Enhanced CO₂ Resistance for Robust Oxygen Separation Through Tantalum‐doped Perovskite Membranes

Abstract

Oxygen selective membranes with enhanced oxygen permeability and CO2 resistance are highly required in sustainable clean energy generation technologies. Here, we present novel, cobalt-free, SrFe1-x Tax O3-δ (x=0, 0.025, 0.05, 0.1, 0.2) perovskite membranes. Ta-doping induced lattice structure progression from orthorhombic (x=0) to cubic (x=0.05). SrFe0.95 Ta0.05 O3-δ (SFT0.05) showed the highest oxygen flux rates reaching 0.85 mL min(-1) cm(-2) at 950 °C on a 1.0 mm-thick membrane. Surface decoration can increase the permeation rate further. Ta inclusion within the perovskite lattice of SrFeO3-δ (SF) enhanced the CO2 resistance of the membranes significantly as evidenced by the absence of the carbonate functional groups on the FTIR spectrum when exposed to CO2 atmosphere at 850 °C. The CO2 resistance of Ta-doped SF compounds correlates with the lower basicity and the higher binding energy for the lattice oxygen. SFT0.05 demonstrated high stability during long-term permeation tests under 10% CO2 atmosphere.

Perovskite materials in energy storage and conversion

“…The development of cobalt‐free perovskite membranes with intrinsically high stability has been pursued intensively. In considering the higher chemical stability of iron ions relative to cobalt ions, many iron‐based perovskite oxides have been developed as materials for ceramic oxygen‐permeating membranes, for applications in membrane reactors . For example, a Ba 0.5 Sr 0.5 Zn 0.2 Fe 0.8 O 3 − δ (BSZF) perovskite oxide was reported by Wang et al as a new cobalt‐free perovskite material for use in oxygen‐permeating membranes .…”

Highly Stable Dual‐Phase Membrane Based on Ce0.9Gd0.1O2–δ—La2NiO4+δ for Oxygen Permeation under Pure CO2 Atmosphere

“…As 40 wt% is the minimum percentage to establish the continuous phase for charge conduction, it is reasonable to infer that the GDC‐LNO interface would be further developed crossing the bulk as “inter‐path.” Such enlargement in hetero‐interface areas would finally manifest into a higher oxygen permeation performance via the improved bulk electron and ionic conduction of this dual‐phase membrane . Moreover, the potential Gd‐doping would improve CO 2 resistance of LNO oxide, as gadolinium oxide has lower basicity relative to lanthanum oxide …”

“…Moreover, the MIEC membranes have gained increasing attention because of their potential applications not only for pure oxygen supply to power stations for CO 2 capture but also as membrane reactors for greener chemical synthesis. However, these advanced applications involve the presence of CO 2 at high temperatures, which requires the MIEC membranes to possess sufficient stability against CO 2 resistance . The state‐of‐the‐art MIEC perovskite membranes are limited by the trade‐off phenomenon between the stability and oxygen flux .…”

Lead and tungsten double stabilizing cobalt‐based perovskite oxygen permeation membranes for clean energy delivery

“…As an alternative, it is reasonable to place more faith in clean energy delivery technology, which aims to use fossil fuels in high energy efficiency and zero waste emission way. To address this concern, ionic conducting membranes (ICM) come into the games as they have excellent oxygen permeability and compatibility with power generation applications . Because of the promising options to be integrated with oxyfuel combustion, the ICM offer the potential to improve zero‐emission technology.…”