Oxygen plasma induced interfacial CoOx/Phthalocyanine Cobalt as bifunctional electrocatalyst towards oxygen-involving reactions

Performance of electrocatalysts towards oxygen-involving reactions is strongly associated with the surface and interface properties. Cobalt phthalocyanine (CoPc) materials have been widely explored as oxygen-involving electrocatalysts but their intrinsic catalytic activity is always poor. We present here a surface oxygen plasma approach to directly treat CoPc for producing interfacial CoOx nanodots anchored on CoPc (CoOx/CoPc), which exhibits high activity towards both oxygen reduction reactions (ORR) and oxygen evolution reactions (OER). The optimized CoOx/CoPc demonstrates a much better catalytic activity with a half-wave potential of 0.63 V and an average electron transfer number of 3.64 than the CoPc (0.59 V and n = 2.37) towards ORR in alkaline media. Moreover, OER performance of the CoOx/CoPc is also significantly enhanced, showing a current density of 22.2 mA cm−2 that is 36 times higher than that of CoPc (0.6 mA cm−2) at an overpotential of 0.49 V. It is found that the enhanced performance of the CoOx/CoPc is attributed to the high electrochemical active surface area, highly active CoOx, as well as desired interfacial structure.