Performance and stability comparison of PVA-based and PTFE-enhanced carbon nanomaterial coated nickel electrodes for HHO generators

This study examines surface modification of nickel (Ni) electrodes with carbon nanomaterials (CNT, reduced graphene oxide, and Vulcan XC-72) combined with polymer binders, polyvinyl alcohol (PVA) and polytetrafluoroethylene (PTFE), to improve performance in oxyhydrogen (HHO) generators. Instead of separate bilayer structures, a homogeneous composite coating blending PVA and PTFE with CNMs was developed and compared to a PVA-only single-layer electrode. Under alkaline conditions, electrochemical performance was evaluated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The homogeneous PVA-PTFE composite electrodes showed balanced catalytic activities for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), along with enhanced durability, thanks to the hydrophobic protection and bubble detachment properties of PTFE integrated within the conductive PVA matrix. Observed electrode failures, such as binder degradation and layer delamination, were reduced by optimizing slurry composition and heat treatment parameters. This work emphasizes the benefit of a well-mixed single-layer electrode combining PVA, PTFE, and CNMs as a scalable, robust, and efficient approach for sustainable hydrogen production. Future work will systematically optimize composite proportions, slurry rheology, and thermal processing to maximize electrochemical performance and long-term stability.