Hierarchical confinement of Prussian blue nanoparticles via NH₂-MIL-88B(Fe): Rational design and electrocatalytic application

The design of Prussian blue nanoparticles (PB NPs) with satisfied electrocatalytic ability and stability is still challenging. Herein, a hierarchical confinement strategy of PB NPs is proposed using NH₂MIL-88B(Fe) (denoted herein as NH₂MIL) as both self-confined template and Fe³⁺ sources, K₃[Fe(CN)₃] as precursor. The catalytic synthesis of PB NPs is further achieved during the hydrothermal process at 100 °C for 1 h. The as-prepared PB@NH₂MIL exhibits the morphology of “sea cucumber”, retaining the intrinsic skeleton of NH₂MIL dotted with lots of PB NPs (<40 nm). In addition, the initial coordination of [Fe(CN)₃]^3- with the active free coordination sites of NH₂MIL results in the coatom phenomenon between NH₂MIL and PB NPs. Thus, the as-prepared PB@NH₂MIL possesses the efficient electronic transmission, the enhanced electrocatalytic properties as well as stability under prolonged electrochemical measurements. Finally, the as-prepared PB@NH₂MIL can be used as artificial peroxidase for the electrochemical detection of H₂O₂ with a wider linear range (0.01–1000 μM) and low detection limit (3 nM).