Enhancing Oxygen Evolution Reaction Activity through Linker Functionalization in Manganese‐Based Metal‐Organic Frameworks (Mn‐MOFs)

Developing efficient and durable electrocatalysts for oxygen evolution reaction (OER) remains a critical bottleneck for economic and large‐scale production of green hydrogen. Metal‐organic frameworks (MOFs) with their unique structural tunability, redox properties, and high surface area have emerged as promising candidates for the OER process. In this work, a presentation on how linker functionalization in rather unexplored manganese‐based MOFs leads to enhanced OER activity is given. A series of manganese‐based MOFs in rarely reported MIL‐88B structure (Mn‐MIL‐88‐X) is synthesized using functionalized linkers [X = NH 2 , NO 2 , Br]. The objective is to modulate the electronic structure and hydrophilicity of the MOFs leading to enhanced OER activity. Among functionalized MOFs, Mn‐MIL‐88‐NH 2 shows remarkable performance, requiring only 260 mV of overpotential to reach a current density of 10 mA cm − 2 and a small Tafel slope of 73 mV dec − 1 . The improvement in OER activity of Mn‐MIL‐88‐NH 2 is ascribed to the higher oxidation states of manganese (Mn 3 + /Mn 4 + ) and the presence of the amino group (‐NH 2 ) as confirmed through X‐ray photoelectron spectroscopy (XPS). This work paves the way for the designing and exploring of mixed‐valence state metal‐based MOFs as advanced electrode materials for electrocatalysis.