Catalytic Reduction of SO₂ by CO over Pt_lAu_m(CO)_n: A First-Principles Investigation

Abstract

The catalytic activities, to the reduction of SO 2 by CO, of clusters Pt l Au m (l + m = 2) with or without preadsorbing CO molecules are investigated using firstprinciples density functional theory. We find that the PtAu(CO) n (n = 1−3) clusters show more excellent catalytic properties than either pure metallic catalysts. Preadsorption of CO to the catalysts could effectively avoid platinum-based catalyst sulfur poisoning; as more CO molecules preadsorbed to the catalysts, the energy barriers for the carbonyl sulfide (COS) molecule's desorption from the catalyst are remarkably decreased. We propose an ideal catalytic cycle to simultaneously get rid of SO 2 and CO over the catalysts PtAu(CO) 3 .

Binding of multiple SO2 molecules to small gold cluster anions (AuN−, AuNOH−, N = 1‐8)

“…To this end, there has been a major effort to develop catalysts with the ability to efficiently dissociate SO 2 by reduction to elemental sulfur . Oxide‐supported gold nanoparticles catalyze a variety of reactions, and recent work has been focused on the potential of these catalysts to react with SO 2 , as well as to understand how SO 2 can hinder the ability of the catalysts to perform other reactions .…”

Catalytic role of pre-adsorbed CO in platinum-based catalysts: the reduction of SO2 by CO on PtlAum(CO)n

“…A larger E des means the catalysts are poisoned by COS (see ref. 26). As the number of pre-adsorbed CO molecules increases (n 4 1), the spin multiplicity of Pt 2 (CO) n turns into a singlet, which weakens the interactions between the COS and the catalyst.…”

“…18,22 Lots of researchers have demonstrated that the Pt/Au alloys and their bimetallic clusters show superior catalytic properties to the individual components. 15,[23][24][25][26][27] However, the real catalytic reaction is a rather complicated process. The understanding of the mechanism of PtAu bimetallic catalysts is still in its initial stages.…”

“…In the absence of a support or solvation, gas-phase computational investigations can provide a conceptual framework and an efficient means by which to obtain direct insight into reaction patterns, the importance of electronic structure, and the nature of crucial intermediates. In our previous study, 26 we have investigated the geometries of various active catalytic sites for PtAu based catalysts, and their application in the catalytic reduction of SO 2 by CO. The compound PtAu(CO) 3 demonstrates excellent catalytic performance: it can not only decrease the activation barrier, but also protect the catalyst from sulfur poisoning.…”

Recovery of elemental sulphur via selective catalytic reduction of SO 2 over sulphided CoMo/γ-Al 2 O 3 catalysts

“…Several catalysts, such as Pt-Au bimetallic catalyst [12,14], La 2-O 2 S catalyst [15,16], were developed for the selective reduction of SO 2 . In spite of good catalytic performance in SO 2 reduction to elemental sulphur using CO as an agent, the use of expensive noble metals and rare earth metals as the active components limits the large-scale use of these catalysts.…”