Porous carbon cubes decorated with cobalt nanoparticles for oxygen evolution catalysis in Zn‐air batteries

Summary For commercialization of zinc‐air batteries, it is important to replace expensive noble metal catalysts with inexpensive carbonaceous materials. Herein, an efficient oxygen evolution reaction (OER) catalyst composed of a unique porous tunnel carbon cube and cobalt nanoparticles (Co@NPCC) was fabricated to facilitate oxygen diffusion and create electron conduction networks. As an OER catalyst for zinc‐air batteries (ZABs), the resulting Co@NPCC demonstrate enhanced OER activity, similar to that of the benchmark RuO2. In OER performance, Co@NPCC exhibits the excellent mass activity of 49.9 mA mg−1 at overpotential (η) of 0.47 V and the high current density of 91.5 mA cm−2 at 1.75 V (vs RHE), compared to commercial RuO2 catalysts. The use of Co@NPCC as the OER catalyst for ZAB maintains stable charge overpotential with as little as 0.05 V variation during 250 cycles, which extends the stable discharge‐charge cycle performance compared to RuO2. This work highlights a facile approach to fabricate OER catalysts without noble metals for enabling stable charge state and long life ZABs. Herein, we present the possibility of a highly active and low‐cost OER catalyst for ZABs with a stable overpotential during long discharge‐charge cycles, compared to the benchmark RuO2 catalyst. The porous tunnel carbon cubes decorated with cobalt nanoparticles (Co@NPCC) are prepared as efficient OER catalysts. Co@NPCC is designed to promote oxygen diffusion and create electron‐conducting networks. Using Co@NPCC as OER catalyst for Zn‐air batteries maintains stable charge overpotential with 0.05 V variation for 250 cycles.