One-Step Controlled Electrodeposition Fabrication of Ternary PtNiCo Nanosheets for Electrocatalytic Ammonia–Nitrogen Sensing

The development of high-performance electrochemical sensors is crucial for ammonia–nitrogen detection. Therefore, in this study, we successfully prepared one ternary PtNiCo nanosheet via the one-step electrodeposition technique. The ratio of H2PtCl6·6H2O, Ni(NO3)2·6H2O and Co(NO3)2·6H2O and electrodeposition time were controlled. Under optimal conditions, Pt6Ni2Co2-2000 demonstrated outstanding electrocatalytic performance, exhibiting a high oxidation peak current of 45.27 mA and excellent long-term stability, retaining 88.09% of its activity after 12 h. Furthermore, the sensing performance of Pt6Ni2Co2-2000 was evaluated, revealing high sensitivity (10.01 μA μM−1), a low detection limit (0.688 µM), strong anti-interference capability, great reusability, great reproducibility, and remarkable long-term stability. Additionally, recovery tests conducted in tap water, lake water, and seawater yielded highly favorable results. This study demonstrated that designing Pt-based alloys can not only enhance the electrochemical performance of Pt but also serve as an effective strategy for improving electrocatalytic ammonia oxidation and ammonia–nitrogen detection.