Apparatus and methods for the production of hydrogen using a reformer including a housing, a first plate having a first plurality of fin structures and a second plate having a second plurality of fin structures assembled such that the first plurality of fin structures is interleaved with the second plurality of fin structures. At least one inlet port is formed in at least one of the first plate and the second plate, and at least one outlet port is formed in at least one of the first plate and the second plate. The fin structures may be coated with a catalytic material to enhance or stimulate reactions taking place within the apparatus. A heat exchange device may also be integrated into one or both plates of the reformer.