Support Engineering Strategy to Tackle the Trade-Off between Catalytic Reactivity and H2o2 Selectivity in Electro-Oxygen Reduction

Direct electrochemical reduction of oxygen to hydrogen peroxide has garnered increasing research attention because of its mild and easy operation relative to traditional anthraquinone cycling route. However, currently used carbon supported noble metal electrocatalysts such as Pd and Pt in the form of single atoms or ultrafine nanoparticles greatly suffered from low reactivity and/or selectivity to hydrogen peroxide. We herein report that ultrafine ca. 1 nm Pd nanoparticles that are stabilized on a N and S co-functionalized carbon support (Pd/NSC) display excellent reactivity and H2O2 selectivity toward electro-oxygen reduction reaction. The first-principle DFT calculations revealed that the excellent catalytic properties of the Pd/NSC derived from its moderate HOO* adsorption strength and lower energy barrier for forming H2O2. Our support engineering strategy is expected to open up new opportunities to simultaneously attain high reactivity and H2O2 selectivity in electro-reduction of oxygen.