In situ Electroactivated Fe‐NiOOH Nanoclusters on Carbon Quantum Dots for Efficient Large‐Scale Oxygen Production

Abstract

The sluggish kinetics of oxygen evolution reaction (OER) seriously limits the development of water‐based energy devices due to the inevitable loss of activity at high current electrolysis. Herein, an in situ activation of the electrocatalyst of dual metal ions on carbon quantum dots (Fe‐NiOOH/CQDs) for the scalable oxygen production is reported. Through alternating the potential‐determining step and averaging energy barrier distributions of OER, Fe‐NiOOH/CQDs show excellent intrinsic OER performance with an extremely low Tafel slope of 35 mV dec−1 and the overpotential of 199 mV@10 mA cm−2. Meanwhile, the hydrophilicity and aerophobicity of Fe‐NiOOH/CQDs facilitate the rapid OH− diffusion and O2 detachment, resulting in an outstanding kinetics for large‐scale oxygen production. With an overpotential of 450 mV@1000 mA cm−2 and ultrahigh turnover frequency of 5.4 s−1, it is superior to most of the reported transitional‐metal‐based electrocatalysts. Thereby, a water splitting electrolyzer with Fe‐NiOOH/CQDs anode is assembled to demonstrate the promising reality.