Proton-Transfer-Driven Superacid Sites on Etched MCM-22 for Energy-Efficient CO 2 Desorption from Amine Solvents

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The high energy consumption required for regenerating the CO 2 -rich monoethanolamine (MEA) solvent remains a major challenge in industrial CO 2 capture. Herein, we develop a SZMOH catalyst by supporting sulfated zirconia (SO 4 2– /ZrO 2 ) on alkali-etched MCM-22 zeolite, synergizing enhanced acidity and improved mass transfer. Alkaline etching creates silicon vacancies that anchor zirconium species, forming stable superacidic character sites ≡Zr–O–SO 3 . This catalyst significantly boosts desorption performance, increasing the CO 2 desorption capacity by 120%, the maximum desorption rate by 385%, and reducing energy consumption by 37%. Through a combined experimental and theoretical investigation, we elucidate a novel desorption mechanism centered on a sustainable proton transfer cycle. In this cycle, strong acid sites facilitate the extraction of a proton from the catalyst by MEACOO – to form MEACOOH, thereby completing MEA regeneration and CO 2 desorption. Concurrently, the deprotonation of MEAH + replenishes the consumed protons on the catalyst, thus driving continuous operation of the overall catalytic cycle. This process lowers the energy barrier of the rate-determining step from 0.91 to 0.42 eV. Our work offers efficient catalyst design and mechanistic insight into proton-mediated desorption for energy-efficient CO 2 capture.