Enhanced desulfurization performance of copper aerogel-based absorbents

Copper aerogel was employed as a sulfur absorbent to enhance desulfurization performance. The copper aerogel was synthesized using an ethanolic approach and dried by three different drying techniques of freeze drying, organic solvent sublimation drying with tert-butanol, and acetonitrile. The typical interconnecting and porous structure of the aerogel was clearly observed only for the aerogel sample made by freeze-drying. Further desulfurization tests showed that freeze-dried copper aerogel had the highest sulfur capacity (12 mgS/g-sorbent) at a low temperature of 200 °C. This enhancement was driven by two factors. 1) The interconnecting structure of copper aerogel weakens the gas diffusion resistance, which can prevent the gas from flowing the inside of sample thereby reducing the efficiency of absorbent. 2) The partially oxidized structure of Cu₂O is thermodynamically active toward the desulfurization reaction, which was confirmed by density functional theory calculations. Overall, using copper aerogels with an interconnecting structure and Cu₂O composition would be a novel approach to enhance desulfurization performance.