2D coordination polymers of transition metals as catalysts for oxygen evolution reaction

Abstract

The oxygen evolution reaction (OER) is a key process in water splitting for hydrogen production, yet its sluggish kinetics pose significant challenges for catalyst development. In this work, we present the first systematic study on isostructural 2D coordination polymers (CPs) based on 1,1′-ferrocenediyl-bis(H-phosphinic) acid, with cobalt, manganese, and cadmium metals as electrocatalysts for OER. These polymers were synthesized via a facile solution reaction, yielding crystalline materials with excellent structural integrity. The electrocatalytic performance of CPs composites, prepared with carbon and phosphonium ionic liquid, was evaluated in 0.1 M KOH using a three-electrode system. Notably, the Co- and Cd-based CPs demonstrated exceptional OER activity, achieving an overpotential as low as 236–255 mV at 10 mA cm⁻², surpassing those of many previously reported CP-based OER catalysts. Furthermore, these materials exhibited high stability over prolonged electrolysis, maintaining their activity without significant degradation. This work not only introduces a new class of ferrocenyl phosphinate-based CPs as highly active and durable OER catalysts but also provides valuable insights into their structure-activity relationships, paving the way for future advancements in electrocatalysis.