Porous Strontium Chloride Scaffolded by Graphene Networks as Ammonia Carriers

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."

Calcium/strontium chloride impregnated zeolite A and X granules as optimized ammonia sorbents

“…AEMHs and zeolites were reported with an excellent cyclic performance of ammonia sorption and desorption. 33,47,49,50 The zeolite crystal structure maintains identical after 10 cycles in Sr_X according to the XRD patterns as shown in Fig. 2, and additional detachment of AEMH material from the composite granules was not observed after the second ammonia sorption–desorption cycle, suggesting Sr_X and Sr_A possess stable structure and cyclic performance of ammonia sorption and desorption after removing the falling AEMHs.…”

“…For the same mass loading, CaCl 2 requires more space to expand, which would result in higher stress in the granules. 15,47…”

“…For the same mass loading, CaCl 2 requires more space to expand, which would result in higher stress in the granules. 15,47 The inuence of the crack formation induced by the expansion on the mechanical performance was investigated by compression test for the granules aer ammonia tests. As listed in Table 2, the crushing load reduced in the impregnated granules.…”

A Mini-Review on NH3 Separation Technologies: Recent Advances and Future Directions

“…To address these issues, many efforts were also devoted to dispersing the metal chlorides in porous supports for NH 3 separation. 90,91 4.2. Metal−Organic Frameworks.…”

3D-Printed Zeolite NaX-Magnesium Chloride Units as Ammonia Carriers

“…Therefore, efficient approaches to eliminate NOx emissions and clean fuels are of desire. Ammonia (NH3) is one of the most common reductants used for NOx abatement in selective catalytic reduction (SCR) systems [3], and it has also been recognized as a high-density hydrogen storage material [4,5]. As one of the most produced base chemicals (approximately 144 million tons globally in 2020) [6], ammonia demonstrates great potential in both environmental and energy-related applications.…”