Abstract: This study introduces an undergraduate teaching experiment that employs electrochemical methods to directionally convert urea into high-value nitrite. A Co-doped Ni₃S₂ (Co-Ni₃S₂) catalyst was designed for the catalytic conversion of urea molecules. Using Co-Ni₃S₂ as the anode catalyst in an alkaline urea electrolyte, the electrocatalytic performance was evaluated via a three-electrode testing system. The effects of applied potential and Co-doping strategy on product selectivity were systematically investigated to identify optimal reaction conditions. Quantitative detection of NO₂^- was performed, and key evaluation metrics such as Faradaic efficiency and yield rate were calculated. This experiment integrates inorganic material preparation, electrochemical testing, and analytical chemistry techniques, enabling students to appreciate the significance of urea resource utilization (“turning waste into wealth”) and the economic value of NO₂^- in the chemical industry. The experiment enhances students’ scientific thinking, experimental design, and research innovation capabilities, demonstrating strong feasibility and educational value.

Key words: Comprehensive experiment, Electrochemistry, Urea oxidation reaction (UOR), Nitrite, Turn waste into wealth