Local structures and catalytic N2O decomposition properties of Ni1−xCuxCo2O4

This study focuses on the catalytic performance of Ni 1−x Cu x Co 2 O 4 (x = 0.00–1.00) spinel oxides for the direct decomposition of nitrous oxide (N 2 O), a potent greenhouse gas. Ni–Cu–Co spinels were synthesized via controlled precipitation and characterized using X-ray diffraction, Brunauer–Emmett–Teller analysis, X-ray photoelectron spectroscopy, and H 2 temperature-programmed reduction to elucidate the relationship between catalyst composition, catalyst structure, and catalytic activity. Catalytic tests were conducted under 200 ppm of N 2 O, 10% O 2 , and N 2 balance with and without water vapor. Results revealed that partial substitution of Ni by Cu significantly modifies redox properties and oxygen vacancy concentration, thereby enhancing N 2 O conversion. Among the tested compositions, Ni 0.75 Cu 0.25 Co 2 O 4 exhibits the highest activity, achieving nearly complete N 2 O decomposition at ~ 400 °C. Mechanistic insights suggest that Co 2 ⁺–oxygen-vacancy pairs are the primary active sites, whereas Ni and Cu modulate electronic structures and oxygen mobility.