Experimental and Theoretical Investigation of Metal–Support Interactions in Metal-Oxide-Supported Rhenium Materials

The activity and stability of supported metal catalysts is significantly influenced by the interactions between the metal and the support, the so-called metal–support interactions (MSIs). Here, we present a systematic study that uses both experimental and computational approaches to investigate MSIs between Re and oxide supports. Re dispersed on SiO 2, Al 2 O 3, and MgO tends to be aggregated whereas Re dispersed on TiO 2, V 2 O 5, ZrO 2, Nb 2 O 5, and CeO 2 exhibits a high degree of dispersion. Electronic properties such as the position of the conduction-band minimum (CBM) of the oxide support, a proxy for the electron affinity (EA), and the Fermi energy ( E F ) of the supported Re, a proxy for the work function (WF), were found to be of particular importance to govern the degrees of dispersion and aggregation of Re. Metal-oxide supports that have an EA that is larger than the WF of Re, such as TiO 2, V 2 O 5, and CeO 2, can accept electrons from Re into their CB, inducing a strong MSI. This results in a large Re adsorption energy ( E ads ) that leads to a high degree of dispersion for the supported Re metal. Our work describing the electronic interactions that govern the degree of dispersion will enable the synthesis of active and durable catalysts via the identification of suitable combinations of metals and oxides.