Enhancing the electrocatalytic activities of metal organic frameworks for the oxygen evolution reaction with bimetallic groups

Dalton Trans. 2023 Dec 5;52(47):17834-17845. doi: 10.1039/d3dt02979d.

Abstract

Controlling the ratio of metals in bimetallic organic frameworks (MOFs) can not only alter the structures but also tailor the properties of MOFs. Herein, we report a series of electrocatalytically active CoxNiy-based bimetallic MOFs that are synthesized with the 3,5-pyridinedicarboxylic acid (3,5-H2pdc) ligand (where x : y = 20 : 1, 15 : 1, 10 : 1, 5 : 1, 1 : 1, and 1 : 20) and a facile, scalable, low temperature synthetic route. The materials have one-dimensional (1D), rod-like microstructures with different aspect ratios. While they all electrocatalyze the oxygen evolution reaction (OER) in alkaline solution (1 M KOH), their electrocatalytic performances vary substantially depending on their compositions. The CoxNiy-MOF with an optimal ratio of x : y = 15 : 1 (Co15Ni1-MOF) electrocatalyzes the OER with the highest maximum current density (92.2 mA cm-2 at 1.75 V vs. RHE) and the smallest overpotential (384 mV vs. RHE at 10 mA cm-2) in a 1 M KOH solution. It is also stable under constant current application during the electrocatalytic OER. This work demonstrates the application of bimetallic MOFs that are synthesized following a simple, low temperature synthetic route for the OER and their tailorable electrocatalytic properties for the OER by varying the ratio of two metals and the synthetic conditions used to produce them.