Thomas Edison used platinum in an early attempt to improve electric lamp filaments.
Platinum has a very high melting point, making it an attractive candidate for a glowing filament. Edison experimented with platinum and other materials while seeking a lamp that could burn reliably, produce useful light, and be manufactured at a practical cost.
Platinum was ultimately too expensive for broad commercial use. Edison’s successful lamp development depended on carbonized materials and careful control of the lamp’s vacuum and electrical resistance. The eventual system involved not just a filament but also sockets, wiring, generators, and distribution equipment.
A common mix-up is to treat every filament material Edison tested as his final commercial choice. Platinum belonged to the experimental stage rather than the durable mass-market solution.