(602c) Identifying Unique Interactions between Transition Metals and Perovskite Surface | AIChE

(602c) Identifying Unique Interactions between Transition Metals and Perovskite Surface


Alayyoub, B. - Presenter, University of Pennsylvania
Vojvodic, A., University of Pennsylvania
Conventional supported metal catalysts are pervasive in chemical industries and energy production; however, they tend to degrade over time, and are generally cost prohibitive [1, 2]. While the search for sustainable alternatives remains an ongoing challenge, a promising class of materials that serve as a suitable candidate are perovskite-based oxides. Due to their flexible physical and catalytic properties, the broader scientific community has shown a universal interest in them [2, 3, 4]. They have been utilized as a general catalyst, and/or support for catalytically active metal particles in thermo- and electrochemical reactions, and even in novel catalyst synthesis methods like metal exsolution [4, 5]. Still, a comprehensive understanding of the electronic properties and stability aspects for the different structures at operating conditions is lacking [6].

In this computational study, we investigate the thermodynamics and particular interactions of atomic transition metal species with the surfaces of host perovskite oxides (ABO3). We considered different ABO3 architectures with distinct A and B-site ions and surface facet terminations, acting as both host and support for selected 4d and 5d transition metals. We perform a detailed analysis of different factors playing a role in the interaction including metal adsorption/doping sites, binding strength and local oxidation environment for the metal/perovskite systems of interest to name a few. Using these we are able to rationalize the interaction strengths and stability of these systems. We propose using this approach to discuss the propensity of these systems towards forming larger supported metal clusters/nanoparticles or, alternatively, maximizing the metal dispersed across a specific perovskite. Figure 1 shows the most stable binding energies for M=Rh, Pd, Pd adsorbed on (A=Ca/Sr/Ba)TiO3; clearly displaying the trends and differences across the supports and adsorbed metals. Understanding the nature of these unique interactions would ultimately enable development of superior metal/perovskite catalysts and structures.