Dispersed Pr\non Nickel Oxide for Efficient Nitrous\nOxide Direct Decomposition in Simulated Nitric Acid Exhaust

Nitrous oxide (N<sub>2</sub>O) is a potent greenhouse\ngas with\na high global warming potential. The N<sub>2</sub>O direct decomposition\n(deN<sub>2</sub>O) is currently the most widely used technique due\nto its operational simplicity and lack of secondary pollution. The\npresence of impurity gases in industrial exhaust increases the challenge\nof eliminating N<sub>2</sub>O, urging the development of highly active\nand stable catalysts for its degradation. In this study, a series\nof praseodymium (Pr)-doped nickel oxide (NiO) catalysts were synthesized\nfor N<sub>2</sub>O degradation. These catalysts showed higher N<sub>2</sub>O decomposition activity (<i>T</i><sub>100</sub> = 400–440 °C) than pure NiO (<i>T</i><sub>100</sub> = 480 °C) and also demonstrated high resistance to\nimpurity gases in simulated industrial nitric acid tail gas. In the\ncatalyst with a Pr to Ni ratio of 0.002, the highly dispersed Pr on\nthe NiO surface regulated its particle size and increased specific\nsurface area and pore volume. DFT calculations revealed that Pr significantly\nenhanced the electron-donating ability of Ni<sup>2+</sup>, facilitating\nthe dissociative adsorption of N<sub>2</sub>O on the catalyst surface,\nwhere O existed in the form of Ni<sup>3+</sup>-O*. Additionally, Pr\nreduced the desorption energy of O<sub>2</sub>, the rate-determining\nstep. During the reaction, Pr<sup>3+</sup> transferred electrons to\nNi<sup>3+</sup> via f-d electron hopping, stabilizing the active Ni<sup>2+</sup> sites and enabling an efficient catalytic reaction. These\nfindings demonstrate the practical potential of this catalyst and\nprovide new insights into the degradation of N<sub>2</sub>O in industrial\nexhaust gases, offering a promising avenue for application.