Membrane reactors for producing hydrogen are devices coupling a membrane and a cata lyst bed they perform simultaneously both the reaction and the hydrogen separation In this way reaction conversions beyond the thermodynamic values can be attained (shift effect) In particular Pd based dense membranes are capable to separate selectively the hydrogen from other gases Their use into membrane reactors which carry out dehydro genation reactions permits producing ultra pure hydrogen This review considers the techniques of manufacturing Pd based membranes the design of membrane reactor modules and the processes for producing pure hydrogen via reforming of hydrocarbons and alcohols Mainly, the work carried out at ENEA Frascati laboratories and a comparative description of other relevant technologies are considered in this paper (C) 2010 Professor T Nejat Veziroglu Published by Elsevier Ltd All rights reserved