A review: Metal-organic framework based electrocatalysts for methanol electro-oxidation reaction

Energy crisis is the most important issue of the current society, which needs to be addressed on a priority base. A number of energy sources are under research consideration to fulfil the energy needs of the modern society. Methanol electro-oxidation is one of the best energy sources, but still requires electrocatalytically active materials. Different materials, especially metal-organic frameworks (MOFs), have been extensively studied in the last few years. This review summarizes recent studies on the electrocatalytic methanol oxidation reaction, concluding that Ni-based MOFs materials were favoured compared to other metal-based MOF. Additionally, the synergism of two metals, especially Ni and Fe provided an outstanding response for the methanol electro-oxidation reaction. Moreover, the activity of MOFs was further improved as the size of materials was reduced. The introduction of carbon-based support, such as reduced graphene oxide (rGO), also increased catalytic performances due to the well dispersion of the catalyst on the surface. The dispersion of the active material enhanced the reactive surface area and the number of active reaction spots. Thus, performances of materials toward methanol oxidation reaction can be further enhanced if the size of the catalyst is reduced and morphology is controlled in terms of a large number of pores. Similarly, the deposition of the electrocatalyst on the surface of a conductive support avoids agglomeration and facilitates the electron transport, thus enhancing electrocatalytic performances. In addition, multi-metal (i.e., tri and tetra-metal) based materials are needed to be further studied to develop the most efficient electrocatalyst for electrochemical methanol oxidation.