The strength of interaction between a metal and oxygen or carbon is an important criterion for the selection of catalysts for a variety of processes. For example, metals are used to scrub out oxygen in several redox reactions and are also used as catalysts in cross-coupling reactions. In these cases, the effectiveness of the catalyst depends on the oxophilicity and carbophilicity of the metals. Therefore, it is important to understand the factors that determine how oxophilic and carbophilic a metal is. In addition to aiding in catalyst design, understanding these fundamental issues has wide-ranging implications, such as explaining why gold pieces of jewelry do not tarnish and why certain metals coke faster than others under the same conditions. Further, this understanding will aid in designing surfaces that are stable under harsh conditions. In this work, we elucidate the factors that control how oxophilic or carbophilic a metal is by leveraging a variety of data sets for metals across the periodic table.
Generally, single properties such as electronegativity or the d-band center have been heavily relied on to explain trends in oxophilicity. While these factors can explain trends within certain regions of the periodic table, a more general understanding remains elusive. In this work, we developed models to understand what properties are responsible for oxophilicity and carbophilicity in metals. We quantify oxophilicity and carbophilicity using several data sets, including DFT-calculated adsorption energies and experimental formation energies. Our model brings new insight into the mechanism of adsorption on free metals and accurately captures oxophilic and carbophilic trends for metals across the periodic table, including transition metals and non-transitional metals.
