Stabilizing the isolated Pt sites on PtGa/Al2O3 catalyst via silica coating layers for propane dehydrogenation at low temperature

Abstract

Catalytic conversion of propane to propylene can be achieved by non-oxidative propane dehydrogenation (PDH) by Pt-based catalysts under 550–700 °C. In this work, we report a strategy to decrease the Pt loading amount to only 0.1 wt% for obtaining a stable catalyst via silica coating for high PDH activity at a temperature as low as of 450 °C. The as-prepared 2.5%Si@PtGa/Al2O3 catalyst shows outstanding catalytic activity (propylene productivity rate 0.5 mol/gcat.·h) close to its equilibrium conversion (24.5%) with much better stability (deactivation constant: 0.007 h−1) at 450 °C. The interface between catalyst and silica coating changes the strong metal-support interaction (SMSI) to immobilize the Ga oxide clusters, further tightly anchoring the Pt catalytic sites for PDH process. Moreover, the electronic state of Pt is also influenced by the silica coating layers. This work demonstrates a new method to harnessing the metal-support interaction in catalysis.