Influence of Mn incorporation on oxygen evolution activity of Ir–Mn catalysts in alkaline media

Abstract This study reports the synthesis, structural characterization, and electrocatalytic performance of Ir–Mn alloys for the oxygen evolution reaction (OER) in alkaline media. Ir x Mn y catalysts were prepared using the arc melting, enabling the formation of homogeneous bulk alloys with controlled composition. The results show that catalytic performance is strongly composition-dependent, with Ir-rich samples exhibiting superior activity compared to Mn-rich alloys. Among the investigated materials, Ir 55 Mn 45 demonstrated the best performance, achieving a low overpotential of 320 mV at 10 mA cm −2 , and stable operation for over 22 h in 1 M KOH. In contrast, increasing Mn content led to decreased activity, likely due to the formation of less active surface species under OER conditions. These findings indicate that while Mn incorporation influences the electrochemical behavior of Ir-based alloys, higher Mn concentrations are detrimental to OER performance. This work provides insight into the compositional limitations of Ir–Mn systems and highlights the importance of optimizing alloy composition for alkaline OER catalysis.