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

Ammonia-based adsorption heat pumps (AAHPs) are receiving significant attention due to effective low-grade thermal energy usability, cost-effectiveness, and eco-friendliness. For AAHPs to be widely utilized, it is essential to develop adsorbent materials that meet all of the characteristics required by AAHPs, which has been very challenging. Although metal halides (MHs) have excellent ammonia adsorption performance, their practical application to AAHPs has been limited due to their conformational instability during the ammonia adsorption–desorption process. Here, the MH-impregnated graphene aerogel (GA-NaBr) is studied from the perspective of AAHPs. Due to the pore structure formed by strong and flexible graphene networks and the high NH3 affinity of the scaffolded NaBr, the composite addressed the MHs’ issues, showing much-improved adsorption rate and stability compared to pure NaBr, while maintaining equivalent adsorption capacity. With its structural stability and impressive adsorption performance, GA-NaBr could be a breakthrough adsorption structure in the field of AAHPs.