Tuning low-temperature N₂O decomposition over Ni-Y-modified cobalt Spinels

Nitrous oxide (N₂O) is a potent greenhouse gas and a major ozone-depleting substance in the modern atmosphere, and the development of efficient low-temperature catalysts for its abatement is of significant industrial relevance. In this work, a ternary NiY co-modified cobalt spinel catalyst (NCY) was synthesized via a controlled co-precipitation route to tune the surface reactivity of Co₃O₄ toward N₂O decomposition. The NCY catalyst exhibits superior low-temperature performance, achieving over 90% N₂O conversion at 400 °C with a low apparent activation energy of 52.77 kJ mol^-1, markedly outperforming the corresponding binary catalysts. Structural and surface analyses indicate that Ni incorporation modifies the redox-responsive surface environments of cobalt oxides, while Y³⁺ contributes to lattice stabilization and structural robustness under reaction conditions. In situ FTIR, mass spectrometry, and ¹⁸O isotope-tracing experiments reveal dynamic surface oxygen exchange during O₂ formation, consistent with a surface-mediated N₂O decomposition pathway dominated by adsorption, dissociation, and suprafacial oxygen recombination. The cooperative effect of Ni and Y therefore tunes surface oxygen behavior and enhances catalytic efficiency at low temperatures, providing a practical strategy for improving N₂O abatement over cobalt spinel catalysts.