Selective design of MOF-derived electrocatalytic interphases by potential-driven surface reconstruction

• Precise potential-induced surface reconstruction of a Co-MOF was carried out. • Relationship between the applied potential and the chemical composition is shown. • Composition-dependent GOR electrocatalytic performance is demonstrated. Metal-organic frameworks (MOFs) can be used as precursors for the directed synthesis of derived materials with enhanced performance for electrocatalysis. Herein, we report on an in-situ electrochemical strategy for the selective synthesis of hybrid electrocatalysts using a cobalt MOF (2D-CoMOF) as a precursor for constructing electrochemical sensors to monitor the glucose oxidation reaction (GOR). By using in-situ Raman spectroelectrochemistry, it is demonstrated that a precise control of the applied potential during amperometric treatment of 2D-CoMOF can promote the generation of derived heterostructures in which the original MOF coexists with metal oxides and/or oxyhydroxides (MOF-MOx) with different compositions. The so-prepared electrodes exhibit high electroactive surface areas, a high number of electrocatalytically active cobalt sites and an efficient charge transport across the catalytic film. Moreover, their composition-dependent electrocatalytic performance for the glucose oxidation reaction is examined, establishing a relationship between the applied potential, the macroscopic chemical composition of the heterostructure and the electrocatalytic performance for glucose sensing. In particular, the hybrid phases consisting of Co-MOF/Co 3 O 4 /CoOOH display superior electrocatalytic sensing performance with a wide linear concentration range and high sensitivity. The present work emphasizes the significance that the precise control of the applied potential has on the electrochemically-assisted MOF transformation for developing highly efficient MOF-derived electrocatalysts.