Materials for Hydrogen Production with Integrated CO2 Capture

Palladium-based membrane reactors and sorption-enhanced water-gas shift are two promising technologies for efficient production of hydrogen with integrated CO2 capture. This paper discusses material issues of the two crucial materials of these technologies: the membrane and the CO2 sorbent. For Pd and Pd-alloy membranes the major issues concern the stability of the membrane and the poisoning of the membrane surface by compound such as sulfur and carbon monoxide. Both issues are addressed by research into novel Pd-alloys. For the potassium-promoted hydrotalcite CO2 sorbents used in sorption-enhanced water gas shift, the main challenges are a high CO2 adsorption capacity, chemical and mechanical stability, and low steam use for sorbent regeneration. Promising results have recently been reported for several of these challenges. For both hydrogen-selective membranes and CO2 sorbents, the interaction of the materials with sulfur is an import issue to enable their use in the production of hydrogen from coal.