High-performance hydrogen peroxide micro-sensors based on laser-induced fabrication of graphene@Ag electrodes

Highlights: • A uniform and robust electrode was fabricated by defocused laser ablation method. • Laminar structure with defects and micropores of LIG can offer numerous active sites. • LIG@Ag electrode shows excellent catalytic performance on hydrogen peroxide. • This method can provide a versatile platform for electrochemical and bio-sensors. Micro-electrodes based on noble-metal-nanoparticles-anchored graphene have attracted widespread attention in electrochemical sensing due to highly efficient catalytic characteristics. Herein, we report a rapid preparation method of laser-induced graphene electrodes anchored with silver nanoparticles (LIG@Ag) for high-resolution hydrogen peroxide detection. This one-step defocused laser ablation method can enable uniform distribution of silver nanoparticles strongly anchored on LIG nanosheets featured with layered structure with defects and micropores. The spatial confinement effect of LIG can inhibit the size increase of Ag NPs, and Ag NP also prevents the restacking of graphene nanosheets. Benefited by the synergistic effect of Ag NPs and LIG nanosheets, the LIG@Ag electrode presented an excellent electrochemical performance in many ways, e.g., non-enzymatic detection of hydrogen peroxide with a wide linear range from 0.01 to 0.55 mM (R² = 0.995) and 0.55 to 2.61 mM (R² = 0.997), low detection limit approximately 2.8 μM, rapid response (~3 s), high sensitivity (28.6 μA mM⁻¹ cm⁻²), long-term stability (over 45 times in a week), superior selectivity at biological interferences, and excellent reproducibility. Since the LIG@Ag electrode has the characteristics of superior electrical conductivity, mechanical flexibility, and lightweight, this method has broad prospects in the large-scale fabrication of smart sensing devices.