Orthorhombic (Ru, Mn)2O3: A superior electrocatalyst for acidic oxygen evolution reaction

The development of efficient oxygen evolution reaction (OER) electrocatalysts is of vital importance for acidic water decomposition. Currently, the rutile structured RuO2 is considered to be the best candidate and has been studied widely. However, the state-of-the-art rutile RuO2 still suffers from unsatisfactory activity and stability, while other crystalline structures of Ru-based oxides are seldom reported as OER electrocatalysts. The present work, for the first time, successfully synthesizes orthorhombic (Ru, Mn)2O3 electrocatalyst through cation exchange. The orthorhombic (Ru, Mn)2O3 particles exhibit the outstanding electrocatalysis performance as OER electrocatalyst, showing an ultralow overpotential of 168 mV at 10 mA cm−2 in acidic water and good stability in 40 h of OER. The outstanding electrocatalysis performance is attributed to the distinct Ru d-band structure together with the larger surface density of Ru active site, which reduces the free energy of the rate-limiting step during OER.