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

摘要

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. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.