Solid-state, reagent-free and one-step laser-induced synthesis of graphene-supported metal nanocomposites from metal leaves and application to glucose sensing

The laser-induced method to prepare three-dimensional (3D) porous graphene has been widely used in many fields owing to its low-cost, easy operation, maskless patterning and ease of mass production. Metal nanoparticles are further introduced on the surface of 3D graphene to enhance its property. The existing methods, however, such as laser irradiation and electrodeposition of metal precursor solution, suffer from many shortcomings, including complicated procedure of metal precursor solution preparation, strict experimental control, and poor adhesion of metal nanoparticles. Herein, a solid-state, reagent-free, and one-step laser-induced strategy has been developed for the fabrication of metal nanoparticle modified-3D porous graphene nanocomposites. Commercial transfer metal leaves were covered on a polyimide film followed by direct laser irradiation to produce 3D graphene nanocomposites modified with metal nanoparticles. The proposed method is versatile and applicable to incorporate various metal nanoparticles including gold silver, platinum, palladium, and copper. Furthermore, the 3D graphene nanocomposites modified with AuAg alloy nanoparticles were successfully synthesized in both 21 Karat (K) and 18K gold leaves. Its electrochemical characterization demonstrated that the synthesized 3D graphene-AuAg alloy nanocomposites exhibited excellent electrocatalytic properties. Finally, we fabricated LIG-AuAg alloy nanocomposites as enzyme-free flexible sensors for glucose detection. The LIG-18K electrodes exhibited the superior glucose sensitivity of 1194 μA mM-1 cm-2 and low detection limits of 0.21 μM. The LIG-21K nanocomposite sensors showed two linear ranges from 1 μM to 1 mM and 2 mM-20 mM with good sensitivity. Furthermore, the flexible glucose sensor showed good stability, sensitivity, and ability to sense in blood plasma samples. The proposed one-step fabrication of reagent-free and metal alloy nanoparticles on LIG with excellent electrochemical performance opens up possibilities for diversifying potential applications of sensing, water treatment and electrocatalysis.