(739e) Au/Ni near-Surface Alloys As Potential Direct H2O2 Synthesis Catalysts: A DFT Study

Celik, F. E., University of Wisconsin-Madison
Mavrikakis, M., University of Wisconsin - Madison

In high-volume industrial catalytic processes, increasing catalyst selectivity can have a potentially higher impact on process margins than increasing activity.  The search for metal catalysts possessing high selectivity and activity has led to the evaluation of many types of metal alloys, hoping to combine the high activity of one metal with the higher selectivity of another, less-reactive metal catalyst.  Near-surface alloys (NSAs) are a particular subset of alloys where the alloying is restricted to the top one or two layers of a metal surface.  Au atoms substituted into the surface of Ni (111) have already been shown to possess higher steam reforming selectivity by impeding the formation of carbon [1].

In the present study, periodic, self-consistent Density Functional Theory (DFT) calculations were used to evaluate Au/Ni NSAs as potential oxygen reduction catalysts for the direct synthesis of hydrogen peroxide from O2 and H2, thereby avoiding the current anthraquinone process.  While Au may have higher O-H bond formation activity, it is a poor O2-dissociation catalyst, and likewise Ni is very effective at O2-dissociation but not oxygen-hydrogenation [2].  The Au-substituted Ni (111) shows properties intermediate between pure Au and Ni, such as H atom binding energies.  

[1] F. Besenbacher, I. Chorkendorff, B.S. Clausen, B. Hammer, A. M. Molenbroek, J. K. Nørskov, I. Stensgaard, Science 279 (1998) 1913.

[2] D.C Ford, A.U. Nilekar, Y. Xu, M. Mavrikakis, Surf. Sci. 604 (2010) 1565.