Porous Strontium Chloride Scaffolded by Graphene Networks as Ammonia Carriers
Zhejian Cao, Farid Akhtar
Abstract
Abstract Strontium chloride (SrCl 2 ) as ammonia (NH 3 ) carriers has been widely exploited due to its high ammonia uptake capacity and low energy penalty for ammonia release. However, the dramatic volume swing during absorption–desorption cycles, from SrCl 2 to Sr(NH 3 ) 8 Cl 2 to SrCl 2 , imposes a challenge to structure SrCl 2 for ammonia storage applications. Herein, a novel porous SrCl 2 structure with SrCl 2 loading up to 96 wt%, scaffolded by reduced graphene oxide (rGO) networks is reported. The optimized porous SrCl 2 ‐rGO composite with 80 wt% SrCl 2 loading maintains the macro‐ and micro‐structure accommodating the volume swing during ammonia absorption–desorption cycles without disintegration, whereas structured SrCl 2 pellets disintegrates directly after the first cycle of NH 3 absorption. The structured porous 80 wt% SrCl 2 ‐rGO composite demonstrates rapid absorption–desorption kinetics, 140% faster in absorption and 540% faster in desorption compared with pure SrCl 2 pellet. The enhancement of the surface area and the presence of SrCl 2 particles in the pores of rGO networks result in a robust and stable structure offering rapid ammonia absorption–desorption kinetics while countermining the volume swing by self‐adjusting “breathing.”