Electrochemical Evolution of Pore-Confined Metallic Molybdenum in a Metal–Organic Framework (MOF) for All-MOF-Based Pseudocapacitors

In this study, metallic molybdenum nanoparticles confined in the nanopores of a zirconium-based MOF (Zr-MOF), MOF-808, are prepared by a self-limiting decoration of spatially isolated Mo(VI) sites on the hexa-zirconium nodes of MOF-808, followed by the electrochemical reduction of Mo(VI) to metallic Mo. The obtained pore-confined Mo exhibits reversible redox activity in a neutral aqueous electrolyte and serves as the pseudocapacitive material for negative electrodes. By introducing another MOF-based pseudocapacitive material that can be used for positive electrodes, a manganese-decorated Zr-MOF-carbon nanotube nanocomposite, as a demonstration, all-Zr-MOF-based asymmetric pseudocapacitors with an aqueous electrolyte are fabricated.