Unprecedented CO2-Promoted Hydrogen Permeation in Ni-BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ) Membrane

摘要

Conventional Ni-BaCeO3-based membranes possess high hydrogen permeation flux but suffer serious flux degradation in CO2-containing atmosphere because of the formation of BaCO3 insulating layer. In this work, we report a novel Ni-BaZr_(0.1)Ce_(0.7)Y_(0.1)Yb_(0.1)O_(3-δ) (Ni-BZCYYb) membrane, capable of both high hydrogen permeation flux and stable performance in CO2-containing atmosphere at 900 °C Most importantly, the flux is found to be promoted rather than being diminished by CO2 normally observed for other high temperature proton conductors. The flux enhancement in Ni-BZCYYb membrane is attributed to the increase of moisture content in feed gas. When CO2 is introduced, the reverse water-gas shift reaction takes place generating H2O and CO. This work demonstrates that CO2 can be beneficial rather than detrimental for hydrogen permeation membranes that possess high chemical stability.