Revolutionizing electrocatalysis through surface engineering of Ni-MOFs using tannic acid for enhanced oxygen evolution reaction efficiency

초록

The synthesis of surface-tuned Ni-metal-organic frameworks (MOFs) using tannic acid as a morphology- modifying agent demonstrated remarkable improvements in the electrocatalytic performance during the oxygen evolution reaction (OER). The novelty of this study lies in the use of tannic acid, which played a crucial role in enhancing catalytic activity by altering surface properties, creating surface roughness, and improving the distribution of active sites for the OER process. FE-SEM and TEM analyses showed that tannic acid changed the morphology from nanosheet and rods to ruptured surfaces with reduced particle sizes (similar to 20 nm). While conducting the experiment, the X-ray diffraction confirmed high crystallinity of the materials with well-defined crystalline structures, whereas Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectrometer (XPS) analyses validated the formation of Ni-MOFs and their compositional changes before and after the OER. Moreover, the electrochemical studies highlighted the excellent activity of TA@Ni-MOF-3, further exhibiting the lowest overpotential of 227 mV at 10 mA/cm(2) and superior Tafel slope of 119 mV/dec, which were attributed to the optimized distribution of active sites and enhanced conductivity. Furthermore, stability tests and impedance analyses further confirmed the long-term durability and low charge-transfer resistance of the surface-tuned catalysts. This study highlights the potential of surface modification using tannic acid for improving the catalytic efficiency and stability of MOFs for renewable energy applications.

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