With the butt end of the blade missing it would be hard to tell what it could be from.
From what I see it is an aluminum blade, right hand rotation. From the length that you give 2.25 m, which is about 7 feet 4 inches. Add the blade butt to the center of rotation would add about another 6 to 8 inches, so the propeller diameter would be about 16 feet or greater. From the shape of the blade it has similar looks to a B-29 propeller blade, based on the diameter, as there are not very many propellers with that diameter. Example the P47 was around 13 feet in diameter.
If it was a blade from a B-29, the width of the blade about 30 inches down from tip of the blade would be between 11 and 12 inches wide, if it was a full diameter blade.