Cobalt containing bimetallic ZIFs and their derivatives as OER electrocatalysts: A critical review

Oxygen evolution reaction (OER) is a crucial electrochemical reaction in metal-air batteries and water-splitting system. It is of utmost importance for these devices to achieve highly efficient clean energy production and storage. The zeolitic imidazolate frameworks (ZIFs) have received a lot of attention as a new type of crystalline porous materials due to their large surface area, high porosity, large pore volume, and easy functionalization as well as promising precursors to produce carbon-based electrocatalysts with high electrical conductivity. Cobalt-based bimetallic ZIFs with two distinct metal ions hold specific synergistic effects that demonstrate water oxidation performance and stability better than those of individual monometallic ZIFs. This review focuses on cobalt based bimetallic ZIFs; their advantages, synthesis and modification methods, derived compounds, synergistic effects, and activity of electrocatalysts during OER. We have summed up the application of bimetallic ZIFs and their derivatives in oxygen evolution reaction for the first time, that has sparked a lot of interest in this field. Finally, the future prospective of bimetallic ZIF-derived carbon-based materials for OER electrocatalysis is briefly discussed.