Self-reduction of bimetallic nanoparticles on flexible MXene-graphene electrodes for simultaneous detection of ascorbic acid, dopamine, and uric acid

Three-dimensional (3D) porous laser-scribed graphene (LSG) is a potential electrode material for flexible elec-trochemical sensors due to its high efficiency and low cost. However, the growth of nanoparticles usually de-pends on reducers or harsh conditions, which limit the application of flexible biosensors. To resolve this issue, 2D MXene nanosheets were applied to functionalize 3D LSG sheets with a C-O-Ti covalent crosslink and obtain an LSG-MXene hybrid scaffold. The shape-controlled Au-Pd bimetallic nanoparticles were synthesized on the surface of LSG-MXene by a self-reduction process at room temperature for 6 min to enhance its catalytic performance. As a proof of concept, the obtained hybrid nanocomposite was used to assess ascorbic acid (AA, 10-1600 mu M), dopamine (DA, 12-240 mu M), and uric acid (UA, 8-100, 200-800 mu M). The fabricated sensor exhibited a low detection limit (S/N = 3) of 3 mu M AA, 0.13 mu M DA, and 1.47 mu M UA. Furthermore, the Au-Pd/MXene/LSG was successfully applied to determine AA, DA, and UA in urine samples. Predictably, these outstanding performance sensors have great potential in flexible and wearable electronics.

Automated summary

Two-dimensional MXene nanosheets were used to functionalize three-dimensional laser-scribed graphene (LSG) and obtain an LSG-MXene hybrid scaffold. Shape-controlled Au-Pd bimetallic nanoparticles were synthesized on the LSG-MXene surface to enhance its catalytic performance. The fabricated sensor showed low detection limits for ascorbic acid, dopamine, and uric acid and can be used for their determination in urine samples.