Enhanced hydrogen selectivity of allylhydridopolycarbosilane (AHPCS)-derived silicon carbide membranes via air curing

Hydrogen is a critical element in numerous industrial processes and as a clean energy source. This study investigates Allylhydridopolycarbosilane (AHPCS)-derived membranes as a viable alternative to conventional Silica (Si) membranes for hydrogen separation. The AHPCS membranes were fabricated using a three-step process involving pre-firing at 300 °C in N2, air curing, and pyrolysis at 700 °C in N2. By optimizing the air-curing temperatures, the cross-linking of AHPCS-derived membranes was improved, leading to enhanced hydrogen selectivity. The highest H2 permeance of ∼1 × 10−6 mol/(m2 s Pa), accompanied by H2/N2 selectivity of ∼200 and H2/C3H8 selectivity of 3386, achieved through air curing at 600 °C followed by pyrolysis at 700 °C. AHPCS membranes showcased remarkable selectivity for H2/N2 with low H2 activation energy (3−5 kJ/mol), clearly surpassing silica membranes and demonstrating their superior performance. These findings underscore the potential of AHPCS membranes for gas separation and purification applications, marking a significant stride in membrane science. [Display omitted] •Allylhydridopolycarbosilane (AHPCS) membranes were fabricated.•AHPCS was air-cured (AC) and pyrolyzed (P) at 700 °C.•AC and P were characterized via TG, FTIR, XPS, and BET.•AC 600 °C showed H2 permeance (∼3 × 10−6 mol/(m2 s Pa) and H2/CH4 > 1000.•AC 600 °C followed by P 700 °C increased H2/N2 to 200.