Maximizing Oxygen Permeation via Catalytic Functionalization under Oxyfuel Conditions

Abstract

Oxygen transport membranes (OTMs) offer a promising route for high-efficiency, cost-effective oxygen supply in energy and chemical industries, with the potential to significantly reduce CO2 and NOₓ emissions when integrated into oxy-combustion processes. However, conventional OTMs suffer from poor chemical stability in CO2-rich environments, prompting the development of dual-phase membranes that, while more stable, typically exhibit lower oxygen permeation rates. In this study, we address this limitation by enhancing the surface exchange kinetics of porous Fe2NiO4-Ce0.8Tb0.2O2-δ (NFO-CTO) membranes by surface modification with various oxygen oxidation–reduction reaction (OORR) catalysts, including Ce, Pr, Sm, Tb, Co, Nb, Zr, and Al oxides, and Pr-based binary oxides. Comprehensive characterization using electrochemical impedance spectroscopy, oxygen isotopic exchange, and gas permeation measurements revealed a substantial improvement in surface reaction kinetics. Catalyst activation led to a six-fold increase in oxygen flux under standard conditions and up to a 2.5-fold enhancement under harsh environments containing CO2 and SO2 at 850 °C, mimicking oxyfuel combustion conditions. This work demonstrates that rational catalyst selection and integration can overcome fundamental surface limitations in dual-phase membranes, offering a viable strategy to advance oxygen separation technologies for sustainable energy applications.