Structural chemistry of the second metal in Pt-M-zeolite catalysts for propane dehydrogenation: from static configurations to dynamic architectures.

Abstract

Propane dehydrogenation (PDH) has become a leading on-purpose propylene production technology, driven by the shale gas revolution and growing global propylene demand. Pt-based catalysts are highly active for C-H bond activation. However, the high cost and scarcity of platinum, together with severe deactivation caused by metal sintering and coke deposition under high-temperature conditions, necessitate more efficient and durable catalysts. An effective strategy is to introduce a second metal (SM) such as Sn, Zn, or Ge into Pt-zeolite systems, forming Pt-M architectures that synergistically enhance catalytic performance. This review systematically analyzes the structural chemistry of SM in Pt-M-zeolite catalysts for PDH. We classify the diverse structures in Pt-M-zeolite systems into nine representative configurations based on SM location, interaction with Pt, and dynamic behavior: framework-substituted, ion-exchanged, alloy or intermetallic clusters, atomic-cluster composites, oxo-bridged Pt-O-M linkages, core-shell motifs, decoration or island-like modifications, dynamically evolving species, and proximal bifunctional sites. For each configuration, we elucidate the structure-function relationships, highlighting how the specific structural organization of SM modulates the geometric and electronic properties of Pt sites. The PtSn system is examined as a special case to illustrate the extraordinary structural diversity achievable with a single SM. Finally, we semi-quantitatively compare Pt-M-zeolite catalysts against non-zeolite counterparts in terms of activity, productivity, and stability. This review places the structural chemistry of SM at the center of the discussion, providing a reference for understanding and rationally designing next-generation Pt-M-zeolite catalysts.

Abstract as supplied by the indexing source. © the authors / publisher.