The Reactivity of Ptn+ Clusters With N2O Facilitated by Dual Lewis-Acid Sites

The size dependence of metal cluster reactions frequently reveals valuable information on the mechanism of nanometal catalysis. Here, the reactivity of the Pt-n(+) (n = 1-40) clusters with N2O is studied and a significant dependence on the size of these clusters is noticed. Interestingly, the small Pt-n(+) clusters like Pt-3(+) and Pt-4(+) are inclined to form N2O complexes; some larger clusters, such as Pt-19(+), Pt-21(+), and Pt-23(+), appear to be unreactive; however, the others such as Pt-3(,)9,15(+) and Pt-18(+) are capable of decomposing N2O. While Pt-9(+) rapidly reacts with N2O to form a stable quasitetrahedron Pt9O+ product, Pt-18(+) experiences a series of N2O decompositions to produce Pt18O1-7+. Utilizing high-precision theoretical calculations, it is shown how the atomic structures and active sites of Pt-n(+) clusters play a vital role in determining their reactivity. Cooperative dual Lewis-acid sites (CDLAS) can be achieved on specific metal clusters like Pt-18(+), rendering accelerated N2O decomposition via both N- and O-bonding on the neighboring Pt atoms. The influence of CDLAS on the size-dependent reaction of Pt clusters with N2O is illustrated, offering insights into cluster catalysis in reactions that include the donation of electron pairs.