Tailoring Active Sites in Amorphous NiFe-MOFs through Pyridine Ligand Coordination for Enhanced Oxygen Evolution...

The development of high-performance, cost-effective non-noble metal catalysts for the oxygen evolution reaction (OER) is critical to advancing sustainable hydrogen production via water electrolysis. Herein, we report a facile and mild strategy for synthesizing amorphous bimetallic organic framework materials (NiFe-MOFs) using pyridine-modified threonine (l-PyThr) as an organic ligand. The optimized NiFe-PyThr-4:1 catalyst exhibits remarkable OER activity, requiring low overpotentials of only 162 and 222 mV to achieve current densities of 10 and 100 mA cm^-2, respectively, along with a small Tafel slope of 34.1 mV dec^-1. Compared to monometallic Ni-PyThr and unmodified NiFe-Thr-4:1 controls, NiFe-PyThr-4:1 shows significantly enhanced electrocatalytic activity and long-term stability. Density Functional Theory (DFT) calculations reveal that Fe serves as the principal active site, while the l-PyThr ligand modulates the electronic structure and adsorption behavior of key intermediates, effectively lowering the energy barrier of the rate-determining step. This performance enhancement arises from the synergistic effect of Fe doping and pyridine coordination, which increases the accessible active site density and promotes charge transfer. This work offers mechanistic insights into the structure-function relationship in amorphous MOFs and presents a scalable, low-temperature synthesis route for the rational design of efficient electrocatalysts toward practical water-splitting applications.