Enhanced H2 production by using La5.5WO11.25-δ-La0.8Sr0.2FeO3-δ mixed oxygen ion-proton-electron triple-conducting membrane

Although lanthanum tungstates (Ln(n)WO(12)(-delta)) show superior CO2-tolerance compared to the traditional perovskite-type oxides, their hydrogen permeation fluxes are not competitive. Herein, a mixed oxygen ion-proton-electron triple-conducting membrane with a nominal composition of La5.5WO11.25-delta-La0.8Sr0.2FeO3-delta (LWO-LSF) was developed for H-2 production. The triple-conducting membrane is composed of a LWO phase with proton conductivity and a LSF phase with mixed oxygen ion-electron conductivities. In the LWO-LSF membrane, proton (H+) permeation and oxygen ion (O2-) counter-permeation property was simultaneously displayed. The improved H-2 production can be ascribed to (1) hydrogen permeated as H+ through LWO phase, and (2) hydrogen produced from water splitting that is enhanced by O2- counter-permeation through LSF phase. A higher H-2 flux of 0.15 mL min(-1) cm(-2) was achieved at 900 degrees C using LWO-LSF triple-conducting membrane, compared with the conventional proton-electron conducting membranes LWO or La5.5WO11.25-delta-La0.8Sr0.2CrO3-delta (LWO-LSC). Furthermore, the constant H-2 fluxes in various atmospheres indicated the good stability of LWO-LSF membrane in simulated raw hydrogen. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

By developing a mixed oxygen ion-proton-electron triple-conducting membrane LWO-LSF, a high H-2 flux in H-2 production was achieved by enhancing H-2 production efficiency through the permeation and counter-permeation of proton and oxygen ion.