Utilizing tannic acid and polypyrrle to induce reconstruction to optimize the activity of MOF-derived electrocatalyst for water oxidation in seawater

Compared with splitting purified water, designing active and stable Oxygen evolution reaction (OER) catalysts for seawater electrolysis by an energy-saving method would more conducive to sustainable production of hydrogen. Here, we report a novel Polypyrrole (PPy) and Tannic acid (TA) modified hollow MIL-88(FeCoNi) (HMIL-88@PPy-TA) on Ni foam. HMIL-88@PPy-TA exhibits outstanding activity in alkaline salty water, showing an extremely low overpotential of 244 and 309 mV at 100 and 500 mA cm-2 in 1 M KOH + NaCl, respectively, and long-term durability of at least 100 h. Combing a variety of structural characterization results, the excellent performance could be attributed to modified PPy-TA which would optimize the local electronic structure and induce reconstruction. This discovery not only provides a new way to design efficient OER electrocatalysts for seawater electrocatalysis, but also represents a novel strategy for inducing structural transformation during OER.