General trends in the electronic and chemical properties of bimetallic surfaces

COLL 111

Jingguang G. Chen, jgchen@udel.edu, Department of Chemical Engineering, University of Delaware, 332 Colburn Lab, Newark, DE 19716
The formation of bimetallic alloys offers an opportunity to tune the electronic and therefore chemical properties of transition metals. It is well known that bimetallic surfaces, prepared by depositing one metal onto another, often demonstrate novel physical and chemical properties that are not seen in either pure metal alone. In the current talk we will discuss our recent results on this subject using a combination of DFT modeling and UHV studies on model surfaces, and reactor evaluation of supported catalysts [1-4]. We will first provide a correlation of hydrogen binding energy (HBE) with the surface d-band center of a wide range of bimetallic surfaces. We will then use several examples to demonstrate the utilization of HBE values to predict desirable bimetallic systems for hydrogenation (consumption of hydrogen) and reforming (production of hydrogen) reactions. We will also discuss the thermodynamics and kinetics of transformation of bimetallic surface structures in the presence of atomic hydrogen and atomic oxygen. [1] Hwu et al. J. Am. Chem. Soc. 124 (2002) 702 [2] Kitchin et al. Phys. Rev. Lett. 93 (2004) 156801 [3] Kitchin et al. J. Chem. Phys. 120 (2004) 10240 [6] Menning et al. J. Phys. Chem. B, 110 (2006) 15471