In-Pt Supported Catalytically Active Liquid Metal Solutions for Propane Dehydrogenation – Role of Surface Acidity of Support

Abstract

Propane dehydrogenation is a dynamic catalytic application associated with rapid deactivation due to coking. Supported catalytically active liquid metal solutions (SCALMS) have been demonstrated to suppress coking due to the highly dynamic active sites at the liquid metal–gas interface. Herein, the parent catalysts for In-Pt SCALMS were prepared by impregnation using a series of alumina supports with various surface acidity. Reduction in hydrogen results in the formation of a supported liquid In-rich alloy, which was studied using in situ X-ray diffraction. The concentration profile of Pt is modeled via machine learning force field molecular dynamics simulation confirming an enrichment of Pt below the surface of the liquid alloy. The SCALMS with the least acidic alumina support results in a superior performance during propane dehydrogenation. In situ high-resolution thermogravimetric analysis coupled with mass spectrometry indicates enhanced coking with increasing alumina acidity, while comparison with a Pt/Al₂O₃-supported catalyst highlights the coking resistance of SCALMS.