Nitrous oxide (N2O) has gained increasing
attention
as an important noncarbon dioxide greenhouse gas, and catalytic decomposition
is an effective method of reducing its emissions. Here, Co3O4 was synthesized by the sol–gel method and single-atom
Pr was confined in its matrix to improve the N2O decomposition
performance. It was observed that the reaction rate varied in a volcano-like
pattern with the amount of doped Pr. A N2O decomposition
reaction rate 5–7.5 times greater than that of pure Co3O4 is achieved on the catalyst with a Pr/Co molar
ratio of 0.06:1, and further Pr doping reduced the activity due to
PrO
x
cluster formation. Combined with
X-ray photoelectron spectroscopy, X-ray absorption fine structure,
density functional theory and in situ near-ambient
pressure X-ray photoelectron spectroscopy, it was demonstrated that
the single-atom doped Pr in Co3O4 generates
the “Pr 4f–O 2p–Co 3d” network, which
redistributes the electrons in Co3O4 lattice
and increases the t2g electrons at the tetracoordinated
Co2+ sites. This coupling between the Pr 4f orbit and Co2+ 3d orbit triggers the formation of a 4f–3d electronic
ladder, which accelerates the electron transfer from Co2+ to the 3π* antibonding orbital of N2O, thus contributing
to the N–O bond cleavage. Moreover, the energy barrier for
each elementary reaction in the decomposition process of N2O is reduced, especially for O2 desorption. Our work provides
a theoretical grounding and reference for designing atomically modified
catalysts for N2O decomposition.