Permeability and stability enhancement of dual-phase membrane by nickel-based porous layer for water splitting

Abstract

The high oxygen permeability and stability of oxygen transport membrane (OTM) materials remain critical issues in the implementation of hydrogen production via thermochemical water splitting. In this study, a novel design of a fluorite phase Ce0.85Pr0.15O2-δ (CP) porous layer coupled with a nickel-based catalyst anchored to a dual-phase Ce0.85Pr0.15O2-δ-Pr0.6Sr0.4Fe0.9Al0.1O3-δ (CP-PSFA) ceramic membrane is developed owing to its excellent tolerance in the reductive atmosphere during static experiments. The oxygen permeability and hydrogen production performance of the modified CP-PSFA OTM were improved significantly with the coating of the CP porous layer; that is, a high O2 permeation flux of 3.7 mL cm-2 min-1 at 925 °C under a reductive atmosphere was achieved, which was approximately 43% higher than that of its counterpart. Meanwhile, after the nickel-based catalyst was loaded, the hydrogen production rate reached 1.79 mL cm-2 min-1 at 925 °C with the condition of optimal catalyst loading (30 wt% NiO), which shows a 64% increase compared to its counterpart. In addition, the long-term stability of the modified membranes remained intact. The results prove that the CP porous layer loaded with a nickel-based catalyst improves the permeability of the CP-PSFA ceramic membrane as well as the stability, providing an effective strategy for the design of high-performance OTMs for thermochemical water splitting for hydrogen production.