Synergistic Enhancement of Hydrogen Evolution From Seawater Using a ZIF-8 Integrated Polypyrrole Composite Electrocatalyst

Abstract

This study explores the electrocatalytic performance of a new composite material, ZIF-8@PPy/3D-Ni, for hydrogen evolution reaction (HER) in water splitting. We synthesized ZIF-8 using a straightforward electrodeposition method and characterized it with X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, and Raman spectroscopy. The ZIF-8@PPy composite was created by electrodepositing polypyrrole (PPy) on a 3D-Ni substrate, optimizing the PPy concentration, electrodeposition time, and electrodeposition potential. Electrochemical tests showed that the ZIF-8@PPy/3D-Ni electrode had a low overpotential of 173 mV at 100 mA cm⁻². The Tafel slope for the composite was 64.3 mV dec⁻¹, indicating improved kinetics compared to PPy alone (85.5 mV dec⁻¹). Adding ZIF-8 improved the catalytic activity due to its high-surface area and nitrogen groups that helped proton absorption. The electrode's stability was confirmed by chronopotentiometry, showing promise for practical use in sustainable hydrogen production. Overall, this work demonstrates the effectiveness of ZIF-8@PPy as an electrocatalyst for HER, contributing to future renewable energy technologies.