Dense ceramic membranes based on mixed proton-electron conductors (MPEC) have promising applications in H2 production at T > 600 °C from low-quality gas mixtures (e.g. from biomass). These materials incorporate hydrogen into their lattice as charge protonic defects which means that, theoretically, they are 100% selective towards hydrogen separation. Furthermore, the properties of these oxides (i.e. working temperatures, durability) endow membranes that could be directly integrated into industrial processes or used in the so-called catalytic membrane reactors. Recently, BaCe0.65Zr0.20Y0.15O3-? (BCZ20Y15) and Ce0.85M0.15O2-? (M = Y and Gd) dual-phase membranes were explored by our group [1] reaching hydrogen permeability values among the highest ever reported for bulk MPEC membranes. The highest permeation flux was attained for the 50:50 volume ratio BaCe0.65Zr0.20Y0.15O3-? and Ce0.85Gd0.15O2-? membrane, reaching values of 0.27 mL·min-1·cm-2 at 755°C and 2.40 mL·min-1·cm-2 at 1040°C. However, long term stability and degradation mechanisms are critical issues for these systems. The working conditions are really challenging: H2 purification is carried out at high temperatures in harsh reducing environments containing H2O, CO, CO2, and sulphides. In these conditions, undesired phenomena such as structural changes, cation diffusion, mechanical modifications or chemical reactions could occur damaging the membranes transport performances. This work focuses on BCZ20Y15-doped ceria composites for hydrogen separation membranes. The scope of this study is to systematically examine the chemical stability of these materials in order to obtain a better understanding of their capability for practical applications. [1] E. Rebollo, C. Mortalò, S. Escolástico, S.Boldrini, S. Barison, J. M. Serra, and M. Fabrizio, Energy and Environmental science 8, 3675-3686, (2015)
BaCe0.65Zr0.20Y0.15O3-?-doped ceria ceramic composites for hydrogen separation
E Rebollo;M Fabrizio
2017
Abstract
Dense ceramic membranes based on mixed proton-electron conductors (MPEC) have promising applications in H2 production at T > 600 °C from low-quality gas mixtures (e.g. from biomass). These materials incorporate hydrogen into their lattice as charge protonic defects which means that, theoretically, they are 100% selective towards hydrogen separation. Furthermore, the properties of these oxides (i.e. working temperatures, durability) endow membranes that could be directly integrated into industrial processes or used in the so-called catalytic membrane reactors. Recently, BaCe0.65Zr0.20Y0.15O3-? (BCZ20Y15) and Ce0.85M0.15O2-? (M = Y and Gd) dual-phase membranes were explored by our group [1] reaching hydrogen permeability values among the highest ever reported for bulk MPEC membranes. The highest permeation flux was attained for the 50:50 volume ratio BaCe0.65Zr0.20Y0.15O3-? and Ce0.85Gd0.15O2-? membrane, reaching values of 0.27 mL·min-1·cm-2 at 755°C and 2.40 mL·min-1·cm-2 at 1040°C. However, long term stability and degradation mechanisms are critical issues for these systems. The working conditions are really challenging: H2 purification is carried out at high temperatures in harsh reducing environments containing H2O, CO, CO2, and sulphides. In these conditions, undesired phenomena such as structural changes, cation diffusion, mechanical modifications or chemical reactions could occur damaging the membranes transport performances. This work focuses on BCZ20Y15-doped ceria composites for hydrogen separation membranes. The scope of this study is to systematically examine the chemical stability of these materials in order to obtain a better understanding of their capability for practical applications. [1] E. Rebollo, C. Mortalò, S. Escolástico, S.Boldrini, S. Barison, J. M. Serra, and M. Fabrizio, Energy and Environmental science 8, 3675-3686, (2015)I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
