Single-step hydrogen production from NH3, CH4, and biogas in stacked proton ceramic reactors

An alternative to directly transporting hydrogen produced at large scales through steam reforming for applications such as vehicular fueling is smaller scale, on-site production from methane or carriers such as ammonia. The hydrogen produced must be separated from co-produced carbon dioxide or nitrogen. Proton ceramic electrochemical reactors can extract pure hydrogen from gas mixtures by electrolytically pumping protons across the membrane at 800°C, but as the extraction proceeds, temperature gradients and entropic effects lead to efficiency drops. Clark et al. developed a nickel-based glass-ceramic composite interconnect that allowed for the design of a more complex reactor pathway (see the Perspective by Shih and Haile). Counterflowing streams balanced heat flows and maintained stable operating conditions that enabled 99% efficiency of hydrogen recovery. —PDS