Enhanced H2 permeation and CO2 tolerance of self-assembled ceramic-metal-ceramic BZCYYb-Ni-CeO2 hybrid membrane for hydrogen separation

Abstract

Perovskite-type mixed protonic-electronic conducting membranes have attracted attention because of their ability to separate and purify hydrogen from a mixture of gases generated by industrial-scale steam reforming based on an ion diffusion mechanism. Exploring cost-effective membrane materials that can achieve both high H2 permeability and strong CO2-tolerant chemical stability has been a major challenge for industrial applications. Herein, we constructed a triple phase (ceramic–metal–ceramic) membrane composed of a perovskite ceramic phase BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (BZCYYb), Ni metal phase and a fluorite ceramic phase CeO2. Under H2 atmosphere, Ni metal in-situ exsolved from the oxide grains, and decorated the grain surface and boundary, thus the electronic conductivity and hydrogen separation performance can be promoted. The BZCYYbNi-CeO2 hybrid membrane achieved an exceptional hydrogen separation performance of 0.53 mL min−1 cm−2 at 800 °C under a 10 vol% H2 atmosphere, surpassing all other perovskite membranes reported to date. Furthermore, the CeO2 phase incorporated into the BZCYYb-Ni effectively improved the CO2-tolerant chemical stability. The BZCYYbNi-CeO2 membrane exhibited outstanding long-term stability for at least 80 h at 700 °C under 10 vol% CO2–10 vol% H2. The success of hybrid membrane construction creates a new direction for simultaneously improving their hydrogen separation performance and CO2 resistance stability.