Unlocking NO resistance in low-temperature N2O decomposition: The critical role of zeolite with rare earth-modified Co3O4.

Cobalt-based catalysts exhibit high activity for nitrous oxide (N2O) decomposition, but their sensitivity to the nitrogen oxides (NOx) in exhausts strongly hinders practical application. In this study, a gadolinium‑cobalt (GdCo) oxide catalyst supported on MOR (Mordenite) zeolite was developed. Under rigorous conditions containing 7 vol% N2O, 1000 ppm NO, 5 vol% H2O, 10 vol% O2, and a gas hourly space velocity (GHSV) of 10,000 h-1, the 15Gd1Co10Ox/MOR catalyst achieved 100% N2O conversion at 350 °C, exhibiting excellent low-temperature activity and outstanding NO tolerance. The incorporation of Gd modulates the electronic structure of cobalt via Gd-O-Co bridges, which facilitates NO bond cleavage and activates lattice oxygen, thereby establishing a low-energy oxygen recombination (O-OL) pathway that effectively overcomes the rate-limiting O2 desorption step. Furthermore, the Brønsted acid sites on the MOR support play a key role in enhancing NO resistance by selectively adsorbing NO molecules, thereby effectively protecting the Co3+ active sites essential for N2O decomposition. Meanwhile, the active oxygen species (O⁎) derived from N2O dissociation react with adsorbed NO to form NO2, which not only maintains the catalytic cycle but also lays a foundation for subsequent selective catalytic reduction (SCR) processes. This synergistic mechanism between GdCo oxide and the MOR zeolite enables highly efficient and stable N2O decomposition in NO-containing atmospheres, providing a promising strategy for designing industrial catalysts for ultra-low emissions from nitric/adipic acid production and other related chemical processes.