3D pothole-rich hierarchical carbon framework-encapsulated Ni nanoparticles for highly selective nonenzymatic cysteine detection

3D pothole-rich hierarchical amorphous carbon network-encapsulated Ni nanoparticles (Ni NPs) electrocatalytic material (3D-Ni@AC) is successfully designed and synthesized via a facile in-situ NaCl template-removal method for electrochemical non-enzymatic cysteine (CySH) detection. 3D-Ni@AC assembled from the carbon nanosheet encapsulated Ni NPs layer-by-layer interlaced possesses interconnected porous network structure, the network structure of carbon nano-layer can effectively prevent the agglomeration of Ni NPs, ensuring full utilization of active materials. Cyclic voltammetric (CV) study showed that 3D-Ni@AC/GCE displayed high electrocatalytic activity toward the oxidation of CySH compared to template-free Ni@AC/GCE. The unique structure, the enlarged specific surface area and the synergistic effects from the excellent conductivity of carbon frame and Ni NPs provide fast electrons/ions transfer and favorable electrocatalytic activity for the electro-oxidation of CySH. In an electrolyte solution of 0.1 M NaOH, the constructed CySH sensor offered a high sensitivity (0.079 mA/cm 2 μM), a low detection limit (0.15 μM) and a wide linear range (from 0.8 to 85 μM). The fabricated high electrocatalytic performance sensor was utilized to monitor the CySH levels in urine and serum, and satisfactory results were gained. Moreover, 3D-Ni@AC electrode showed good reproducibility, stability, and anti-interference ability, indicating that 3D-Ni@AC can be used as a good electrocatalytic material in practical biological applications.