Abstract
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