Guo Hele, Fu Siyu, Xue Guohao, Lai Feili, Liu Tianxi
The Key Laboratory of Synthetic and Biological Colloids Ministry of Education, School of Chemical and Material Engineering International Joint Research Laboratory for Nano Energy Composites Jiangnan University Wuxi 214122 P. R. China.
Department of Chemistry KU Leuven Celestijnenlaan 200F 3001 Leuven Belgium.
Small Sci. 2023 Dec 10;5(7):2300150. doi: 10.1002/smsc.202300150. eCollection 2025 Jul.
The electrocatalytic carbon-nitrogen (C-N) coupling, facilitating one-step urea synthesis under ambient conditions, holds great promise as a viable alternative to conventional protocols. However, developing efficient and low-cost electrocatalysts for C-N coupling remains a great challenge. Herein, a "bottom-up" strategy is proposed to synthesize multidimensional hybrid materials of ultrathin NiCu layered double hydroxide (LDH) nanosheets on carbon nanofiber (u-NiCu-LDH/CNF) through an ultrasonic-assisted solvothermal method. The NiCu-LDH nanosheets in the u-NiCu-LDH/CNF composite exhibit a significantly thinner morphology compared to NiCu-LDH/CNF prepared by conventional solvothermal without ultrasonic assistance. Leveraging its large specific surface area and well-exposed active sites, the u-NiCu-LDH/CNF demonstrates dramatically improved electrocatalytic activity in C-N coupling for urea production, leading to a satisfactory urea yield rate (19.43 mmol g h) and a high Faradaic efficiency (13.95%). Density functional theory calculations reveal that the C-N coupling step on the NiCu-LDH model starts through the reaction between *NO and *CO intermediates. This spontaneous C-N coupling process is beneficial in promoting high levels of urea yield. This work presents a facile approach for preparing 2D ultrathin LDH, showcasing tremendous prospects in electrocatalytic urea synthesis.
电催化碳氮（C-N）偶联在环境条件下促进一步法合成尿素，作为传统方法的可行替代方案具有很大的潜力。然而，开发用于C-N偶联的高效低成本电催化剂仍然是一个巨大的挑战。在此，提出了一种“自下而上”的策略，通过超声辅助溶剂热法在碳纳米纤维（u-NiCu-LDH/CNF）上合成超薄NiCu层状双氢氧化物（LDH）纳米片的多维杂化材料。与通过无超声辅助的传统溶剂热法制备的NiCu-LDH/CNF相比，u-NiCu-LDH/CNF复合材料中的NiCu-LDH纳米片呈现出明显更薄的形态。利用其大的比表面积和充分暴露的活性位点，u-NiCu-LDH/CNF在用于尿素生产的C-N偶联中表现出显著提高的电催化活性，导致令人满意的尿素产率（19.43 mmol g h）和高法拉第效率（13.95%）。密度泛函理论计算表明，NiCu-LDH模型上的C-N偶联步骤通过NO和CO中间体之间的反应开始。这种自发的C-N偶联过程有利于提高尿素产量。这项工作提出了一种制备二维超薄LDH的简便方法，在电催化尿素合成中展现出巨大的前景。
