Surface adsorption guided design of semicrystalline nickel-iron hydroxide for highly-sensitive glucose sensing

Non-enzymatic glucose sensors, using electrochemically active sensing materials, is of great importance to efficiently monitoring and analyzing the glucose concentration in human body fluids in a simple and rapid manner. However, the remaining disadvantages such as complicated fabrication process, relatively lower sensitivity, and poor stability still limit the actual applications of enzyme-free sensors. On the guide of theoretical simulation, herein, we report an ultrafast, simple, and controllable strategy through one-step chemical corrosion of nickel foam (NF), to prepare semicrystalline nickel-iron hydroxide (NiFeOxHy) as an electrochemical glucose sensing platform. Owing to the short etching time, the NiFeOxHy surface coating with a lower crystallinity degree contains a few crystalline domains act as the adsorption sites. Compared to the pristine NF which is not favorable for glucose adsorption, NiFeOxHy/NF sensor exhibits enlarged electrochemical surface area, superior hydrophilic ability and lower charge transfer resistance, thus promoting the surface adsorption of glucose molecules and accelerating the charge transport kinetics during the glucose sensing. Consequently, NiFeOxHy/NF sensor shows an ultrahigh sensitivity of 6004 μA mM−1 cm−2, along with a high glucose selectivity when exposed to various interferents and superior cycling stability. In addition, the etching-derived NiFeOxHy/NF sensor also works in a blood serum sample. This work therefore offers a convenient and rapid approach to sensor fabrication for high-performance glucose detection.