The electrochemical behavior of a Metal-Organic Framework modified gold electrode for methanol oxidation

Direct Methanol Fuel Cells have received great interest for portable applications and electric vehicles. Even if the development of new catalysts for fuel cell is always under consideration, the platinum-based ones remain the most used for these technologies. Metal-organic-frameworks (MOF) are noble-metal-free promising materials for fuel cell industry. Although HKUST-1 is not a very stable MOF in aqueous solutions, we prove that the growth from its mother solution over different linkers (mercaptoacetic and trimesic acids) lead to durable HKUST modified electrodes: Au_MAA_HKUST and Au_TA_HKUST. Self-assembling or electrochemical procedures are used to prepare the adlayers on gold electrode. Electrochemical experiments show that the current density obtained for the Au_MAA_HKUST is almost 28 times higher than that of bulk gold electrode. The Au_TA_HKUST electrode reveals a similar response regarding the potential range, but the current densities are lower. The possibility to form the trimesic acid (a component of HKUST-1) adlayer on gold electrode offers us the opportunity to investigate the mechanism of methanol oxidation on HKUST-1 regarding both the organic linker and metallic ions. It is worth noting that the role of trimesic acid in methanol oxidation is low comparing the CuII nodes from HKUST-1.