Ball milling as an effective method for improving oxygen evolution reaction electrocatalyst Ca3Co4O9

Misfit-layered Ca 3 Co 4 O 9 was investigated as oxygen evolution reaction catalyst for electrochemical water splitting. Oxygen vacancies can be effectively induced by ball milling as detected by electronic paramagnetic resonance and X-ray photoelectron spectrometer measurements. The electrochemical performance was investigated for the Ca 3 Co 4 O 9 catalysts with different ball milling times. The results show that the sample with the ball milling time of 24 h possesses the best performance due to the induced oxygen vacancies as well as the enhanced specific surface area. This work will provide an effective route to improve the electrochemical oxygen evolution reaction performance of the misfit-layered cobaltates.