ONE POT SYNTHESIS OF MULTIPLE-PORPHYRIN/GRAPHENE MOFs FOR THE OXYGEN REDUCTION REACTION
2Chemical Engineering Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
3Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel
In the pursuing of low cost, non-precious-metal catalysts for effective Oxygen Reduction Reaction (ORR), a lot of research focused lately on graphene and its derivatives as promising catalysts. On the other hand, the activity of carbon-supported transition metal porphyrins is well known for decades, yet, their low activity and stability towards ORR are not sufficient for usage in fuel cells. Therefore, the incorporation of metallo-porphyrins into a graphene functionalized electrode might result in a metal-organic-framework (MOF) that could combine the advantages of both catalysts.
In the current work we present a simple one step strategy to prepare graphene/metallo-porphyrin catalysts on an electrode surface based on the direct electrochemical reduction of graphene-oxide (GO) in the presence of a metalloporphyrin in the solution.
It is known that metalloporphyrins tend to reduce oxygen by a 2 electron reduction process to H2O2. It was reported that porphyrin dimers could catalyze a 4 electron reduction of oxygen through a co-facial attachment to the O2 molecule1. Therefore we used the described method to encage M-P+/M-P- dimer couples in the reduced-graphene oxide layer. In the case of FeTMPyP/CoTPPS/r-GO MOF, the resulted catalyst have shown a reduction onset at 0.33V in comparison to 0.23V for CoTPPS/r-GO and 0.05V for FeTMPyP/r-GO in 0.1M H2SO4 solutions (all potentials vs. Ag/AgCl reference electrode). Detailed results will be presented.
- J. Olaya et al., J. Am. Chem. Soc., 2012, 134 (1), pp 498–506.
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