Effect of substrate pore size and physical gelation on the performance of BTESE-derived silica membranes for gas separation

Hydrogen-selective membranes are pivotal in advancing sustainable energy technologies. Organosilica, due to its hydrothermal stability, has shown promise as a gas separation membrane, but its fabrication requires stringent substrate pore control. This study investigates the influence of substrate pore size and rheological property on bis(triethoxysilyl)ethane (BTESE)-derived membranes. Through sol-gel synthesis modifications, including surfactant-induced gelation, pore filling was reduced while gas selectivity was enhanced on larger-pore substrates (20–50 nm). Rheological analyses confirmed that interparticle force modulation enables shear thickening behavior and results in defect-free membranes with superior hydrogen sieving. These findings expand the scope of BTESE-derived silica membranes for industrial gas separation, highlighting the role of substrate interaction and rheological control in membrane performance. • Substrate pore size effect studied for BTESE-derived silica membranes. • Surfactant, cooling, and shearing induced physical gelation of BTESE colloid. • Physical gelation enabled successful membrane formation on 20 nm pore substrates.