Graphene wrapped porous Co3O4/NiCo2O4 double-shelled nanocages with enhanced electrocatalytic performance for glucose sensor

Graphene (G) wrapped porous Co 3 O 4 /NiCo 2 O 4 double-shelled nanocages (Co 3 O 4 /NiCo 2 O 4 DSNCs@G) were prepared by the formation of Co 3 O 4 /NiCo 2 O 4 DSNCs using zeolite imidazole frameworks-67 as template with the subsequent calcination and package of G by hydrothermal method. The abundant accessible active sites provided by the porous structure of Co 3 O 4 /NiCo 2 O 4 DSNCs and efficient electron transport pathways for electrocatalytic reaction offered by the high conductive G worked very well together in a ferocious synergy, which endowed Co 3 O 4 /NiCo 2 O 4 DSNCs@G with excellent electrocatalytic behaviors for determining glucose. A comparison between Co 3 O 4 /NiCo 2 O 4 DSNCs without G packing and Co 3 O 4 /NiCo 2 O 4 DSNCs@G showed that former had linear response window concentrations of 0.01-3.52   mM (correlation coefficient   =   0.999), detection limit of 0.744   μM (S/N   =   3) and sensitivity of 0.196   mA   mM −1   cm −2 , whereas the latter exhibited linear response window concentrations of 0.01-3.52   mM (correlation coefficient   =   0.999), detection limit of 0.384   μM (S/N   =   3) and sensitivity of 0.304   mA   mM −1   cm −2 . The combination of Co 3 O 4 /NiCo 2 O 4 DSNCs and G was a meaningful strategy to fabricate high-performance non-enzyme glucose sensors with low detection limit, good selectivity and high sensitivity.