• Hutchings, Graham J.
• Freakley, Simon J.
• Ledendecker, Marc
• Malta, Grazia
• Mayrhofer, Karl J. J.
• Fortunato, Guilherme V.
• Pizzutilo, Enrico

Abstract

<p>Palladium nanoparticles have been studied extensively as catalysts for the direct synthesis of hydrogen peroxide, where selectivity remains a key challenge. Alloying Pd with other metals and using acid and halide promoters are commonly employed to increase H₂O₂ selectivity; however, the sites that can selectively produce H₂O₂ have not been identified and the role of these additives remains unclear. Here, we report the synthesis of atomically dispersed PdCl_x/C as a model catalyst for H₂O₂ production without the presence of extended Pd surfaces. We show that these isolated cationic Pd sites can form H₂O₂ with significantly higher selectivity than metallic Pd nanoparticles in both the reaction of H₂ and O₂ and the electrochemical oxygen reduction reaction. These results demonstrate that catalysts containing high populations of isolated Pd sites are selective catalysts for this two-electron reduction reaction and that the performance of materials in the direct synthesis reaction and electrocatalytic oxygen reduction reaction has many similarities.</p>

Topics

• nanoparticle
• surface
• Oxygen
• Hydrogen
• palladium