation of NH 3 without catalyst. DFT simulation showed that NH 3 and O 2 can be separately adsorbed on Fe (top) of Fe 2 O 3 (001), the adsorption of NH 3 and O 2 were enhanced when they were put on Fe (top) of Fe 2 O 3 (001) at the same time. Meanwhile, the length of inter-atomic bond increased thus creating oxygen vacancy , which promoted the oxidation of NH 3 . Finally, a Ni modified Fe-based catalyst (NiO10%/Fe 2 O 3 30%/Al 2 O 3 60%), full of oxygen vacancy (confirmed with X-ray photoelectron spectroscopy (XPS)), was fabricated with impregnation method. The adsorption of NH 3 and O 2 were further enhanced (confirmed by DFT simulation), the NH 3 conversion efficiency and the N 2 selectivity were stably improved to 96.8% and 100%.