In situ electrodeposition of Ni(OH)₂ nanoparticles for highly sensitive electrochemical detection of ascorbic acid

Nickel hydroxide (Ni(OH)₂) nanoparticles were prepared by in situ electrodeposition onto carbon paper (CP) through comprehensive optimization of the deposition parameters, aiming to achieve highly sensitive electrochemical determination of ascorbic acid (AA). The microstructure, elemental composition and electrochemical characteristics of Ni(OH)₂/CP were systematically characterized by SEM, EDS, XPS and a series of electrochemical tests. The results verified the successful modification of Ni(OH)₂ nanoparticles on the CP substrate, which enlarged the electroactive surface area and lowered the charge-transfer resistance, thus boosting the electrochemical sensing performance. The electrocatalytic oxidation of AA on Ni(OH)₂/CP belonged to a diffusion-controlled process. Based on these merits, the as-fabricated sensor showed a broad detection range, outstanding sensitivity and a low limit of detection (LOD) of 1.65 μM. In addition, the sensor exhibited favorable repeatability, excellent long-term/short-term stability, strong anti-interference ability, and satisfactory recoveries of 97.50%-102.0% in real sample tests, validating its great potential for practical applicability.