Fuel cells are promising alternative energy conversion devices. Their high energy density and efficiency in addition to the consumption of environmentally-friendly fuels such as hydrogen, drew a lot of attention in recent years. However, there are still some challenges to overcome. The most common cathode catalyst used to expedite the oxygen reduction reaction is platinum, which is relatively scarce and expensive. Many attempts to replace the platinum with precious group metal-free (PGM-free) catalysts were made, most of them are metal-nitrogen complexes in which iron and cobalt exhibit the best activity. One of the most prominent PGM-free catalyst family now-days are metal organic frameworks (MOFs).

Owing to their unique chemistry and physical properties, metal-organic Frameworks (MOFs) are an interesting class of materials which can be utilized for a wide array of applications. MOFs have been proposed to be used as catalysts for fuel cells, but their low intrinsic electronic conductivity hampered their utilization as-is. In this work, we present the synthesis and application of MOF-based PGM-free catalysts for oxygen reduction based on a unique metal-organic framework-carbon composite material. Benzene tricarboxylic acid-based MOFs were synthesized inside activated carbon (AC) with four different, first row transition metals: Mn, Fe, Co, and Cu. The MOFs@AC were analyzed electrochemically to measure their catalytic activity. Further physical and chemical characterizations were performed to measure the materials properties. The MOFs@AC are found to be conductive and active catalysts for oxygen reduction reaction in alkaline environment. Surprisingly, the Mn-based MOF@AC exhibits the best performance with onset potential of 0.9 V vs. RHE and almost four-electron mechanism, as opposed to most other known PGM-free catalysts, which show that Fe and Co as the most active metal. In this talk, we will share our most recent findings from studying these unique materials.