Carbon Nanotubes Confined PtIn Alloy as a Highly Stable Catalyst for Propane Dehydrogenation

A modified impregnation technique was used to prepare carbon nanotube-confined InPt-based catalysts with varying In content. The findings of physicochemical characterizations, such as X-ray diffraction, N2 adsorption/desorption isotherms, H2-temperature programmed reduction, high-resolution transmission electron microscopy, thermogravimetric/differential thermal analysis, Raman, X-ray photoelectron spectroscopy, and CO probed in situ diffuse reflectance Fourier transform infrared, revealed that the addition of the second metal In restricted the agglomeration of active sites during the reaction and successfully lowered the reduction temperature of active metals. The structure and electronic characteristics of the platinum species were altered as a result of the creation of an alloy between platinum and indium. The presence of In species diluted the surface Pt species and transferred electrons to the Pt species, resulting in improving the catalytic activity and suppressing the C–C bond breakage simultaneously, which was beneficial to improve the selectivity of propylene. The apparent activation energy of 0.5InPt/CNTs-catalyzed propane dehydrogenation decreased from 120.0 to 57.2 kJ/mol when compared to that of Pt/CNTs, and the propane conversion rose by 4.3 times from 3.8 to 20.1%, while also demonstrating superior catalytic stability.