Thermochemical Hydrogen Production Past and Present

International Journal of Hydrogen Energy 26 (2001) 185–190 www.elsevier.com/locate/ijhydene Thermochemical hydrogen production: past and present James E. Funk ∗ Department of Mechanical Engineering, University of Kentucky, 521 CRNS Bldg., Lexington, KY 40506, USA Abstract The processes for hydrogen production discussed in this paper are those for which water is the only material input and hydrogen and oxygen are the only material outputs: H2 O + X → XO + H2 XO → X + 1=2O2 —————————————− H2 O → H2 + 1=2O2 Furthermore, the required energy inputs are meant to be mainly heat (rather than useful