A Composite of Pyrrole‐Doped Carbon Black Modified with Co3O4 for Efficient Electrochemical Oxygen Reduction Reaction

Low‐cost catalysts with high performance toward the oxygen reduction reaction (ORR) in energy conversion systems are intensively desired. Here, we report the preparation of a composite catalyst that is composed of pyrrole‐doped carbon black (py‐CB) and Co3O4 nanoparticles (NPs). The synergetic effect of Co3O4 and pyrrole on CB particles endows the obtained py‐CB/Co3O4 hybrid with pronounced catalytic activity toward the ORR. The onset potential of the hybrid is 0.88 V vs. RHE and the half‐wave potential is only 60 mV negative from that of the commercial Pt/C catalyst. The diffusion‐limit current density of this catalyst reaches 5.47 mA cm−2, which is very close to that of Pt/C. The electron‐transfer number of ORR on the py‐CB/Co3O4 is 3.9, indicating a desirable four‐electron reduction pathway. Moreover, the hybrid catalyst exhibits a much higher durability toward the ORR than the commercial Pt/C catalyst. The py‐CB/Co3O4 composite catalyst is highly competitive compared to other carbon‐based catalysts, owing to its high activity, excellent stability, and especially the use of inexpensive CB and the ease of preparation. This work may open a new avenue for the design and preparation of ORR catalysts based on cheap and commercially available CB. Catalyst for future energy: A low‐cost and efficient oxygen reduction reaction (ORR) catalyst composed of pyrrole‐doped carbon black and Co3O4 (py‐CB/Co3O4) is developed. The synergetic effect of Co3O4 and pyrrole on carbon black particles endows the obtained py‐CB/Co3O4 hybrid with pronounced catalytic activity toward the ORR.