Characterization and Use of Single-Atom Alloys for Selective Dehydrogenation and Hydrogenation Reactions

Understanding the interaction between metal atoms is crucial for understanding the properties of heterogeneous catalysts and their activity towards selective reactions. Recently, it has been hypothesized that single atom alloys (SAA), single isolated atoms of active metals alloyed into a less active metal matrix, could be capable of driving the same reactions as their bimetallic and monometallic counterparts. The work presented here aims to understand the surface chemistry and properties of these SAAs through the use of model systems that have been prepared, characterized and tested under ultra-high vacuum (UHV) conditions using surface sensitive techniques, including reflection absorption infrared spectroscopy (RAIRS) and temperature programmed desorption (TPD). Specifically, the influence of single Pd atoms towards the selective hydrogenation of acetylene in a Pd/Ag(111) SAA have been explored. CO has been used as a molecular probe and its RAIR and TPD spectra have been used to characterize Pt/Cu(111) bimetallic surfaces and a Pt/Cu(111) SAA. The dehydrogenation of ethanol to acetaldehyde has also been studied on several Pt/Cu(111) bimetallic surfaces.