2D materials have unusual electron, mechanical and optical properties and have been extensively studied, particularly in the last twenty years, for a diversity of applications. The majority of these studies have focused on graphene; there have been far fewer investigation on non-carbon 2D materials. Typical 2D materials show improved properties to their thicker analogues, as they tend to be flexible, transparent, and are readily modified by surface chemistry. MXenes are metal and nitrogen or carbon in an ultrathin sheet that represent the 2D analogue to “MAX” phases (metal, aluminum and carbon or nitrogen). These materials have the potential to be useful as catalysts in a number of reactions. Iowa State University researchers have optimized MXene catalysts based on Pt/Ti3C2 and Pt/Nb2C architectures for two important reactions; the water gas shift reaction (WGS) and propane dehydrogenation.
WGS is used in the manufacturing of ammonia, hydrocarbons, methanol and hydrogen and thus has significant market potential. The MXene developed by ISU researchers has been shown to be a selective catalyst for the WGS. The catalyst has a lower activation energy and lower frequency than reported literature values for WGS catalysts and enjoys many of the potential benefits typical of 2D materials. This material represents one of the first examples of a MXene catalyst for the WGS reaction.
Shale gas contains large amounts of propane gas, the dehydrogenation of which yields propylene. Propylene is the second most abundant polymer, thus the dehydrogenation of propane into propylene represents an enormous market opportunity. Propane dehydrogenation catalysts have been highly valued and extensively researched, however the majority of research has been on typical "3D" materials. ISU's MXene based catalyst has state of the art selectivity and conversion percentage when compared to reported literature values for propane dehydrogenation. These catalysts significatnly increases propylene selectivity (98%) compared to pure Pt catalysts (85%) at similar conversion.