Oxygen vacancy-mediated asymmetric Ni–Ov–Co sites for efficient low-temperature N2O decomposition

The environmental persistence and potent greenhouse effect of N 2 O call for efficient catalytic decomposition to address its environmental impact. However, achieving low-temperature N–O bond activation remains challenging due to the difficulty of constructing highly active sites. Herein, spinel cobalt oxides with controlled geometric configurations are successfully fabricated via the incorporation of heteroatoms. The Ni-substituted octahedral Co promotes the formation of oxygen vacancy, generating an asymmetric Ni–Ov–Co structure. Notably, NiCo 2 O 4 catalyst with abundant asymmetric Ni–Ov–Co structure displays remarkable catalytic performance with a T 90 of 340 °C, which is 50 and 140 °C lower than that of comparative Co 3 O 4 and CoAl 2 O 4 catalysts, respectively. Structural characterizations and density functional theory calculation reveal that asymmetric Ni–Ov–Co sites possess high Co–O covalency and strong N 2 O adsorption capacity, thus reducing the energy barriers in the key steps of N–O bond cleavage and O–O bond formation and boosting the catalytic activity. Moreover, the results of the mechanism research demonstrate that N 2 O decomposition on asymmetric Ni–Ov–Co sites follows the Langmuir-Hinshelwood mechanism. This work underpins the design of asymmetric active sites in spinel oxides as efficient catalysts for greenhouse gas removal.