Muthukumar Pandi, Ullah Zakir, Zhang Xia, Ullah Habib, Liu Yuxiao, Li Linfeng, Tian Shengji, Zhou Xianlong, Anthony Savarimuthu Philip, Zuo Yunpeng, Lv Chade, Wang Xin, Wang Chundong
School of Integrated Circuits, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Consejo Superior de Investigaciones Científicas, Campus Universitari de Bellaterra, Cerdanyola del Vallès 08193, Spain.
J Am Chem Soc. 2025 Aug 20;147(33):29949-29960. doi: 10.1021/jacs.5c07066. Epub 2025 Aug 6.
Electrochemical nitrate reduction to ammonia (-NORR) offers a promising and sustainable alternative to the traditional Haber-Bosch process, enabling decentralized ammonia production under ambient conditions. However, the efficiency of -NORR is limited by the sluggish reaction kinetics due to the high activation energy barriers, poor mass transport, and the weaker adsorption affinity of the catalyst surface. In this study, we report the design and synthesis of a stable three-dimensional cobalt-based metal-organic framework (HUST-38), constructed from benzene-1,4-dicarboxylate ligand and DABCO, featuring water coordination within its framework. Impressively, the as-prepared HUST-38 delivers a high NH Faradaic efficiency of 95.7% and a high NH yield rate of 13.38 mg h mg at -0.6 V vs RHE, significantly outperforming the control sample of HUST-39 (3.98 mg h mg, nonwater coordination) and the mostly reported single-site solid electrocatalysts. Various measurements disclose that the labile solvent coordination in HUST-38 promotes water molecule accessibility to the catalytically active metal centers, hence augmenting localized *H enrichment and enhancing NO reduction. The theoretical calculations further substantiate the essential function of metal coordination microenvironments in modulating the electrocatalytic process, specifically by reducing free energy barriers associated with key reaction intermediates and enhancing the adsorption and desorption kinetics of reactants and products, ultimately leading to improved electrocatalytic activity and efficiency. The present work provides a foundation for the structural design of metal organic frameworks to develop efficient electrocatalysts.
电化学硝酸盐还原制氨（-NORR）为传统哈伯-博施法提供了一种有前景且可持续的替代方法，能够在环境条件下实现分散式氨生产。然而，-NORR的效率受到反应动力学缓慢的限制，这是由于高活化能垒、传质不佳以及催化剂表面较弱的吸附亲和力所致。在本研究中，我们报道了一种稳定的三维钴基金属有机框架（HUST-38）的设计与合成，它由对苯二甲酸配体和DABCO构建而成，其框架内具有水配位。令人印象深刻的是，所制备的HUST-38在相对于可逆氢电极（RHE）为-0.6 V时，实现了95.7%的高NH法拉第效率和13.38 mg h mg的高NH产率，显著优于HUST-39的对照样品（3.98 mg h mg，非水配位）以及大多数报道的单中心固体电催化剂。各种测量表明，HUST-38中不稳定的溶剂配位促进了水分子与催化活性金属中心的接触，从而增加了局部*H富集并增强了NO还原。理论计算进一步证实了金属配位微环境在调节电催化过程中的关键作用，具体表现为降低与关键反应中间体相关的自由能垒，并增强反应物和产物的吸附和解吸动力学，最终提高了电催化活性和效率。本工作为开发高效电催化剂的金属有机框架结构设计提供了基础。
