Oxygen permeation properties and surface modification of acceptor-doped CeO2/MnFe2O4 composites

Abstract

The preparation and oxygen permeation properties of the (Ce 0.8 Pr 0.2 )O 2−δ − x vol% MnFe 2 O 4 composites, where x = 0 to 35, have been investigated. The samples were prepared by the Pechini method. In the case of Ce 0.8 Pr 0.2 O 2−δ , an oxygen flux density of 6 μmol·cm −2 ·s −1 (L = 0.0247 cm) and the maximum methane conversion of 50% were attained at 1000 • C. Unlike composites consisting of Gd-doped CeO 2 and MnFe 2 O 4 , the oxygen permeability of the (Ce 0.8 Pr 0.2 )O 2−δ -x vol% MnFe 2 O 4 composites was almost constant regardless of the volume fraction of MnFe 2 O 4 ; however, the optimum volume fraction of MnFe 2 O 4 was determined to be 5 to 25 in the context of the chemical and mechanical stabilities under methane conversion atmosphere. In addition, the surface modification of the (Ce 0.8 Gd 0.2 )O 2−δ -15 vol% MnFe 2 O 4 composite was performed by using the FePt nanoparticles. The catalyst loading of 2.8 mg/cm 2 on the both side of the 0.3 mm-thick (Ce 0.8 Gd 0.2 )O 2−δ -15vol% MnFe 2 O 4 composite increased the oxygen flux density from 0.30 to 0.76 μmol·cm −2 ·s −1 in the case of He/air gradients; however, the effect seems to be reduced in the case of high oxygen flux density caused by a large pO 2 gradient. Moreover, the Langmuir-Blodgett film of the FePt nanoparticles were successfully prepared on the tape-cast (Ce 0.8 Gd 0.2 )O 2−δ -15vol% MnFe 2 O 4 composite. Hydrophobic treatments for the surface of the composite were crucial to achieve high transfer ratio for the deposition of the LB film.

Oxygen permeation modeling for Zr0.84Y0.16O1.92–La0.8Sr0.2Cr0.5Fe0.5O3− asymmetric membrane made by phase-inversion

“…Another type is composite materials which involve an oxygen ionic conducting phase and an electronic conducting phase. These dual-phase composites show improved stabilities, but their oxygen permeability is significantly lower than the single-phase materials [7][8][9][10][11][12]. However, this low permeability can be improved by fabricating the dual-phase composites into asymmetric structure [13,14], especially made by phase-inversion [15][16][17][18][19][20][21][22].…”

Effect of ZnO on Structural and Magnetic Properties of MnFe2O4/ZnO Nanocomposite

“…Therefore, various studies on Mn-Ferrite nanoparticles properties have been reported in literature [8][9][10][11][12][13][14][15][16]. However there are few reports on MnFe 2 O 4 /metal oxide composite systems [17,18] It this study, MnFe 2 O 4 /ZnO nanocomposite was prepared using a simple method, and the structural and magnetic properties of composite were compared with MnFe 2 O 4 nanoparticles through different characterizations.…”

Preparation of Integrated Oxygen Permeable Membranes with a Porous Layer by Partial Reduction Process

“…4,5) In addition to those single-phase-type materials, dual-phase-type membranes such as (Ce 0:85 Sm 0:15 )O 2À -15 vol%MnFe 2 O 4 showing high oxygen flux density and good chemical stability have been reported. [5][6][7][8][9][10] To further improve the oxygen flux density, the preparation of integrated oxygen permeable membrane where a thinner membrane is supported on a mechanically tough porous substrate appears to be effective. 11) Oxygen permeable membranes also suffer from degradation due to use under oxygen partial pressure gradient, 5pO 2 , across the membrane as shown in Fig.…”