Regulating Open Pores to Engineer Interconnected Channels in CuCo Oxides for Enhanced Mass Transport toward...

The nonenzymatic glucose sensors with high oxidation states at metal sites can enable glucose oxidation for detection in human body fluids. However, the limited mass transfer in electrocatalysts, along with the inaccessibility within inner modified layers, continues to pose significant challenges for the performance of sensors. Herein, an ammonia-assisted etching strategy to engineer open pores within CuCo prussian blue analogue (CuCo PBA) cubes and interconnected channels in subsequently annealed CuCo oxides (CuCo PBA-N-A) is presented. The sensor achieves a high sensitivity of 1601.3 μA mM^-1 cm^-2 over the concentration of 2.9 μM to 5.2 mM, which is nearly 2.5 times that of its nonetched counterpart. Mechanistic investigation combining electrochemical analysis with finite element simulations directly correlates this enhancement to accelerated glucose diffusion through the engineered open pore channels, which ensures complete utilization of the active surface of electrocatalysts. The sensor also displays satisfactory selectivity, stability, and reproducibility. Moreover, great feasibility in human serum and beverages (recovery: 95.39-105.36%) was also exhibited by the CuCo PBA-N-A-based sensor. This pore-engineering strategy offers a high-performance glucose sensing platform, applicable to mass transport-dominated electrochemical devices.