This work was part of a long-term collaboration between the groups of Charles Sykes (Tufts University), Angelos Michaelides (former TYC Director and Professor at UCL, now at the University of Cambridge) and Michail Stamatakis (UCL). Notably, this collaboration was fostered at a TYC Soirée back in September 2012 and has led to significant advancements in our understanding of SAA catalysts. It has further delivered catalyst formulations that could address current inefficiencies in the catalyst industry and could result in large economic and environmental payoffs.
Alkanes are highly stable chemical species, and thus, converting them to more useful products is a long-standing challenge in the catalysis field. Such a conversion of significant practical importance is the dehydrogenation of propane to propylene, which is a key intermediate in the manufacture of plastics, fabrics and other chemicals, and is in short supply. The prevalent method of producing propylene is steam cracking, which is one of the most energy-intensive industrial processes. These challenges motivate the discovery of novel catalysts that can perform alkane dehydrogenation efficiently, thereby promoting sustainability in chemical process design.
To this end, Stamatakis, Sykes and co-workers focused their studies on single-atom alloy (SAA) catalysts: materials in which a dopant metal is mixed with a host metal at such high dilutions that it remains atomically dispersed. Quantum chemistry methods, specifically density functional theory calculations, were first adopted to identify promising SAAs. The calculations predicted the Rh/Cu SAA to be an excellent catalyst for alkane dehydrogenation, contrary to the known poor behaviour of Rh nanoparticles supported on metal oxides towards this reaction, due to the reactants binding too strongly to the metal. The theoretical predictions were subsequently confirmed by experiments, which demonstrated the Rh/Cu SAA to be an active, selective and stable catalyst for propane dehydrogenation to propylene.
Hannagan et al. 2021, Science 372(6549): 1444-1447
The paper is featured on news releases from Tufts University as well as UCL and highlighted in This Week in Science: