Theoretical insights into Pt-Rh alloy nanoparticles: stability, elemental distribution, and catalytic mechanisms for NO plus CO reactions

YZ Li and XB Duan and Z Liu and CR Li and FW Ye and ZH Zhang and LQ Chen and C Du and QB Wang and B Shan, CATALYSIS SCIENCE & TECHNOLOGY, 14, 6286-6297 (2024).

DOI: 10.1039/d4cy00755g

Pt-Rh bimetallic alloys hold significant promise in catalysis. This study theoretically delves into the stable configurations and elemental distributions of Pt-Rh alloy nanoparticles (NPs) and their influence on the NO + CO catalytic reaction. Initially, a comprehensive dataset for the Pt-Rh system is compiled via calculations based on density functional theory (DFT), followed by developing machine learning potential with accuracy akin to DFT. By employing hybrid Monte Carlo/molecular dynamics simulations, the study unveils that the octahedron-shaped NP is the most stable. Elemental distribution analysis highlights the prevalence of Rh atoms within the interior, particularly in the sub-surface layer, with Pt atoms predominantly occupying the top- surface layer. Building upon these insights, four surface models are crafted and their catalytic efficacy in the NO + CO reaction is evaluated via DFT calculations. The findings indicate that Pt atoms at the top-surface foster N2 recombination, Rh atoms facilitate NO dissociation, while Rh atoms in the sub-surface layer modestly enhance both processes. Hence, Pt-Rh alloy NPs featuring surfaces with both Pt and Rh atoms, with a dominance of Rh atoms in the sub-surface layer, are poised to demonstrate bifunctional catalytic prowess in the NO + CO reaction. This study offers crucial guidance for designing bifunctional catalysts for exhaust gas treatment. Pt-Rh alloy nanoparticles featuring surfaces with both Pt and Rh atoms are poised to demonstrate bifunctional catalytic prowess in the NO + CO reaction.

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