Eu-doped nickel oxide for low-temperature direct decomposition of nitrous oxide

Nitrous oxide (N₂O) is a potent greenhouse gas with high global warming potential. It is urgent to develop active and stabile catalysts for N₂O direct catalytic decomposition (deN₂O) in industrial exhaust gas. In this study, a series of Eu-doped NiO catalysts were synthesized by co-precipitation method. The catalyst with an Eu to Ni molar ratio of 0.04 showed the highest deN₂O ability, reaching 100 % conversion at 400 °C without generating NO_x by-products. The catalyst also displayed resilience against O₂ and NO impurity gases, maintaining structural stability and achieving complete transformation of N₂O at 440 °C. Eu was uniformly dispersed in NiO in the form of Eu₂O₃, which not only regulated the particle size and specific surface area of NiO, but also changed the surface chemistry of NiO by inducing more Ni²⁺ active sites and more mobile O_β species. Eu-doping altered the decomposition mechanism of N₂O from L-H to E-R mechanism, reducing the energy barrier of O₂ desorption, which was the rate-determining step. During the reaction, Eu_0.04Ni showed an activation behavior after cyclic use and long-term reaction and reduced T₁₀₀ to 320 °C after 14-hr experiment. These findings demonstrate the potential of the catalyst for practical application and provide new routes for the direct decomposition of N₂O in industrial exhaust gas.