Boosting CeO 2 /Co 3 O 4 Heterojunctions Acidic Oxygen Evolution via Promoting OH Coverage

Developing nonprecious metal catalysts with excellent activity and durability for the oxygen evolution reaction (OER) in acidic media is essential for the production of hydrogen from proton-exchange membranes (PEMs). However, challenges remain due to the lack of activity and stability of catalysts for OERs. Here, we report that a carbon-coated CeO 2 /Co 3 O 4 heterojunction has a lower overpotential of 425 mV at 10 mA cm –2 than CeO 2 /Co 3 O 4 (489 mV), and Co 3 O 4 (506 mV). Moreover, stability is observed for 50 h. Using in situ electrochemical impedance spectroscopy, the carbon cladding was found to increase the OH coverage and prevent acid corrosion, thereby improving the activity and stability. This provides a pathway for designing nonprecious acidic OER catalysts.