AcknowledgementThe authors thank Spanish Ministerio de Econom iacute a

AcknowledgementThe authors thank Spanish Ministerio de Economía y Competitividad for their support for the development of this research (Plan Nacional de I+D, ref. CTQ2012-37450-C02-02).
Ceramic membrane; Mixed conducting oxides; Oxygen permeation; Nonstoichiometric perovskite; Tungsten substituted SCF
1. Introduction
Nonstoichiometric oxides with mixed oxygen-electron conductivity (MIEC) attract increasing attention because of the possibility to use them as the materials for solid oxide fuel cell, as well as in catalytic membrane reactors for carrying out different petrochemical processes.