Cr ₂ O ₃ /RuO ₂ Heterojunction Catalysts for Enhanced Oxygen Evolution Reaction in Acidic media

Abstract Ruthenium‐based catalysts are currently considered as the promising alternatives to high‐cost iridium‐based catalysts employed for acidic oxygen evolution reaction (OER) but they still faces the bottlenecks of limited durability and slow kinetics. In this study, we synthesized Cr 2 O 3 /RuO 2 heterojunction catalysts via hydrothermal and annealing techniques to address this issue. The synthesized Cr 2 O 3 /RuO 2 catalysts demonstrated a low overpotential of 220 mV in an acidic environment to reach a current density of 10 mA cm −2 as well as stable operation for 100 h. Experimental results show that the introduction of Cr 2 O 3 into the RuO 2 can modulate the electronic structure of RuO 2 , thereby optimizing the adsorption behavior of key intermediates on the Cr 2 O 3 /RuO 2 heterojunction and enhancing its acidic OER performance. These findings provide valuable insights for future efficient acidic OER electrocatalyst design.