Synergistic Effect of MIL-101/Reduced Graphene Oxide Nanocomposites on High-Pressure Ammonia Uptake

Cheongwon Bae; Gyuyeong Jeong; Suhyeon Park; Yeram Kim; Mingyu Gu; Duckjong Kim; Juyeong Kim

doi:10.1021/acsomega.2c00741

Synergistic Effect of MIL-101/Reduced Graphene Oxide Nanocomposites on High-Pressure Ammonia Uptake

ACS Omega. 2022 May 12;7(20):17144-17150. doi: 10.1021/acsomega.2c00741. eCollection 2022 May 24.

Authors

Cheongwon Bae¹, Gyuyeong Jeong², Suhyeon Park¹, Yeram Kim¹, Mingyu Gu¹, Duckjong Kim², Juyeong Kim¹

Affiliations

¹ Department of Chemistry and Research Institute of Natural Sciences, Gyeongsang National University, Jinju 52828, South Korea.
² Department of Mechanical Engineering, Gyeongsang National University, Jinju 52828, South Korea.

Abstract

Ammonia has emerged as a potential working fluid in adsorption heat pumps (AHPs) for clean energy conversion. It would be necessary to develop an efficient adsorbent with high-density ammonia uptake under high gas pressures in the low-temperature range for waste heat. Herein, a porous nanocomposite with MIL-101(Cr)-NH₂ (MIL-A) and reduced graphene oxide (rGO) was developed to enhance the ammonia adsorption capacity over high ammonia pressures (3-5 bar) and low working temperatures (20-40 °C). A one-pot hydrothermal reaction could form a two-dimensional sheet-like nanocomposite where MIL-A nanoparticles were well deposited on the surface of rGO. The MIL-A nanoparticles were shown to grow on the rGO surface through chemical bonding between chromium metal centers in MIL-A and oxygen species in rGO. We demonstrated that the nanocomposite with 2% GO showed higher ammonia uptake capacity at 5 bar compared with pure MIL-A and rGO. Our strategy to incorporate rGO with MIL-A nanoparticles would further be generalizable to other metal-organic frameworks for improving the ammonia adsorption capacity in AHPs.