Dispersed Pr on Nickel Oxide for Efficient Nitrous Oxide Direct Decomposition in Simulated Nitric Acid Exhaust

Nitrous oxide (N2O) is a potent greenhouse gas with a high global warming potential. The N2O direct decomposition (deN2O) is currently the most widely used technique due to its operational simplicity and lack of secondary pollution. The presence of impurity gases in industrial exhaust increases the challenge of eliminating N2O, urging the development of highly active and stable catalysts for its degradation. In this study, a series of praseodymium (Pr)-doped nickel oxide (NiO) catalysts were synthesized for N2O degradation. These catalysts showed higher N2O decomposition activity (T100 = 400–440 °C) than pure NiO (T100 = 480 °C) and also demonstrated high resistance to impurity gases in simulated industrial nitric acid tail gas. In the catalyst with a Pr to Ni ratio of 0.002, the highly dispersed Pr on the NiO surface regulated its particle size and increased specific surface area and pore volume. DFT calculations revealed that Pr significantly enhanced the electron-donating ability of Ni2+, facilitating the dissociative adsorption of N2O on the catalyst surface, where O existed in the form of Ni3+-O*. Additionally, Pr reduced the desorption energy of O2, the rate-determining step. During the reaction, Pr3+ transferred electrons to Ni3+ via f-d electron hopping, stabilizing the active Ni2+ sites and enabling an efficient catalytic reaction. These findings demonstrate the practical potential of this catalyst and provide new insights into the degradation of N2O in industrial exhaust gases, offering a promising avenue for application.