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

Nitrous oxide (NO) is a potent greenhouse gas with high global warming potential. It is urgent to develop active and stabile catalysts for NO direct catalytic decomposition (deNO) 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 deNO ability, reaching 100 % conversion at 400 °C without generating NO by-products. The catalyst also displayed resilience against O and NO impurity gases, maintaining structural stability and achieving complete transformation of NO at 440 °C. Eu was uniformly dispersed in NiO in the form of EuO, which not only regulated the particle size and specific surface area of NiO, but also changed the surface chemistry of NiO by inducing more Ni active sites and more mobile O species. Eu-doping altered the decomposition mechanism of NO from L-H to E-R mechanism, reducing the energy barrier of O desorption, which was the rate-determining step. During the reaction, EuNi showed an activation behavior after cyclic use and long-term reaction and reduced T 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 NO in industrial exhaust gas.