Periodic Reporting for period 2 - E-SAC (Evolving Single-Atom Catalysis: Fundamental Insights for Rational Design)
Berichtszeitraum: 2021-08-01 bis 2023-01-31
Single-atom catalysis is a rapidly emerging area of catalysis research in which the amount of precious metal is reduced to a minimum through the use of isolated atoms dispersed on an inexpensive support material. As well as conventional catalysis where gas phase reactions are catalysed by a solid catalyst (as in a car exhaust), single atom catalysis has been shown to have applications in photocatalysis (e.g. water splitting) as well as electrocatalysis (fuel cells). In this project we are trying to build up a fundamental understanding of single atom catalysis by investigating how it is that metal adatoms attach to the support material, and how they interact with reactant molecules at the atomic scale. While our results are fundamental in nature, they do deliver insights of relevance to applied catalysis. For example, we have recently shown that we need to rethink which metals are good for which reaction when we enter the single atom regime. This is because the metals become charged when they make chemical bonds to the support, and this strongly affects their reactivity (Science, 2021).
So far we have begun work studying the adsorption of metals on iron oxide and titanium oxide substrates, and we have learned that water is a crucial ingredient for preventing diffusion. We have performed studies of how CO adsorbs on iron oxide supported metals, and compared experimental results directly to theoretical computations. This work resulted in a high profile publication, and we hope it will have significant impact in the field. We have also studied the mechanism of hydroformlyation on iron oxide supported Rhodium atoms, and we hope to publish these results in the near future. A part of this work was to investigate H2 splitting on single atoms, and this was published in ACS Catalysis. We have been developing our high pressure and electrochemical cells, major goals of the project, and have already published work using the former. The latter is now at prototype stage, and the device appears is capable of sealing between the liquid phase and ultrahigh vacuum.
We are developing an ability to control the coordination of metal adatoms on oxide surfaces, which is crucial to their reactivity. This in itself is beyond the state of the art, but we also intend to study the reactivity of our designed catalysts in realistic environments. By the end of the project we hope to identify optimal metal/support combinations for CO oxidation, hydrogenation and hydroformylation. Moreover, we hope to provide benchmark data to identify the active sites on high surface area catalysts made by our collaborators.