CO₂ Separation Improvement Produced on a Ceramic–Carbonate Dense Membrane Superficially Modified with Au–Pd

Abstract

Ceramic–carbonate membranes have been proposed for the selective separation of CO2. In previous reports, membranes performance has been enhanced through the improvement of microstructural features and conductivity properties. Different to the aforesaid, this paper was focused on modifying the membrane surface by incorporating metallic particles to promote the involved surface reactions. First, a composite made of a Ce0.85Sm0.15O2−δ and Sm0.6Sr0.4Al0.3Fe0.7O3−δ was chemically synthesized. Then porous supports were obtained by pressing powders and sintering. Then, dense membranes were fabricated by infiltration of the supports with molten carbonates and the subsequent deposition of metallic Au–Pd particles on the membrane feed side surface. Obtained membranes were tested for CO2 separation between 700 °C and 900 °C, using different feed gas mixtures. Membranes show excellent CO2 permeance (1.72 × 10–7 mol m–2 s–1 Pa–1) operating at low CO2 partial pressure in the feed side (P CO2 = 0.115 atm), wherein about 24% of the total permeation values resulted from the surface modification approach. The permeation mechanism is discussed on the basis of these results.

Dendritic silver self-assembly in molten-carbonate membranes for efficient carbon dioxide capture

“…[24][25][26][27][28][29][30][31][32][33] More recently, a combination of the two has been explored. [34][35][36] Ceramic-carbonate membranes are most commonly fabricated using ceramics with oxide-ion conductivity. It is proposed in the literature that ceramiccarbonate membranes exploit reversible reaction (1) at the interface between MC, ceramic support and gas phase:…”

Mixed-conducting ceramic-carbonate membranes exhibiting high CO2/O2 permeation flux and stability at high temperatures

“…As mentioned, one of the most attractive properties of fluorite-perovskite composites for the manufacture of membranes is their chemical stability under CO 2 containing atmospheres [23][24][25]37]. This property is a fundamental requirement for its application in membranes for CO 2 separation [16,18,23] and membrane reactors [38].…”

“…Recently, a novel sort of MIECC-based ceramiccarbonate membrane has been reported [23][24][25]. The distinctive feature of this membrane is that ceramic phase is made of a fluorite-perovskite composite exhibiting well separated grains of the two phases; which are an oxygen ionic conductor (Ce 0.85 Sm 0.15 O 2 ) and an ionic-electronic conductor (Sm 0.6 Sr 0.4 Al 0.3 Fe 0.7 O 3 )…”

Enhancing Oxygen Permeation via the Incorporation of Silver Inside Perovskite Oxide Membranes

“…Palladium and platinum have been successfully applied as catalysts to improve O 2 fluxes of perovskite membranes [44,45]. Silver (Ag) is a promising alternative to Pt or Pd-based catalyst due to its affordable price, good oxygen solubility, and compatible catalytic activity to promote the overall oxygen permeation rate [46][47][48]. For example, Tan et al used a brush-painting method to coat the La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ (LSCF) membranes with flux improvement by a factor up to 10 depending on the operating conditions [46].…”