JingguangChen

Thayer Lindsley Professor of Chemical Engineering,

Columbia University, Yew York, NY 10027, USA

 

It is well known that bimetallic surfaces often show novel properties that are not present on either of the parent metal surfaces [1,2]. However, it is difficult to know a priori how the catalytic properties of a particular bimetallic surface will be modified relative to the parent metals. In the past few years our research group has investigated the novel catalytic properties of various bimetallic systems, using a combination of Density Functional Theory (DFT) modeling, surface science studies on single crystal surfaces, and reactor evaluation of supported bimetallic catalysts.

In the current presentation we will use several probe reactions to demonstrate the unique chemical and catalytic properties of bimetallic systems.  We will use the hydrogenation of alkenes, which is a reaction that requires relatively weak bonding of atomic hydrogen and alkenes, to demonstrate the utilization of bimetallic surfaces to enhance the hydrogenation activity [3].  We will also use the selective hydrogenation of the C=O bond in unsaturated aldehydes to illustrate the possibility of controlling the selectivity with bimetallic surfaces [2].  Next, we will present results for controlling the activity and selectivity of bimetallic surfaces for the reforming of oxygenates (alcohols and glycols), which is a reaction that requires relatively strong bonding of both hydrogen and oxygenates [4,5].  Finally, we will present thermodynamic stability and kinetic measurements regarding the stability of bimetallic surfaces in the presence of oxygen and hydrogen [6].  Overall, these results demonstrate the possibility of selecting catalytic materials with desirable activity, selectivity and stability based on the center of d-band of bimetallic surfaces, making it possible to predict bimetallic formations/structures with desirable catalytic properties.   

 

[1]  Hansgen, Vlachos & Chen, Nature Chem. 2 (2010) 484

[2]  Murillo, Goda& Chen, J. Am. Chem. Soc. 129 (2007) 7101

[3]  Lonergan, Vlachos & Chen, J. Catalysis, 271 (2010) 239

[4]  Salciccioli, Yu, Barteau, Chen & Vlachos, J. Am. Chem. Soc.133 (2011) 7996

[5]  Yu, Barteau& Chen J. Am. Chem. Soc.133 (2011) 20528

[6]  Yu, Porosoff& Chen, Chemical Reviews, (2012)DOI: 10.1021/cr300096b.