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 $\mu$M${}^{-1}$, and a detection limit of 8.72 $\mu$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.

为了实现水环境中氨氮的准确检测，设计和开发灵敏的电化学传感器一直受到人们的重视。在此，采用两步电沉积路线来实现用于氨氮检测的泡沫镍支撑的聚吡咯纳米球和铂纳米星传感电极（Pt-PPy-Ni泡沫）。控制Pt纳米星的沉积时间后，最优的Pt-PPy-Ni泡沫电极在电流密度为41.73 mA cm时表现出更强的氨氧化反应电催化能力${}^{-2}$优于 Pt-Ni 泡沫。这种增强的电催化能力可归因于聚吡咯纳米球对氨的优异吸附以及Pt纳米星对氨氧化反应的良好催化活性。这种 Pt-PPy-Ni 泡沫电极表现出出色的检测性能，灵敏度为 0.013 mA$\mu$中号${}^{-1}$，检测限为 8.72$\mu$此外，湖水和海水样品的回收率测量也得到了认可，回收率分别为101.05%~102.27%和90.73%~91.70%。此外，Pt-PPy-Ni泡沫传感器在低电流充电下表现出良好的抗干扰能力、重现性（相对标准偏差=1.58%）和稳定性（相对标准偏差=6.11%），显示出巨大的应用潜力。