Template-Sacrificing Strategy for Three-Dimensional CoMo-Layered Double-Hydroxide Nanopolyhedra for Electrochemical Sensing of Nitrite

Electrochemical sensing is a widely adopted technique for the detection of target molecules even at a trace concentration. The key component in an electrochemical sensor is the electrode, for which layered double hydroxides (LDHs) have received significant attention because of their compositional tunability. However, it is still challenging to achieve mass production of LDHs as electrodes with structural integrity and regularity. Here, using Co-based metal organic frameworks (ZIF-67) as the precursor, a template-sacrificing strategy is reported to synthesize hollow CoMo-LDH (hCoMo-LDH) nanopolyhedra, which was used as a self-supporting electrode for electrochemical d hCoMo-LDH/CC sensing. Using nitrite as the target, our hCoMo-LDH/CC electrode exhibits an ultralow detection limit (0.01 mu M), a wide linear range (1 to 1500 mu M), and a striking sensitivity (1020 mu A.mM(-1).cm(-2)). Density functional theory calculations were employed to obtain a mechanistic understanding on the exceptional performance of the hCoMo-LDH nanopolyhedra resulted from the Mo doping. Furthermore, the electrode demonstrates excellent stability, strong anti-interference property, and good suitability in real water samples. Our work provides more opportunities for the design of self-supporting electrode in electrochemical sensing applications.