MOF-derived CuO/CNT for high sensitivity and fast response glucose sensing

TL;DR: MOF-derived CuO/CNT composites exhibit high sensitivity (4.34 mA mM−1 cm−2) and fast response time (0.45 s) for glucose sensing, outperforming CuO-based sensors, due to synergistic effects of MOF-derived CuO and CNT enhancing active sites and conductivity.

Abstract: The weak conductivity and sluggish electrochemical reaction kinetics lead to low sensitivity and slow response speed of CuO-based non-enzymatic glucose sensors (NEGSs). Therefore, developing CuO-based NEGSs with high sensitivity, excellent selectivity, and fast response is vital for monitoring and analyzing the glucose concentration of humans and beverages. In this work, the MOF-derived porous CuO nanosheets were synthesized by the bottom-up and annealing methods, and CuO/CNT(7:3) NEGSs were prepared. The CuO/CNT(7:3) NEGSs exhibit good glucose sensing performance, including a high sensitivity of 4.34 mA mM−1 cm−2 (about 3 times higher than that of CuO NEGSs) in a linear range of 0.5 µM-1 mM, ultra-fast response time of 0.45 s (superior to most reports on NEGSs), and favorable selectivity. The superior glucose sensing properties of CuO/CNT(7:3) NEGSs are due to the synergistic effect of MOF-derived CuO and CNT. MOF-derived CuO nanosheets with porous structures provide more active sites resulting in good sensing properties, meanwhile, CNT improves the conductivity of composites, enhances the ion diffusion in the electrode, and accelerates the electron transfer at the electrode/electrolyte interface, leading to higher sensitivity and faster response speed. Moreover, the CuO/CNT(7:3) NEGSs also show a good recovery for glucose detection in human urine and beverages. This work suggests that the CuO/CNT(7:3) composites are a prospective electrode material for high-performance NEGSs.