The work focuses on the process development and scale-up of synthesising nanostructured platinum electrocatalysts on carbon-free metal substrates for application in polymer electrolyte fuel cells. A self-limiting electrodeposition strategy was optimised to achieve uniform, low-loading platinum films on silver and gold substrates while mitigating issues such as metal dissolution and surface pitting. Key deposition parameters—including electrolyte composition, pH, pulse conditions, and mass-transport environment—were systematically studied to understand their influence on nucleation, growth, and catalyst stability. A scalable flow-cell reactor was designed and implemented to enable uniform catalyst deposition over large-area substrates, demonstrating repeatability and compatibility with industrially relevant fabrication processes. The resulting carbon-free nanostructured electrocatalysts exhibit improved durability, controlled morphology, and tunable platinum loading, highlighting their potential for next-generation polymer electrolyte fuel cell systems.