Mechanistic insights into the hydrogel-supported catalyst for superior oxygen evolution performance

The oxygen evolution reaction (OER) is a crucial process in renewable energy technologies, yet it remains hindered by sluggish reaction kinetics, high overpotentials, and poor electron and ion transfer. This study introduces a novel hydrogel-supported electrocatalyst, HFc-NG@PVA, which combines hydrazinocarbonylferrocene-modified nitrogen-doped graphene (HFc-NG) with polyvinyl alcohol (PVA) to enhance OER performance. HFc-NG@PVA exhibited a low overpotential (η 10 = 310 mV) and a small Tafel slope (49 mV dec −1 ), outperforming conventional carbon-based electrodes and approaching the performance of IrO 2 . Additionally, the hydrogels exhibit excellent mechanical strength, elasticity, and durability, maintaining stable OER performance over 24 h. Mechanistic studies, including density functional theory (DFT) and COMSOL simulation, reveal that the HFc-NG facilitates electron transfer through redox-active HFc, while PVA, a hydrogel, improves ion conduction, hydration, and mechanical support. The integration of HFc-NG into the PVA matrix not only boosts the mechanical and electrochemical properties of the hydrogel but also enhances the stability of the active sites, enabling more efficient OER. The unique hydrogen-bonding network between HFc-NG and PVA further lowers the activation energy for OER, contributing to its superior catalytic efficiency. This work highlights the potential of hydrogel-supported catalysts as promising candidates for efficient, stable, and cost-effective electrocatalysis in energy conversion systems.