Research progress and materials selection guidelines on mixed conducting perovskite-type ceramic membranes for oxygen production

Abstract

Oxygen production by air separation is of great importance in both environmental and industrial processes as most large scale clean energy technologies require oxygen as feed gas. Currently the conventional cryogenic air separation unit is a major economic impediment to the deployment of these clean energy technologies with carbon capture (i.e. oxy-fuel combustion). Dense ceramic perovskite membranes are envisaged to replace the cryogenics and reduce O 2 production costs by 35% or more; which can significantly cut the energy penalty by 50% when integrated in oxy-fuel power plant for CO 2 capture. This paper reviews the current progress in the development of dense ceramic membranes for oxygen production. The principles, advantages or disadvantages, and the crucial problems of all kinds of membranes are discussed. Materials development, optimisation guidelines and suggestions for future research direction are also included. Some areas already previously reviewed are treated with less attention.

A new CO2-resistant Ruddlesden–Popper oxide with superior oxygen transport: A-site deficient (Pr0.9La0.1)1.9(Ni0.74Cu0.21Ga0.05)O4+δ

“…have been investigated extensively as OTMs over the past two decades. 5,6 The ionic charge carriers created by acceptor-doping are mobile oxygen vacancies. Indeed, high oxygen uxes are measured for materials with high concentrations of oxygen vacancies.…”

Infiltration, Overpotential and Ageing Effects on Cathodes for Solid Oxide Fuel Cells: La0.6Sr0.4Co0.2Fe0.8O3-δversus Ba0.5Sr0.5Co0.8Fe0.2O3-δ

“…3 Their excellent activity for oxygen reduction has been proved widely. [4][5][6][7][8][9][10] Although the structure and electrochemical processes of LSCF and BSCF are quite different, both of them have long-term stability and redox behavior issues to be clarified, in order to be used as cathode materials in commercial devices. Indeed, when used as cathodes in intermediate-temperatures solid oxide fuel cells (IT-SOFCs), they suffer from chemical and structural instability, which causes degradation during operation time.…”

Carbon Dioxide Reforming of Methane using an Isothermal Redox Membrane Reactor

“…[26] Perovskitesc ircumvent changes of the crystalc lass and phase of stoichiometric metal oxide redox materials [2,[8][9][10] and have attracted much attention for fuel cells ando xygen separation due to their tunable oxygen vacancy concentrations and high oxygen vacancy conductivities. [25,31] We employ electronic structure theory to quantify the thermodynamic limitations of LSCF redox membranes and to identify advanced perovskite compositionsf or solar-drivenD RM. Thet hermochemical stability and the reactione nergetics for perovskites are calculated from the scaling relation [10,39] [39] shown with Figure 4D.P lotting the data for perovskites togetherw ith those for binary metal oxides shows,i nF igure 4A,t hat perovskites can reproduce the redox energetics of expensive or toxic materials [15] -such as LaCuO 3 ,a nd CO from CH 4 at about the same rate as CO from CO 2 .C H 4 conversion reaches 17 %, whereas the CO 2 conversion is at maximum 8.0% due to CH 4 decomposition.…”

“…[29,30] Results and Discussion This is based on its superioro xygen conductivitya nd typically high oxygen vacancy concentrations, stability of the nonstoichiometric cubic phase,t he redox activityo fc obalta nd iron, and the relatively low carbonate formation tendency. [2,6,25,31,32] To optimize performance,t he following section providesaguide for the rational design of prospective redox materials using optimized reactiont hermodynamics.O neend open tubular LSCF redox membranes were fabricated using ap hase inversion technique and evaluated for DRM using at ube-in-shell membrane reactor, as described in detail in the Supporting Information.F igure 1A shows the isothermal productionr ates of CO by CO 2 splitting in the membrane cavity at steady-state.F igure 1B shows the equivalent rates for the productiono fC Oa nd H 2 from CH 4 reforming in the reactors hell. Thef ormationo fC Of rom CH 4 is relatively stable over the course of 20 min and, as expected from mass balance, approximately equal to CO formation from CO 2 .P urging the reactor in absence of the redox membrane at these temperatures with CO 2 did not yield CO.T his confirms that CO 2 is reduced into CO at the inner membrane surface and that the abstracted oxygen is transported across the membrane to activate CH 4 at the outer membrane surface,yielding CO and H 2 .…”