State Key Laboratory of Chem/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan, 410082, P. R. China.
Jiangsu Collaborative Innovation Centre of Biomedical Functional Materials, Jiangsu Key Laboratory of New Power Batteries, School of Chemistry and Materials Science, Nanjing Normal University, Nanjing, Jiangsu, 210023, P. R. China.
Angew Chem Int Ed Engl. 2021 Mar 22;60(13):7297-7307. doi: 10.1002/anie.202015773. Epub 2021 Feb 22.
The nitrogenous nucleophile electrooxidation reaction (NOR) plays a vital role in the degradation and transformation of available nitrogen. Focusing on the NOR mediated by the β-Ni(OH) electrode, we decipher the transformation mechanism of the nitrogenous nucleophile. For the two-step NOR, proton-coupled electron transfer (PCET) is the bridge between electrocatalytic dehydrogenation from β-Ni(OH) to β-Ni(OH)O, and the spontaneous nucleophile dehydrogenative oxidation reaction. This theory can give a good explanation for hydrazine and primary amine oxidation reactions, but is insufficient for the urea oxidation reaction (UOR). Through operando tracing of bond rupture and formation processes during the UOR, as well as theoretical calculations, we propose a possible UOR mechanism whereby intramolecular coupling of the N-N bond, accompanied by PCET, hydration and rearrangement processes, results in high performance and ca. 100 % N selectivity. These discoveries clarify the evolution of nitrogenous molecules during the NOR, and they elucidate fundamental aspects of electrocatalysis involving nitrogen-containing species.
含氮亲核试剂电氧化反应（NOR）在有效氮的降解和转化中起着至关重要的作用。本研究聚焦于β-Ni(OH) 电极介导的 NOR，旨在解析含氮亲核试剂的转化机制。对于两步 NOR，质子耦合电子转移（PCET）是β-Ni(OH) 向β-Ni(OH)O 电化学脱氢以及自发亲核脱氢氧化反应的桥梁。该理论可以很好地解释肼和伯胺的氧化反应，但对于尿素氧化反应（UOR）则不够充分。通过 UOR 过程中键断裂和形成过程的 operando 追踪以及理论计算，我们提出了一种可能的 UOR 机制，即 N-N 键的分子内偶联，伴随着 PCET、水合和重排过程，实现了高活性和接近 100%的 N 选择性。这些发现阐明了 NOR 过程中含氮分子的演变，并阐明了涉及含氮物种的电催化的基本方面。
