Barium Titanate as a Highly Stable Oxygen Permeable Membrane Reactor for Hydrogen Production from Thermal Water Splitting

Abstract

Hydrogen production from water splitting by a mixed ionic-electronic conducting membrane is an efficient and promising technology; however, it is severely impeded by the poor reduction tolerance of the existing cobalt- or iron-containing membrane materials. In this work, a novel BaMg0.1Zr0.05Ti0.85O3−δ (BMZ-Ti) perovskite was synthesized by combining citric acid and ethylenediaminetetraacetic acid methods. The new membrane is characterized by its superior chemical stability in a wet H2 atmosphere as well as with environment-responsive mixed conductivity, generating from the mild reduction of Ti4+ at low oxygen partial pressure. Benefiting from these combined properties, the BMZ-Ti membrane showed an oxygen permeation flux larger than 0.3 mL min–1 cm–2 under a H2O/(CH4–CO2) gradient, more than 50 times larger than that under an air/He gradient, which was able to be used for coupling methane reforming with water dissociation to efficiently produce hydrogen with a production rate of 0.8 mL min–1 cm–2. Furthermore, no performance degradation was observed during an over 100 h test. These results highlight the potential of the BMZ-Ti membrane, with both environment-responsive mixed conductivity and excellent chemical stability, as a novel oxygen permeable membrane for hydrogen production from water.

A review of water splitting via mixed ionic–electronic conducting (MIEC) membrane reactors

“…63 Further research with the BMZ-Ti perovskite also demonstrated excellent chemical stability under a wet H 2 atmosphere, as well as environment-responsive mixed conductivity generated by mild reduction of Ti 4+ at low oxygen partial pressure. 49 In contrast, the effect of Si doping on PSF was explored, it was found that the performance decreased by 19% during 100 h of operation, while the decrease of PSFSi 0.075 reactor was only 7%, which indicated that Si doping did improve its stability. 50 Some researchers have conducted specialized studies on the stability under different atmospheres.…”

“…The BMZ-Ti porous layer with a Ni catalyst on the methane side could reach a hydrogen production rate of 0.8 mL min −1 cm −2 for a 0.7 mm thick membrane. 49 The current commercial catalysts are generally Ni supported on alumina. Ni-Al 2 O 3 was used to catalyze POM in a hollow fiber BCFZ membrane, and a hydrogen production rate of up to 5 mL cm −2 min −1 could be obtained.…”

Divide to Conquer: On the Use of Distributed Feed Strategies in Oxidative Coupling of Methane

“…Others have shown more interest in understanding oxygen permeation through perovskite materials, concentrating on improving ceramic materials for enhanced oxygen flux, chemical stability, and mechanical integrity. Eventually, in addition to OCM, MIEC membranes have found their way in many of oxidation reactions, such as partial oxidation of methane, − C 2 and C 3 reactions (ethane/propane oxidative dehydrogenation to ethylene/propylene), − coal gasification − in addition to other applications such as oxygen production from air, CO 2 reduction, , and H 2 production by water splitting. ,− …”