Subnanometric Platinum-Germanium Clusters for Efficient Propane Dehydrogenation Catalysis

Propane dehydrogenation has been a key technology with great industrial promise for meeting the growing global demand for propylene. Although much effort has been devoted to developing ideal catalysts that demonstrate high catalytic activity, selectivity, and durability at the same time, there have been few reports on the achievement of this goal due to a persistent tradeoff between activity and selectivity/stability. Herein, we report that subnanometric Pt─Ge alloy clusters encapsulated in pure silica MFI zeolite can break the activity-stability tradeoff in propane dehydrogenation. We also discovered that MnO_x could act as an efficient co-catalyst to reach the full potential of Pt─Ge alloy clusters by preventing hydrogen poisoning. The MnO_x-PtGe@MFI catalyst exhibited exceptionally high catalytic activity, selectivity, and durability in the absence of co-fed hydrogen (for stabilization) at 600°C, exceeding those of other reported catalysts. Mechanistic study revealed that the combination of subnano-downsizing, alloying Pt clusters with Ge, and hydrogen release by MnO_x was the origin of the exceptional performance.