Tailoring active hydroxyl group on FeZrOx nano-heterojunction for the enhanced low-temperature CO2-rich amine regeneration

Catalytic regeneration is a key approach to solving high energy consumption issues in the amine-based CO₂ absorption method. Previous studies have shown that loaded acid sites (such as SO₄²⁻) are beneficial for promoting low-temperature CO₂-rich amine regeneration, but their weak binding strength to the support results in limited catalyst life. Herein, we proposed an advanced catalyst modification strategy to maintain the active hydroxyl group (Zr–OH–Fe) via actively transferring electrons on the surface of FeZrO_x nano-heterojunction. Combining in situ DRIFTS and DFT calculations, we revealed that the Zr–OH–Fe at the ZrO₂-Fe₂O₃ heterointerfaces exhibit enhanced proton-donating ability, with deprotonation energy reduced from 2.94 to 2.61 eV compared to Zr–OH (which should be called inert hydroxyl group). This improvement favors the rate-determining proton transfer step from RNH₃⁺ to RNHCOO⁻. Surprisingly, it increased the CO₂ desorption rate by 10.5 times and reduced the energy consumption by 43.6% during amine regeneration. This work offers a practical strategy for improving the performance of low-temperature CO₂-rich amine regeneration catalysts, and the low-cost recyclability of amine used in CO₂ capture.