abstract
Rare earth doped oxides have been intensively promoted for the last two decades to embrace the high-performance target of a ceramic-carbonate composite CO2-separation membrane, with countless incidents of exsolution. Unfortunately, information about securing a safe doping limit in the above case is unavailable in the public domain. Herein we provide a first report, where an answer to this question is rigorously attempted. Thus, the study demonstrates a maximum safe level of doping in a Ce1-XGdXO2-delta-LiNaCO3 (80:20 vol%) composite, where X = 0.10, 0.15 or 0.20. The required sets of ceramic matrix powders were prepared using the Pechini method and consolidated at 1500 degrees C, with intermediate powder coarsening. The composite membranes were obtained by impregnating these matrices with LiNaCO3 at 700 degrees C. The impedance measurement illustrated the highest bulk and total conductivity, at 250 degrees C, in composites with 10 mol% and 15 mol% of Gd doping, respectively. CO2-separation followed the trend in total conductivity, with highest flux of 0.14 cm(3) min(-1) cm(-2) at 650 degrees C for 15 mol% Gd. Post-mortem analysis showed the precipitation of Gd and evaporation of the melt with retention of carbon allotropes on the sweep face of the membrane of 20 mol% Gd. In short, this work gives some insight into optimizing rare earth Gd-doping for improved the performance of a composite CO2-separation membrane.
keywords
CARBON-DIOXIDE SEPARATION; DUAL-PHASE MEMBRANE; LATTICE THERMAL-EXPANSION; DOPED-CERIA; ELECTRICAL-CONDUCTIVITY; HYDROGEN-PRODUCTION; CRYSTAL-STRUCTURE; HIGH-TEMPERATURE; ELECTROLYTES; STABILITY
subject category
Materials Science
authors
Jamale, AP; Henriques, G
our authors
Atul Prabhakar Jamale
Junior ResearcherProjects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC). Specific support (AJ) provided by national funds (OE), through FCT, IP, in the scope of the framework contract foreseen in the numbers 4, 5, and 6 of the article 23 of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. GH is thankful for financial assistance through a starting research grant, Verao com ciencia (UID 50011-CICECO).