It is well known that facilitated transport membranes (FTMs) containing CO2 carriers have high CO2 permeability and excellent permselectivity of CO2 over other light gases. The major challenge in developing FTMs for practical applications is the formation of a separation layer containing CO2 carriers on a support membrane. In this research, we prepared composite membranes by forming a dense gel layer containing glycine as the CO2 carrier on polysulfone (PSf) and ceramic (alpha-alumina) support membranes. Because of the smaller pore size of the PSf support membrane, the gel layer formed on the PSf membrane was thinner and had higher CO2 permeance than that formed on the alumina membrane. However, the CO2 permeabilities of the FTMs formed on the two support membranes showed different temperature dependences; the FTM formed on PSf membrane had higher CO2 permeability at elevated temperatures of more than ca. 350 K and lower CO2 permeability at low temperatures up to ca. 350 K than the FTM formed on alumina support. The different temperature dependences on the CO2 permeability resulted from the different properties of the gel layer formed on the support membranes. Improvement of the CO2 permeability of FTMs could be enabled by selecting an adequate support membrane. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.