Challenges and opportunities in correlating bimetallic model surfaces and supported catalysts

• Strong correlation is observed between bimetallic model surfaces and supported catalysts for hydrogenation reactions.
• Correlation is less clear for reforming reactions.
• Bimetallic catalysts undergo structural changes under in situ reaction conditions.

In this paper, we use the hydrogenation and reforming reactions to demonstrate the success and challenges in correlating bimetallic model surfaces with supported catalysts. For hydrogenation reactions, results from ultra-high vacuum (UHV) experiments and density functional theory (DFT) calculations of model surfaces typically show strong correlation with reactor evaluations of the corresponding supported catalysts. However, such correlation is less clear for reforming reactions, which require a strong bonding of oxygenates on the bimetallic surfaces. One of the challenges is to understand the bimetallic structures and their stability under reaction conditions, which would in turn provide critical input for constructing relevant model surfaces for UHV and DFT studies. In order to truly achieve the design of bimetallic catalysts from first principles, it is essential that the structures of model surfaces are as close as possible to those under reaction conditions.

Pt-Ni-Pt subsurface configuration in an ultra-high vacuum (UHV) environment will change to a mainly Pt-terminated bimetallic particle under hydrogenation reactions and transform to a mainly Ni-terminated particle in ethylene glycol reforming.Figure optionsDownload high-quality image (85 K)Download as PowerPoint slide