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 Co 3 O 4 /RuO 2 heterojunctions anchored on carbon (Co 3 O 4 /RuO 2 -C) with a low Ru loading (2.74 wt%), in which strong coupled p-n junctions facilitated electron transfer from RuO 2 to Co 3 O 4 . The Co 3 O 4 /RuO 2 -C demonstrated a low overpotential of 170 mV at 10 mA cm −2 and long-term stability in 0.1 M HClO 4 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 Co 3 O 4 /RuO 2 -C was dominated by the adsorbate evolution mechanism, and the introduction of Co 3 O 4 facilitated the redox of RuO 2 , generating active sites for OER. Theoretical calculations further substantiated that the Co 3 O 4 /RuO 2 heterojunctions possessed lower energy barriers for OER. This work provides a compelling synthesis route for effective and stable electrocatalysts for acidic OER.