Core-shell composite of CuS nanocages and NiCo layered double hydroxide nanosheets with modulated electron structure as “two birds with one Stone” glucose oxidation electrocatalysts

Abstract

The demands to overcome the intrinsic agglomeration of 2D layered double hydroxides (LDHs) and accelerate electron transfer kinetics in electrocatalysis highlight the desirability in rationally designing hollow transition metal sulfides (TMSs) as feasible supports for 2D structures. Herein, the well-designed CuS nanocages covered by NiCo LDHs nanosheets with the optimal Ni/Co ratio of 1:2 (CuS NCs@Ni1Co2 LDHs) were successfully prepared for the first time through sulfidation coupled with a coordinated etching and precipitation (CEP) method. As a nano-electrocatalyst for glucose detection, CuS NCs@Ni1Co2 LDHs not only demonstrated the advantage of the unique structure with outstanding mass diffusion, but also promoted electrocatalytic activities accompanied with fast electron transfer. Furthermore, density functional theory (DFT) calculations disclosed that the coupling between CuS NCs and Ni1Co2 LDHs enabled the increased glucose absorption energy and the improved conductivity. Significantly, the CuS NCs@Ni1Co2 LDHs modified electrode exhibited superior electrocatalytic performance with the sensitivity as high as 2236.4 μM mM−1 cm−2 combined with an ultralow limit detection of 0.18 μM, wide linear range (0.001–4.6 mM), and fast current response (1 s). Overall, the proposed electrochemical sensors shed light on the favorable incorporation of 3D hollow TMSs and 2D LDHs for high-performance glucose monitoring.