Refined Protocol for Improving Accuracy and Reliability in Urea Quantification During Electrochemical C─N Coupling Reactions.

Abstract

Promoted by the growing demand for sustainable carbon and nitrogen cycling, electrochemical C─N coupling in urea synthesis has attracted intensive interest. Urea quantification provides the basis for an in-depth understanding of structure-performance correlations and the iterative optimization of performance. However, current urea quantification methods have non-negligible drawbacks, largely bringing about false positive or negatives risks. Herein, the most accessible and commonly used quantification techniques, namely the diacetylmonoxime-thiosemicarbazide and Urease-based methods, are comprehensively re-assessed. The adverse impacts caused by nitrite, metallic impurities, and standard curve protocol are thoroughly identified. Most importantly, direct problem-solving strategies are proposed to rule out those confounding factors by chemical pre-reduction, galvanic replacement, and refinement of the standard curve protocol, respectively. This refined urea quantification method can solidify the reproduction of urea electrosynthesis studies and thus promote the sound development of this emerging field.