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

Abstract

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.