Advanced on-site glucose sensing platform based on a new architecture of free-standing hollow Cu(OH)2 nanotubes decorated with CoNi-LDH nanosheets on graphite screen-printed electrode

Abstract

The planned design of nanocomposites combined with manageable production processes, which can offer controllability over the nanomaterial structure, promises the practical applications of functional nanomaterials. Hollow core–shell nanostructure architectures represent an emerging category of advanced functional nanomaterials, whose benefits derived from their notable properties may be hampered by complicated construction processes, especially in the sensing domain. In this regard, we designed a highly porous three-dimensional array of hierarchical hetero Cu(OH)₂@CoNi-LDH core–shell nanotubes via a quick, very simple, green, and highly controllable three-step in situ method; they were directly grown on a glassy carbon electrode to fabricate an enzyme-free glucose sensor. By virtue of an open structure containing a hollow conductive core and a highly porous catalytic active shell, which were both synthesized by the in situ method, hierarchical self-standing core–shell nanotubes were obtained. They provided an enlarged active surface area, highly accessible catalytic sites, faster electron transfer, effortless electrolyte ion diffusion pathways, and structural stability, thus leading to improved electrocatalytic performances and durability towards glucose electro-oxidation; this was reflected by the fast sensitive responses of the as-prepared sensor towards glucose and comparable results with the automatic biochemistry analyzer used in hospitals in real sample analysis. Moreover, the commercialization capability of the proposed sensor was evaluated analogously by directly grown hierarchical Cu(OH)₂@CoNi-LDH core–shell nanotubes on graphite screen-printed exposable electrodes through a 3-step in situ method. Cu(OH)₂@CoNi-LDH NS-NTs/GSPE showed accurate responses towards glucose, lack of any fouling effect of the electrocatalyst layer over a wide range of glucose concentrations and comparable results with that of a commercial glucometer in real sample analysis, which revealed high sensitivity, selectivity, and durability of the low-cost on-site sensor as well as excellent versatility of its fabrication method. Thus, the self-supporting, cost-affordable, facile, and fast electrode fabrication procedure with versatility and meticulous structural controllability presented in this research provides a new architecture for the advancement of high-performance electrochemical sensors and miniaturized detection devices.