One-step synthesis of SO42−/ZrO2‑SEP solid-acid catalyst for energy-efficient CO2 capture

The application of solid-acid catalysts in the regeneration process of CO₂-rich amine solutions is currently considered as a promising method for reducing the relative heat duty of CO₂ capture processes. In this study, sepiolite (SEP) was selected as a cost-efficient catalyst carrier to support the solid superacid SO₄^2-/ZrO₂ (SZ) for preparing a series of composite SO₄²⁻/ZrO₂‑SEP (SZ@SEP) catalysts with different SZ/SEP ratios. The physical–chemical properties of the prepared catalysts were carefully studied using various characterization techniques. The catalytic CO₂ desorption performance was tested in the conventional 5 M MEA solution at 88 °C. The amount of desorbed CO₂, desorption rate and relative heat duty were accurately measured for each catalyst and a potential catalytic reaction mechanism was proposed. The results indicated that all catalysts significantly enhanced CO₂ desorption performance. Specifically, SZ@SEP-1/2 achieved a 37.3 % increase in average desorption rate and a 48.6 % decrease in heat duty compared to the blank solvent. Furthermore, SZ@SEP-1/2 demonstrated excellent stability over 20 cycles, suggesting its potential as an energy-efficient catalyst for CO₂ capture.