A method for producing hydrogen includes flowing a first gas along a bayonet flow path of a steam methane reformer (SMR) to produce a first product, including flowing the first gas through a foam disposed along the bayonet flow path; providing the first product produced in the SMR to an input of a water gas shift (WGS) reaction channel defined within a reaction tube of a WGS reactor; and flowing a second gas including the first product through the WGS reaction channel to produce a second product. Flowing the second gas includes flowing the second gas across a heat transfer material disposed in the WGS reaction channel to reduce the temperature of the flowing second gas; and flowing the second gas across a WGS catalyst disposed in the reaction channel.