A Bifunctional Electrocatalyst for OER and ORR based on a Cobalt(II) Triazole Pyridine Bis-[Cobalt(III) Corrole] Complex

Abstract

As alternative energy sources are essential to reach a climate-neutral economy, hydrogen peroxide (H2O2) as futuristic energy carrier gains enormous awareness. However, seeking for stable and electrochemically selective H2O2 ORR electrocatalyst is yet a challenge, making the design of—ideally—bifunctional catalysts extremely important and outmost of interest. In this study, we explore the application of a trimetallic cobalt(II) triazole pyridine bis-[cobalt(III) corrole] complex CoIITP[CoIIIC]2 3 in OER and ORR catalysis due to its remarkable physicochemical properties, fast charge transfer kinetics, electrochemical reversibility, and durability. With nearly 100 % selective catalytic activity towards the two-electron transfer generated H2O2, an ORR onset potential of 0.8 V vs RHE and a cycling stability of 50 000 cycles are detected. Similarly, promising results are obtained when applied in OER catalysis. A relatively low overpotential at 10 mA cm−2 of 412 mV, Faraday efficiency 98 % for oxygen, an outstanding Tafel slope of 64 mV dec−1 combined with superior stability.