Guidelines for reliable urea detection in electrocatalysis

Electrochemical urea synthesis offers a promising green alternative to fossil fuel-based approaches to support the increasing global demand for nitrogen fertilizers. Unfortunately, conventional urea detection methods produce inconsistent and unreliable results, hindering progress in this field. Both false positives and negatives can be observed depending on environmental factors and interfering chemicals. In this regard, we propose new rigorous 13C nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometry (LC-MS) protocols for accurate urea detection to analyze catalyst activity in an accessible and reproducible manner. For 13C NMR, we show the importance of identifying HCO3−/CO32− interference, including proper control experiments and internal standards. We suggest LC-MS as an alternative to existing detection methods due to its low detection limit, short measurement time, and compatibility with both 15N and 13C isotope experiments.