One-step synthesis of 2D@3D hollow Prussian blue analogue as a high-performance bifunctional electrochemical sensor.

Prussian blue analogues (PBAs) are a family of classic coordination polymers. They have been widely applied in various fields including electrochemical sensors. Cubic nanoparticle structure is their common morphology. It is still a great challenge to design a hollow and two-dimensional (2D) PBA material. Of course, it will be a significant surprise if a hollow cube and 2D sheet can be integrated into one material. In this work, we designed a simple one-step synthetic strategy and resolved the above difficulty, wherein a hollow cubic PBA covered by 2D ultrathin nanosheets was successfully constructed, namely hollow tremella-like PBA (HTPBA). Furthermore, Ni foam (NF) as a substrate was introduced to obtain a self-supporting HTPBA/NF-12 electrode. HTPBA/NF-12, as a bifunctional electrochemical sensor electrode, exhibited distinguished catalytic performance towards glucose and nitrite, including remarkable selectivity, reproducibility, sensitivity for glucose (21 410 μA mM cm) and nitrite (1248 μA mM cm), wide linear range of 2-1250 μM and 5-3380 μM, along with low detection limit of 0.056 μM and 0.38 μM, respectively. More importantly, HTPBA/NF-12 electrodes possessed good reusability and practicability even in goat serum. In this study, we developed a simple and effective strategy to fabricate 2D@3D PBA material with excellent electrocatalytic activity and provide a totally new viewpoint in the PBA sensing field.