Two-Step Electrodeposition of Polypyrrole Nanospheres and Pt Nanostars on Ni Foam for Electrochemical Detection of Ammonia–Nitrogen.

Designing and developing sensitive electrochemical sensors have always been paid attention to achieve the accurate detection of ammonia–nitrogen in the aqueous environment. Herein, a two-step electrodeposition route was used to achieve a Ni foam-supported polypyrrole nanospheres and Pt nanostars sensing electrode (Pt-PPy-Ni foam) for ammonia–nitrogen detection. After controlling the deposition time of Pt nanostars, the optimal Pt-PPy-Ni foam electrode exhibited greater electrocatalytic ability for ammonia oxidation reaction with a current density of 41.73 mA cm − 2 than that of Pt-Ni foam. This enhanced electrocatalytic ability could be attributed to the excellent adsorption of polypyrrole nanospheres for ammonia and the great catalytic activity of Pt nanostars for the ammonia oxidation reaction. This Pt-PPy-Ni foam electrode showed great detection performances with a sensitivity of 0.013 mA μ M − 1 , and a detection limit of 8.72 μ M. Moreover, accepted results were obtained for the recovery measurements of lake and seawater samples with recoveries from 101.05% to 102.27% and 90.73% to 91.70%. In addition, Pt-PPy-Ni foam sensor exhibited good anti-interference ability with low current charges, reproducibility (relative standard deviation = 1.58%) and stability (relative standard deviation = 6.11%), showing a great application potential. In the current study, Ni foam-supported PPy nanospheres and Pt nanostars (Pt-PPy-Ni foam) were fabricated via two-step and in-situ electrodeposition growth. Owing to the great electrocatalytic ability for ammonia oxidation reaction, Pt-PPy-Ni foam has been used as a sensitive electrode for ammonia-nitrogen detection with high sensitivity and good stability. [ABSTRACT FROM AUTHOR]