Synthesis and characterization of the magnetic supported metal-organic framework catalysts (CuCoBTC@MAC and CuBTC@MAC) for the hydrogen production from sodium borohydride

Highlights: • Magnetic activated carbon (MAC) was applied as an inert substrate with high surface area. • Bimetallic (Cu–Co) and monometallic (Cu) MOFs supported on the MAC were prepared as a catalyst for hydrolysis of NaBH₄. • Stability of the bimetallic MOF was evaluated by ten cycles and only 19% of reduction in performance was observed. • Maximum hydrogen generation rate was calculated to be 7900 ml min⁻¹.gcat⁻¹. In the present work, it is revealed the synthesis of the remarkable magnetic supported monometallic and bimetallic metal organic framework (MOF) catalysts for the release of hydrogen from NaBH₄. Copper and cobalt-copper based MOFs supported on magnetic activated carbon (MAC) were characterized by applying the common tests encompassing FTIR, BET, XRD, XPS, FESEM, TEM and VSM. TEM and FESEM results showed the well dispersed magnetic MOF nanoparticles with size less than 30 nm. The achievements from the XRD and FTIR also illustrated the formation of the magnetite nanoparticles with the agreement magnetic strength which was confirmed by VSM analysis. The performance of the prepared samples (CuBTC@MAC and CuCoBTC@MAC) was evaluated by the hydrolysis of sodium borohydride at the different operating conditions including temperature, NaBH₄ and NaOH content while the other parameters were kept constant. The maximum hydrogen generation was also measured to be 7900 mL min⁻¹.gcat⁻¹ over the bimetallic supported MOF at the ambient temperature (30 °C) with 5 wt % NaOH and NaBH₄. The stability and reusability of the fabricated catalysts were studied in the ten cycles while the bimetallic MOF indicated only 19% reduction at the end of tenth cycle with capability in the industrial applications. A kinetic equation was derived for the study of the hydrogen production mechanism over the bimetallic sample.