Design of high efficient oxygen reduction catalyst from the transition metal dimer phthalocyanine monolayer

Abstract Due to the large surface area, unique atomic configurations and dispersed metal sites, metal-organic porous monolayers provide a promising strategy for catalysis. Among them, the transition metal dimer phthalocyanine (TM 2 Pc) monolayer is one of the interesting members. Herein, we studied the oxygen reduction reaction (ORR) of TM 2 Pc with a series of transition metal dimers (M = Mn-Cu and Ru-Pd) by using the density functional theory. Volcano plot suggests that Fe 2 Pc has the best ORR activity. This is also confirmed by thermodynamic and kinetic study. Among the studied TM 2 Pc, Fe 2 Pc has the highest working potential of 0.98 V (smallest overpotential of 0.25 V), larger than 0.78 V for pure Pt. The energy barrier calculations show that for Fe 2 Pc, the rate-determining step is the *OOH hydrogenation to form *OH + *OH with an energy barrier of 0.25 eV, much smaller than 0.80 eV for pure Pt. Therefore, Fe 2 Pc has good ORR activity compared with pure Pt. These results also indicate that the introduction of transition metal dimer on phthalocyanine monolayer would provide a novel strategy for the design of high efficient ORR catalysts.