Construction of Three-Dimensional Hierarchical Pine-Needle-Like Ce–Ni Metal–Organic Frameworks for High-Efficiency Electrocatalytic Oxygen Evolution

The design of high-efficiency, durable electrocatalysts derived from earth-abundant metals is crucial for achieving cost-effective hydrogen generation through water electrolysis. This work presents a bimetallic CeNi-metal-organic-framework (MOF) synthesized using a dual-ligand strategy with 1,3,5-benzenetricarboxylic acid and 2-aminoterephthalic acid and grown in situ on Fe foam. The material exhibits a unique three-dimensional pine-needle-like morphology. As an electrocatalyst for the oxygen evolution reaction (OER) in alkaline electrolyte, the CeNi-MOF shows superior activity compared to its single-metal analogues, requiring an overpotential of 244 mV to reach 10 mA·cm-2, with a Tafel slope of 53.03 mV·dec-1. It also demonstrates stable operation for 100 h at a high current density of 100 mA·cm-2. The observed enhancement originates from the synergistic interaction between Ce and Ni, which promotes electron transfer and increases the proportion of active Ni3+ and Ce4+ species. This synergy is further evidenced by a reduced charge-transfer resistance, an increased electrochemical surface area, and optimized adsorption of reaction intermediates. The results highlight the effectiveness of combined bimetallic and dual-ligand design supported on a conductive substrate in MOF-based electrocatalysts for improved OER performance.