Low-cost stainless-steel mesh supports enabling high-permeance membranes for high-temperature gas separation

Membrane-based gas separations at elevated temperatures (e.g., 300 °C) are limited by the availability of porous supports that combine thermal robustness, mechanical integrity, and low cost. Conventional ceramic supports suffer from brittleness and sealing challenges, while powder-derived sintered porous stainless-steel (SS) supports, although mechanically robust, are expensive and increase the capital cost of the membrane process. Here, we report a low-cost SS wire-mesh support that, through a novel pore-shrinkage protocol, is transformed into a distinct porous morphology comprising isolated micron-scale openings embedded within a smooth metallic surface. This morphology enables the formation of a nanostructured interlayer by deposition of multiwalled carbon nanotubes (MWCNTs), reducing the effective pore size to <100 nm while maintaining high gas permeance (>10 5 GPU) and thermal stability up to 400 °C. The resulting MWCNT/SS support enables the direct fabrication of ∼1 μm-thick zeolitic imidazolate framework (ZIF-8) membranes, which exhibit permselective H 2 transport at 300 °C, among the highest reported values for thermally robust ZIF-8 membranes. Additionally, the membrane demonstrates stable operation under elevated-temperature ammonia exposure (up to 250 °C). Overall, this work introduces a low-cost metallic support architecture enabled by polishing-induced morphology transformation for high-temperature and aggressive gas separations.