Improving the mechanical strength and gas separation performance of CMS membranes by simply sintering treatment of α-Al2O3 support

•Optimizing the support for CMSM to enhance mechanical strength and performance.•The physical properties of support was modified by different sintering conditions.•Support with smaller pore size and rougher surface is benefits for CMSM.•The tetradecahedral shape of support sintered at 1400 °C was suitable for CMSM.

Asymmetrical thin carbon molecular sieving (CMS) membranes exhibiting good mechanical strength and high separation performance were prepared by changing the physical properties of α-Al2O3 substrates. The physical properties of the substrates, such as pore size, pore volume and surface roughness, significantly influence the penetrability of polymer solution and were systematically modified by sintering temperature, heating rate and dwell time. The tetradecahedral shape of the substrate achieved at the sintering temperature of 1400 °C was found to be suitable for the prepared CMS membranes, which exhibited a H2 permeability of 1300 Barrer with H2/CH4 and CO2/CH4 selectivities of 174.16 and 56.44, respectively. To optimize the substrate structure to provide a cost-effective and highly productive method for the deposition of brittle CMS membranes, this proposed procedure can be used to improve the mechanical strength of the supported membrane for enhanced manipulation.