Hydrogen uptake performance of nanocomposites derived from Metal-Organic Framework (Cu-BTC) and metal decorated multi-walled carbon nanotubes (Ni@f-MWCNTs or Pd@f-MWCNTs)

Abstract

The storage of hydrogen in solid materials has been investigated extensively in recent years for on-board vehicle applications for hydrogen fuel cell technology. Metal-Organic Frameworks (MOFs) are unique materials with novel porous structures suitable for reversible gas adsorption at low temperatures. Similarly, another porous material, carbon nanomaterial is also equally important in storage of hydrogen at room temperature. The Proposed new nanocomposites composed of metal-organic framework (Cu-BTC/HKUST-1) and metal-decorated multi-walled carbon nanotubes (Ni@f-MWCNTs or Pd@f-MWCNTs) are promising candidates for physisorption of hydrogen at low temperature and low pressures. Hence, Ni or Pd decorated MWCNTs were mixed with Cu-BTC at 95 °C to get the intercalated composite material. It was observed that Cu-BTC/Ni@f-MWCNTs and Cu-BTC/Pd@f-MWCNTs showed 4.68 and 5.31 wt% adsorption of hydrogen at 77 K and 70 bar, respectively. At 298 K and 70 bar pressure, the above two composites adsorbed 1.29 and 1.67 wt% of hydrogen. Enhanced hydrogen uptake of about 250-350% and 20-30% was observed at 298K by the synthesized composites compared to the Cu-BTC and metal decorated MWCNTs, respectively. Similarly, an enhancement of about 50-75% and 85-150% in the hydrogen adsorption capacity was observed at 77K for the composites compared to the pristine materials. The resultant enhanced hydrogen uptake by composites is probably due to the synergic effect between Cu-BTC and metal decorated MWCNTs.