Exceptionally active and stable RuO2 by constructing p-n heterojunction between Co3O4 and RuO2 for acidic water oxidation

Development of Ru-based electrocatalysts for acidic oxygen evolution reaction without a trade-off between activity and durability remains challenging. Herein, we constructed Co3O4/RuO2 heterojunctions anchored on carbon (Co3O4/RuO2-C) with a low Ru loading (2.74 wt%), in which strong coupled p-n junctions facilitated electron transfer from RuO2 to Co3O4. The Co3O4/RuO2-C demonstrated a low overpotential of 170 mV at 10 mA cm−2 and long-term stability in 0.1 M HClO4 due to its unique structure. The origin of its high performance in acidic OER was revealed by the combination of in-situ attenuated total reflection infrared and Raman tests. Concretely, oxygen generation for Co3O4/RuO2-C was dominated by the adsorbate evolution mechanism, and the introduction of Co3O4 facilitated the redox of RuO2, generating active sites for OER. Theoretical calculations further substantiated that the Co3O4/RuO2 heterojunctions possessed lower energy barriers for OER. This work provides a compelling synthesis route for effective and stable electrocatalysts for acidic OER.