NaBr-Impregnated Graphene Aerogel for Ammonia-Based Adsorption Heat Pump Application

Abstract

Ammonia-based adsorption heat pumps (AAHPs) are receivingsignificantattention due to effective low-grade thermal energy usability, cost-effectiveness,and eco-friendliness. For AAHPs to be widely utilized, it is essentialto develop adsorbent materials that meet all of the characteristicsrequired by AAHPs, which has been very challenging. Although metalhalides (MHs) have excellent ammonia adsorption performance, theirpractical application to AAHPs has been limited due to their conformationalinstability during the ammonia adsorption-desorption process.Here, the MH-impregnated graphene aerogel (GA-NaBr) is studied fromthe perspective of AAHPs. Due to the pore structure formed by strongand flexible graphene networks and the high NH3 affinityof the scaffolded NaBr, the composite addressed the MHs' issues,showing much-improved adsorption rate and stability compared to pureNaBr, while maintaining equivalent adsorption capacity. With its structuralstability and impressive adsorption performance, GA-NaBr could bea breakthrough adsorption structure in the field of AAHPs.