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 (E_O). 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.