Enhanced activity for oxygen reduction reaction of π-π self-assembled Co2Pc2(EP)4/RGO catalysts

The development of ORR catalysts that combine high activity with low cost is essential for advancing the practical implementation of related technologies. In this work, an ORR catalyst Co 2 Pc 2 (EP) 4 /RGO was successfully synthesized via a facile π-π self-assembly approach, where spherical binuclear metallophthalocyanine (Co 2 Pc 2 (EP) 4 ) was loaded onto the surface of reduced graphene oxide (RGO). The structural and morphological characteristics of Co 2 Pc 2 (EP) 4 /RGO were systematically investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Electrochemical performance tests showed that the onset potential ( E 0 ) of Co 2 Pc 2 (EP) 4 /RGO was comparable to that of commercial Pt/C, while the half-wave potential (E 1/2 ) of Co 2 Pc 2 (EP) 4 /RGO exhibited a positive shift of 130 mV compared to that of pure Co 2 Pc 2 (EP) 4 . The electrocatalytic activity of Co 2 Pc 2 (EP) 4 / RGO dramatically enhanced because of π-π interactions between Co 2 Pc 2 (EP) 4 and RGO, which promoted the oxygen molecules concentration around the active sites. The high oxygen molecules concentration is conducive to form an intermediate O 2 ads - Co 2 Pc 2 (EP) 4 @RGO to decrease the activation energy of the *OOH dissociation step in a four-electron ORR process and the oxygen molecules could be reduced more easily. This study offers a new direction for the design of oxygen reduction reaction catalysts.