Functionalized SBA-15-based catalysts for energy-efficient CO2 desorption: Bridging experimentation and machine learning to enhance amine sorbents regeneration

Improving the energy efficiency of CO2 desorption remains a key challenge in post-combustion carbon capture using amine solvents. In this work, a series of solid acid catalysts based on sulfonated mesoporous SBA-15 and functionalized with phosphotungstic acid (HPW) were synthesized via post-synthetic modification and applied to the catalytic regeneration of monoethanolamine (MEA). The catalysts, featuring both Brønsted and Lewis acid sites, were thoroughly characterized and tested in desorption experiments using CO2-loaded MEA solutions. Among the synthesized materials, HPW-SBA-15-SO3H-1 exhibited the best performance, achieving significantly higher CO2 desorption rate and cyclic capacity compared to the uncatalyzed system, while reducing the relative heat duty by up to 37.7 %. This catalyst also demonstrated good stability over 20 absorption–desorption cycles, maintaining its structural integrity. In addition, machine learning was employed to correlate the catalysts' physicochemical features with their desorption performance, highlighting the role of acidity and porosity and supporting the proposed mechanism by which acidic sites promote carbamate decomposition and MEAH+ deprotonation. These findings underscore the potential of functionalized mesoporous silica as efficient solid catalysts for lowering the regeneration energy penalty in MEA-based carbon capture systems.