Electro-Bendable Metal–Organic Framework Nanosheets Enable Durable Electrocatalytic Water Oxidation at 1 A/cm<sup>2</sup>
Yuanwu Liu, Lirong Wang, Congcong Liu, Johannes Kresse, Marielle Deconinck, René Hübner, Daria Mikhailova, Yana Vaynzof, Xiaoming Zhang, Alexander Eychmüller
Abstract
High Resolution Image Download MS PowerPoint Slide The oxygen evolution reaction (OER) is a pivotal process in electrochemical systems, including metal-air batteries and water-splitting technologies. Despite the promise of metal–organic frameworks (MOFs) as OER electrocatalysts, their stability at elevated current densities (>500 mA cm –2 ) remains a key challenge for industrial applications. Herein, we developed a bimetallic MOF electrocatalyst, Fe 8.47 Ni 91.53 -2-amino-1,4-benzendedicarboxylate (Fe 8.47 Ni 91.53 -BDC-NH 2 ), exhibiting good stability at 1 A cm –2 for 100 h, with overpotentials of only 210 mV at 10 mA cm –2 and 273 mV at 100 mA cm –2 . The enhanced activity of the catalyst originates from the bending of freestanding FeNi-BDC-NH 2 nanosheets toward the nickel foam substrate during the OER, facilitating the formation of enlarged Mott–Schottky regions and accelerating electron transfer. Additionally, the reversible structural transformation of Ni-2-amino-1,4-benzendedicarboxylate (Ni-BDC-NH 2 ) during the OER, coupled with the introduction of Fe ions, effectively prevents the overoxidation of the active β-NiOOH intermediate to γ-NiOOH, further boosting the OER performance. This work provides insights into structural and electronic modifications that enable MOFs to achieve both high performance and stability at industrial current densities.