Highly Sensitive Determination of Ammonia Nitrogen by Nanocubic Copper Prepared by Direct Electrochemical Deposition (Supporting Information)

The precise and rapid detection of ammonia nitrogen is of paramount importance in safeguarding water environments. In this study, we introduce a novel approach for electrochemical ammonia sensing using nanocubic copper electrodes, fabricated through a straightforward electrodeposition technique. A comprehensive characterization of the copper electrode sheds light on the pivotal role of deposition in shaping the morphology of copper particles, subsequently impacting the ammonia sensing capabilities. Through an in-depth investigation of the electrochemical behavior of nanocubic copper electrodes, we unveil how ammonia enhances electron transfer during copper oxidation by forming robust coordination with Cu(II) and simultaneously disrupting the oxide layer on the copper surface. This synergistic effect process has been effectively harnessed for the rapid electrochemical quantification of ammonia nitrogen. Linear scan voltammetry results reveal a direct relationship between peak currents and ammonia nitrogen concentrations spanning the broad range of 0.1–100 ppm. Notably, the nanocubic copper electrode exhibits a low detection limit, exceptional resistance to interference and impressive repeatability. Moreover, our practical testing in real water samples show the nanocubic copper electrode’s superior performance over the spectrometric method in determining ammonia nitrogen concentrations. These findings underscore the potential of the nanocubic copper electrode for high-performance ammonia sensing applications.