Pd-Cu nanospheres supported on MoC for the electrochemical sensing of nitrites.

The improper disposal in agricultural and industrial wastewater leads to high NO concentrations in the aquatic environment, which can cause cancer in humans and animals; thus, their quick and accurate detection is urgently needed to ensure public health and environmental safety. In this study, a reliable and selective electrochemical sensor consisting of Pd-Cu nanospheres (NSs) supported on molybdenum carbide was prepared via simple ultrasonication. Then, a glassy carbon electrode was realized using this composite (Pd-Cu-MoC-modified GCE) to test its electrocatalytic sensing for NO in a 0.1 M phosphate-buffered solution (PBS) solution via cyclic voltammetry and amperometry; at a low oxidation potential, the anodic peak current of NO detected by this electrode was significantly higher than that of its unmodified and other modified electrodes. The sensor showed a broad linear response in the 5-165-nM NO concentration range, with a low detection limit (0.35 nM in 0.1 M PBS) and high sensitivity (3.308 μAnM cm). Moreover, the fabricated electrode was successfully applied for detecting nitrites in sausages, river water, and milk, showing also good recovery.