The Origin of the Electrocatalytic Activity for CO2 Reduction Associated with Metal-Organic Frameworks

There has been a rapid growth in the use of metal-organic framework (MOF) materials as electrocatalysts. However, simple anodic stripping analysis reveals that some well-known previously reported stable MOFs are in fact unstable at the negative potentials used to catalytically reduce CO2 in aqueous electrolyte media. Thus, it is the resulting metal nanoparticles derived from reduction of the MOFs rather than the MOFs themselves that are the electrocatalysts. The results reported herein therefore suggest that stability data and the origin of the activity for MOF electrocatalysts may need careful re-evaluation and that suitable strategies are needed to ensure that stable MOF electrocatalysts have been synthesized. The use of the readily accessible stripping analysis method provides a powerful tool to assess MOF stability under turnover conditions.