Which one can produce much energy?

Nuclear bomb is a generic name, which refer to bombs that explode by means of nuclear reactions (i.e. reactions occurring in nucleii, in contrast to chemical bombs that invlove only chemical reactions with orbital elctrons).

Nuclear bombs can be divided into fission bombs (or more commonly called atomic bombs) and fusion bombs (hydrogen bombs). The former makes use of fission reactions (splitting of heavy atoms) and the latter uses fusion reaction (combination of light atoms).

The energy released by a nuclear bomb depends on the amount of fissile or fusion material used in making the bomb. A fission bomb (atomic bomb) can releases more energy than a hydrogen bomb if the amount of fissile material in the former is large.