Carbon fibre-supported hierarchical NiCo layered double hydroxide nanosheets as non-enzymatic glucose sensors for sport drinks and serum

We report a systematic study of carbon fibre (CF)-supported NiCo layered double hydroxide nanosheets (LDHNs) with and without heat treatment at 200 and 400 °C (CF-NiCo LDHN₂₀₀ and CF-NiCo oxide nanoparticles (NPs), respectively) as catalysts and sensors for glucose oxidation reactions (GORs). Tafel measurements for the GORs showed that the exchange current density of CF-NiCo LDHN was 1.91 × 10⁻³ mA·cm⁻² at an early rest potential of −0.422 V. This was markedly higher than those of CF-NiCo LDHN₂₀₀ (1.22 × 10⁻³ mA·cm⁻² at − 0.352 V) and CF-NiCo oxide NP (1.18 × 10⁻³ mA·cm⁻² at −0.327 V). The electron transfer number and Tafel slopes suggested that the glucose dehydrogenation step and one-electron release occurred first in the GORs. Amperometric measurements revealed high recoveries (101.92% and 98.92%) and low relative standard deviations (1.98% and 2.34%) for the determination of glucose using the CF-NiCo LDHN in sports drink samples and human serum.