Efficient Ag₂O–Ag₂CO₃ Catalytic Cycle and Its Role in Minimizing the Energy Requirement of Amine Solvent Regeneration for CO₂ Capture

Abstract

The worldwide large-scale deployment of the state-of-the-art CO2 capture technique is being delayed due to the overwhelmingly high energy consumption in the stripper. Here, we reveal an efficient Ag2O–Ag2CO3 catalytic cycle and analyze its activity in the amine solvent regeneration step which is capable of greatly minimizing the energy requirement by desorbing greater amounts of CO2 at up to 1000% higher desorption rate, at low temperature, e.g. 80 °C. After substantially improving the CO2 desorption, the Ag2O converts into Ag2CO3 which is even more efficient. The Ag2CO3 ultimately decomposes into Ag2O in the amine regeneration step, and this cycle continues. The validity of the cyclic catalytic behavior was tested for ten cycles. Furthermore, the mechanism of Ag2O/Ag2CO3 facilitated CO2 desorption was elucidated using 1H and 13C nuclear magnetic resonance spectroscopy.