Exceptional performance of water splitting coupled with methane partial oxidation by oxygen-permeable membrane reactor

Abstract

An oxygen-permeable membrane reactor, capable of high-performance water splitting and simultaneous methane conversion while maintaining the syngas ratio (H-2/CO) close to 2, is reported in this study. Most coupling studies of water splitting and partial oxidation of methane (POM) using oxygen-conducting ceramic membranes have so far focused on the application in high-temperature (>900 degrees C) conditions that can accelerate the kinetics of surface exchange reactions. Considerable hydrogen production through the coupling reaction is possible below 800 degrees C by adopting Ruddlesden-Popper oxide for water reduction and a Ni/perovskite/fluorite composite for POM. The membrane composition was optimized to maximize the oxygen ionic conductivity and ensure the stability. Using a chemically stable dual-phase membrane with highly active coating layers, the production of 4.5 mL center dot cm(-2)center dot min(-1) of hydrogen from water splitting and 14 mL center dot cm(-2)center dot mi(-1) of syngas from methane were stably secured at 800 degrees C. In addition, coupling reaction was confirmed to be possible even at 700 degrees C.