A series of mixed-metal (cobalt and iron) Metal-Organic Frameworks (MOFs)were synthesized by the direct reaction of 2-aminoterephthalic (NH2-BDC) with stoichiometric amounts of cobalt and iron salts. So obtained MOFs designated as CoxFe1-xBDC-NH2(where x = 0.2 to 1 with 0.2 increment) showed a MIL-88B structure and crystallanity of MOFs decreased with increasing cobalt content as characterized with X-ray Powder Diffraction (PXRD) analysis. Also a change in the morphology of MOF crystals from octahedral in pristine MOF to spindles (mixed metal Fe/Co MOF) to rod-like in MOF with Co only was observed with Scanning Electron Micrscopy (SEM). Energy Dispersive X-ray (EDX) analysis confirmed the presence of both cobalt and iron within the MOF crystals. The catalytic performance of the materials was tested for nitroarenes reduction at room temperature. Fe to Co ratio in MOFs had strong impact on the activity and selectivity of the hydrogenation products. We have also investigated the potential of our MOF-catalysts for Oxygen Evolution Reaction (OER). MOF with equimolar amount of Fe and Co showed the best OER activity providing benchmark current density (10 mA.cm-2) at overpotential of just 420 mV, which is comparable to the benchmark OER catalyst (RuO2). This catalyst also showed long-run stability in 1M KOH. In a third catalytic test, dehydrogenation of sodium borohydride was test and high activity (TOF: 157/min) and hydrogen generation rate (121L/min/g catalyst) was obtained. This study shows the potential of mixed metal MOFs for various catalytic applications.

Mixed-metal metal–organic frameworks as multifunctional catalysts

2019 Fall National Meeting

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