A Rhenium Single-Atom Catalyst for the Electrocatalytic Oxygen Reduction Reaction.

Single atom catalysts (SACs) have received a great deal of attention due to their extremely high active site utilization and superior activities. The exploration of metal SACs has been carried out by screening the elemental periodic table from first-row to second-row, and even third-row transition metals. However, Re SACs have not been reported, even if Re metal sites also play essential roles in catalyzing many important reactions. The construction of Re SACs may maximize Re catalytic sites and provide new Re active sites for higher activity. Herein, we used 1,10-phenanthroline to complex Re cations on carbon black, followed by heat treatment to obtain Re SAC. The Re SAC exhibited an oxygen reduction reaction (ORR) half-wave potential of 0.72 V versus reversible hydrogen electrode (RHE) in 0.1 M KOH, superior to Re nanoparticles catalyst (0.67 V vs. RHE). Re SAC exhibited better stability at 0.5 V vs. RHE than Pt/C, showing potential as a new electrocatalyst for ORR.