Jiao Yuye, Yang Biao, Li Tong, Song Yurou, Jiang Jingwen, Wang Chen, Jin Dingfeng, Hu Zhiqiang, Jiao Siyu, Chen Guanghao, Lu Shijie, Feng Jianyong, Hou Jungang
State Key Laboratory of Fine Chemical, Frontiers Science Center for Smart Materials Oriented Chemical Engineering, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, P. R. China.
Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, School of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, P. R. China.
J Am Chem Soc. 2025 Sep 3;147(35):31679-31688. doi: 10.1021/jacs.5c07718. Epub 2025 Jul 29.
The formation of the C-N bond plays a pivotal role in the ecofriendly synthesis of fertilizers, pharmaceuticals, and chemical products. Photoelectrocatalytic (PEC) upgrading of biomass derivatives powered by renewable energy offers a green and sustainable catalytic strategy to generate formamide, which has scarcely been explored. Herein, we developed a promising PEC approach for constructing a C-N bond to synthesize formamide through the coupling of the oxidation of biomass derivatives. Taking glucose as a representative, we achieved a high formamide yield of 976.6 mmol m h at 1.2 V versus a reversible hydrogen electrode (vs RHE) and Faraday efficiency (FE), >81% at 0.8-1.2 V vs RHE by integrated photoanode, representing excellent performance in comparison to previous reports for electrosynthesis (FE < 43.2%). Moreover, a large-area (5 × 5 cm) photoanode was also applied for formamide synthesis, representing an industrial current of 100 mA with FE > 78.1%. To ascertain the mechanism, in situ photoelectrochemical spectroscopy and density functional theory calculations confirmed that the formaldehyde radical (*CHO) intermediate was formed by the direct oxidation of photogenerated holes instead of the hydroxyl radical (*OH) attack to break the C-C bond, and then the C-N bond was established by coupling with *CHO and the nitrogen radical (*NH) formed by NH to form formamide. The substrate could be converted from glucose to biomass-derived aldoses (or polyols), demonstrating its superior reaction suitability. This work deepened the understanding of the C-N coupling mechanism and provided an effective PEC approach for the conversion of biomass derivatives into valuable chemicals.
C-N键的形成在肥料、药品和化学产品的绿色合成中起着关键作用。由可再生能源驱动的生物质衍生物的光电催化（PEC）升级提供了一种绿色且可持续的催化策略来生成甲酰胺，而这方面的研究几乎尚未开展。在此，我们开发了一种有前景的PEC方法，通过生物质衍生物的氧化偶联来构建C-N键以合成甲酰胺。以葡萄糖为代表，我们在相对于可逆氢电极（vs RHE）为1.2 V时实现了976.6 mmol m⁻² h⁻¹的高甲酰胺产率，通过集成光阳极在0.8 - 1.2 V vs RHE时法拉第效率（FE）>81%，与先前报道的电合成相比表现优异（FE < 43.2%）。此外，还将大面积（5×5 cm）的光阳极应用于甲酰胺合成，实现了100 mA的工业电流且FE > 78.1%。为确定反应机理，原位光电化学光谱和密度泛函理论计算证实，甲醛自由基（*CHO）中间体是由光生空穴直接氧化形成，而非羟基自由基（OH）攻击断裂C-C键形成，然后通过CHO与NH形成的氮自由基（*NH）偶联形成甲酰胺来建立C-N键。底物可以从葡萄糖转化为生物质衍生的醛糖（或多元醇），表明其具有卓越的反应适用性。这项工作加深了对C-N偶联机理的理解，并为将生物质衍生物转化为有价值的化学品提供了一种有效的PEC方法。
