Search Directions for Direct H2O2 Synthesis Catalysts Starting from Au12 Nanoclusters

We present density functional theory calculations on the direct synthesis of H2O2 from H2 and O2 over an Au12 corner model of a gold nanoparticle. We first show a simple route for the direct formation of H2O2 over a gold nanocatalyst, by studying the energetics of 20 possible elementary reactions involved in the oxidation of H2 by O2. The unwanted side reaction to H2O is also considered. Next we evaluate the degree of catalyst control and address the factors controlling the activity and the selectivity. By combining well-known energy scaling relations with microkinetic modeling, we show that the rate of H2O2 and H2O formation can be determined from a single descriptor, namely, the binding energy of oxygen (EO). Our model predicts the search direction starting from an Au12 nanocluster for an optimal catalyst in terms of activity and selectivity for direct H2O2 synthesis. Taking also stability considerations into account, we find that binary Au–Pd and Au–Ag alloys are most suited for this reaction.