Encapsulating Cu nanoparticles into metal-organic frameworks for nonenzymatic glucose sensing

In this work, we applied metal-organic frameworks (MOFs) as a porous matrix to encapsulate Cu nanoparticles (NPs) for nonenzymatic glucose sensing in alkaline media . SEM and TEM confirmed that the size of the encapsulated Cu NPs ranges from 2.5 to 5   nm. The hybrid of Cu NPs encapsulated in ZIF-8 (Cu-in-ZIF-8) was further modified onto screen-printed electrodes for nonenzymatic sensing of glucose in alkaline medium. The porous structure of ZIF-8 are beneficial for the unimpeded diffusion of glucose and reaction product. And as a matrix for encapsulating Cu NPs, ZIF-8 also protect the Cu NPs from dissolution and agglomeration during the electrocatalytic process. For comparison, the electrochemical performance of Cu NPs loaded on ZIF-8 (Cu-on-ZIF-8) was also investigated and it is found that Cu-in-ZIF-8 exhibited higher activity and better stability for cyclic test toward the oxidation of glucose in alkaline media. Additionally, Cu-in-ZIF-8 based glucose sensor also shows a favorable sensitivity and selectivity.