MWCNTs-Supported Pd(II) Complexes with High Catalytic Efficiency in Oxygen Reduction Reaction in Alkaline Media

We report here the remarkable catalytic efficiency observed for two Pd(II) azamacrocyclic complexes supported on multiwalled carbon nanotubes (MWCNTs) toward oxygen reduction reactions. Beyond a main (>90%) 4e(-) process and an onset potential close to or better than those of commercial Pt electrodes, the MWCNTs functionalization strategy, aimed at chemically defined Pd(II)-based catalytic centers, allowed the half cell to exceed the proton-exchange-membrane fuel-cell reference/target mass activity efficiency set by the U.S. Department of Energy for 2020 (440 mA/mg(PGM) at 0.9 V vs reversible hydrogen electrode).