Accelerated Reconstruction from Co-ZIF-L to CoOOH via a Tailored Electronic Structure of Cobalt for Oxygen Evolution

The Oxygen Evolution Reaction (OER) encounters an insurmountable kinetic bottleneck in water electrolysis due to the complex four-electron transfer process, while modulating the oxidation states of active sites holds promise for enhancing the OER performance. Here, we successfully prepare cobalt-based zeolitic imidazolate framework Co-ZIF-L on carbon cloth with high-valence Co sites (O-ZIF-CC) through a facile oxidation strategy by heat treatment under an air atmosphere and achieve rapid reconstruction from Co-ZIF-L to CoOOH during OER. The O-ZIF-CC, as an active MOF-based catalyst, exhibits a low overpotential (283 mV at 10 mA cm–2). The excellent electrocatalytic activity of the O-ZIF-CC can be ascribed to the introduction of high-valence Co sites, facilitating reconstruction to generate CoOOH at low potentials. This work provides a feasible approach for understanding the optimization of the performance of MOF-based electrocatalysts through valence-state tuning.