In an attempt at cold fusion in 1969 I filled a glass bulb with hydrogen at slightly above atmospheric pressure with a coil of palladium wire mounted at the centre.
After a few days the palladium wire glowed white hot with a considerable light.
I suggested cold hydrogen fusion may have occurred, but the consensus was that a small amount of oxygen was present and this oxygen was burning in hydrogen on the palladium wire as a catalyst.
Chris.