Recent developments in nickel/copper electrodes using polymer ink catalyst and their synergies for hydrogen production

The growing demand for sustainable energy has accelerated the development of efficient hydrogen production technologies, particularly electrochemical water splitting. This review highlights the recent progress in nickel/copper (Ni/Cu) electrode systems enhanced by polymer ink catalysts, focusing on their synergistic effects in improving hydrogen production. Ni/Cu bimetallic electrodes offer a cost-effective and stable alternative to noble metals, in which nickel facilitates water dissociation and oxygen evolution, while copper improves hydrogen desorption and electrical conductivity. Their combined effect optimizes adsorption energies, enhances charge transfer, and boosts catalytic efficiency in both acidic and alkaline media. The role of polymer ink catalysts is emphasized in enabling uniform catalyst distribution, strong adhesion, and controlled nucleation during electroless deposition, leading to improved electrode morphology and performance. Various synthesis strategies, including electrodeposition, hydrothermal methods, and hierarchical nano-structuring, are discussed for enhancing surface area, active sites, and durability. Additionally, advances in doping, hybrid nanostructures, and porous architectures are reviewed for further performance optimization. Despite remaining challenges in scalability and long-term stability, Ni/Cu electrodes integrated with polymer ink catalysts demonstrate significant potential as scalable, low-cost, and high-performance systems for sustainable hydrogen production and future energy applications.