Large-scale synthesis of low-cost bimetallic polyphthalocyanine for highly stable water oxidation

Abstract Although large-scale synthesis of inexpensive and efficient electrocatalysts for oxygen evolution reaction (OER) is critical for industrial water splitting, little attention has been paid to that. Here, FeCo-bimetallic polyphthalocyanine (FeCo-PPc) with ultra-low-cost of less than $0.1 per gram and excellent OER electrocatalytic performance has been prepared in kilogram-scale for the first time. The FeCo-PPc catalyst, around 1/5000th times lower the cost of the commercial IrO2, exhibits 24 times higher turnover frequency (0.417 s−1 at 300 mV) and much lower the overpotential (308 mV at 500 mA cm−2) than that of IrO2 (0.0177 s−1 and 588 mV, respectively). Moreover, the FeCo-PPc catalyst shows outstanding long-term stability under an industrial condition (6 M KOH and 85℃) at the high current densities of 100 mA cm−2 and 500 mA cm−2. The excellent OER activity can be attributed to the electron interaction between Fe and Co and the electronegativity of N atoms, which regulate the electron cloud density of neighboring atoms and form active sites to promote the adsorption of reactants. Our work may guide rational design and large-scale synthesis of electrocatalysts that work well at high current densities in industrial conditions.