(183k) Laser-Induced Synthesis of Metal Organic Frameworks (MOF): A Facile Approach for the Fabrication a Wide Range of Crystalline MOFs and Their Functional Composites

Ribeiro, E. L. - Presenter, University of Tennessee, Knoxville
Mukherjee, D., University of Tennessee
Khomami, B., University of Tennessee
Metal Organic Frameworks (MOFs) are fast emerging as a new class of crystalline hybrid porous materials. The high permeability of MOFs arising from their nanometric pores and the resulting exceedingly high free volumes and surface areas have attracted tremendous interest in numerous engineering applications for these materials. In recent years, diverse scientific and engineering communities have demonstrated the ability of MOFs to enhance the performance of several processes, including gas storage, fluid separations, sensing, catalysis, luminescence, and photovoltaics. Despite the versatile applications of such materials, facile, rapid yet environmentally friendly fabrication strategies for MOFs that allow precise control on their morphology and structures are still challenging. Herein, we report a facile route using high-energy laser ablation synthesis in solution (LASiS) to produce highly crystalline zeolitic imidazolate framework-67 (ZIF-67) structures by ablating Co targets in 2-methylimidazole (Hmim) solutions. Synthesis protocols presented here demonstrate for the first time the ability of LASiS to rationally tailor the sizes and shapes of MOF structures by adjusting solution-phase (reagent concentration and temperature) and laser (ablation time) parameters. Thereafter, we will present a mechanistic picture for MOF formation via LASiS, providing an understanding that will allow the expansion of LASiS as a strategy and pathway for the synthesis of a wide range of MOF structures. Finally, we will present the potential of LASiS coupled with Galvanic Replacement Reaction (tandem LASiS-GRR) for the first time for the synthesis of catalytic nanoparticles (NPs) confined within two different structures: ZIF-8 and ZIF-67. We show that the advantage of such nanocomposite structures is in its ability to achieve well-dispersed and spatially confined NPs after calcination treatments on suitable substrates that hinders NP aggregations during catalytic activities. To this end, preliminary results for post-calcined Pt/MOF composites have also shown promising catalytic activities towards Oxygen Reduction (ORR) and Oxygen Evolution Reactions (OER).