Activating Ni nanoparticles into Ni single atoms by N doping for high-performance electrochemical sensing of glucose

N doping is an effective strategy for regulating the electrocatalytic activity of nanomaterials. However, the mechanism of N doping enhancing electrocatalysis is still unclear. In view of the important role of N doping in inducing the preparation of metal single atoms, could the effect of N doping on electrocatalytic activity be caused by metal single atoms? In the work, two types of nanocomposites were prepared by anchoring Ni nanoparticles into carbon nanomaterials (C) and N doped carbon nanomaterials (NC), respectively. Electrochemical studies found that N doping significantly enhanced the electrocatalytic activity of Ni nanoparticles for glucose oxidation. Further studies show that NC was loaded with not only Ni nanoparticles, but also Ni single atoms (NiSA), which are usually easily overlooked. Moreover, it is interesting to find that NiSA exhibit excellent electrocatalytic activity toward glucose oxidation, even stronger than Ni nanoparticles. The sensor based on NiSA/NC could detect glucose from 0.0008 mM to 1.124 mM with a high sensitivity of 799.43 µA mM−1·cm−2 and a low detection limit of 0.22 µM. Therefore, it can be inferred that the reason N doping boosting the electrocatalytic activity may be attributed to the presence of NiSA. This work not only provides a new perspective to explain the mechanism of N doping on electrocatalysis, but also for the first time demonstrated the excellent electrocatalytic ability of NiSA toward glucose oxidation.