(294c) Characterizing the Interplay between Molecular-Surface Interactions, Catalyst Reconstruction, and Performance: Hydrogen Oxidation over Pt-Based Bimetallic Catalysts

To sustainably address our energy and chemical needs, new fundamental chemistries and technologies are required that will enable creation of new “oil” and chemical feedstocks from carbon neutral sources like biomass. This requires effective multi-functional catalysts as the biomass-derived feedstocks are highly diverse. Multi-metallic catalysts leverage the properties of multiple metal components to offer improved catalytic performance for a range of applications, but the rapid and rational design of such catalysts is complicated by the tendency of such catalysts to reconstruct in response to the high adsorbate coverages present under realistic reaction conditions. Thus, there is a critical need for fundamental insight into the interplay between adsorbate-adsorbate, adsorbate-metal, and metal-metal interactions, as such interactions provide the driving force for surface reconstructions. Here, we combine density functional theory with microkinetic modeling over a single, multi-facetted, PtM (M = Au, Ru, and W) catalytic grain to characterize the interplay between the metals and adsorbates coverage distributions in a nanoparticle surface under realistic conditions. Using hydrogen oxidation as a case study (Figure 1), the addition of a second metal with increasing oxophilicity to the Pt nanoparticle significantly alters the equilibrium surface coverages of H*, O*, and OH*, with the PtW system seeing high coverages of acidic OH* form selectively on the (110) facets. Overall, this work provides us a deeper understanding of how the nano-scale interactions between adsorbates and bimetallic surfaces drive the metal and adsorbate distributions on catalyst surfaces, as well as enable the real-world tuning of surface composition in bimetallic surfaces via applied gas phase carbon and oxygen chemical potentials.