2D iron/cobalt metal–organic frameworks with an extended ligand for efficient oxygen evolution reaction

Abstract

The design of an efficient OER catalyst is significant for water splitting. Metal–organic frameworks (MOFs) are emerging as promising electrocatalysts due to their diversity of structure and tunability of function. In this paper, 2D Fe_xCo_1−x-MOF₁/NF with an extended ligand (biphenyl-4,4′-dicarboxylic acid, BPDC) is constructed on nickel foam by a solvothermal method. Compared with the MOF₂ synthesized by using BDC (1,4-bezenedicarboxylate), MOF₁ shows excellent performance. Among MOF₁, Fe_0.5Co_0.5-MOF₁/NF exhibits outstanding performance with a low overpotential (217 mV) and a small Tafel slope (31.16 mV Dec⁻¹) at 10 mA cm⁻² and performs well at a high current density. In addition, the catalyst is remarkable in terms of durability both in alkaline solution and simulated seawater. The synergetic effect between Fe and Co and more active sites exposed play an important role in improving the OER activity. This work provides an effective strategy for the rational design of MOFs as inexpensive electrocatalysts.