Successful amino-grafting functionalization of MIL-53(Al) through impulse dielectric barrier discharge plasma for hydrogen storage

The present study investigates the functionalization of a commercial Metal-Organic Framework (MOF) named “MIL-53(Al)” using an NH3 impulse dielectric barrier discharge (IDBD) plasma treatment. The main objective of this research is to assess the efficacy of the IDBD treatment in grafting nitrogenous groups onto the MOF's organic ligand. Additionally, the impact of the plasma functionalization on the hydrogen adsorption capacities of the “MIL-53(Al)” after IDBD treatment is also studied. In order to accomplish these objectives, plasma diagnostics and comprehensive material characterization techniques are utilized. Structural and thermal analysis by HT-XRD and TGA-MS respectively, indicate the excellent thermal and chemical stability of the material against high temperatures and ammonia. Chemical analysis of the materials by XPS shows that the IDBD treatment effectively functionalizes the MIL-53(Al) by substituting a carbon with a nitrogen within the organic ligand. Finally, the analysis of the hydrogen adsorption capacities at 1 bar and 25 °C reveals that the amount of hydrogen stored in the MIL-53(Al) treated by IDBD is significantly higher. Specifically, the amount of hydrogen stored surpassed the untreated MIL-53(Al) by approximately 50%. [Display omitted] •A post-synthetic modification process of MIL-53(Al) by IDBD plasma treatment is proposed and investigated.•NH radicals present in the plasma phase seem to contribute to graft amino groups onto MIL-53(Al) organic ligand.•Successful functionalization by IDBD treatment of MIL-53(Al) by substituting carbon with nitrogen within the organic ligand.•A 50% increase in hydrogen storage capacity for MIL-53(Al) treated by IDBD is obtained.