General approach to MOF-derived core-shell bimetallic oxide nanowires for fast response to glucose oxidation

摘要

One new type of electrochemical sensors for the effective glucose detection is fabricated based on the use of CuO_x@Co_3O_4 core-shell nanowires on Cu foam as electrocatalysts, which is synthesized through the stepwise process, including anodized nano-sized Cu(OH)_2 wires, Metal-organic frameworks (MOFs)-wrapped Cu(OH)_2 nanowires, and the following calcination. These as-made hierarchical composites exhibit the structural characteristics of CuO_x nanowires core and Co_3O_4 nanoparticles shell calcinated from the terminally attached mi-croporous ZIF-67. This type of glucose sensor compared to pure individual metal oxides exhibits higher sensitivity (27778 uA mM~(-1) cm~(-2) in the range from 0.1-1300.0 uM), lower detection limit (36 nM (S/N = 3)) and faster response time (～1 s), also displays satisfactory selectivity, reproducibility, and long-term storage stability. Meanwhile, it achieves well-pleasing results in the detection of glucose in real human blood serum compared to commercial sensors. In addition, other four types of self-supporting MOF-derived bimetallic oxides core-shell nanowire arrays on Cu foam are also prepared by adopting the similar three-step procedure, including CuO_x@ Fe_2O_3, CuO_x@NiO, CuO_x@CuO_x and CuO_x@ZnO core-shell nanowires, demonstrating the versatility of this method. These results confirm that our as-made MOF-derived bimetallic oxide based sensor of CuO_x@Co_3O_4 has a great potential application in the development of enzyme-free sensors for monitoring glucose.