MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150080, PR China; College of Chemistry and Chemical Engineering, Henan Institute of Science and Technology, Xinxiang 453003, PR China.
MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150080, PR China.
J Hazard Mater. 2023 Mar 15;446:130679. doi: 10.1016/j.jhazmat.2022.130679. Epub 2022 Dec 26.
The development of electrochemical nitrate reduction reaction (NORR) is a "two birds-one stone" method, which can not only remove NO pollutant, but also produce valuable ammonia (NH). However, a mechanistic understanding of the nitrate reduction process remains very limited. Herein, we highlighted a dissociative-associative mechanism for the NORR, in which the N-O bond of nitrate is initially broken to form *O and *NO intermediate adsorbed on two active sites (dissociation process) and then subsequently hydrogenated and reduced to ammonia (association process). By taking a series of diatomic site catalysts (CuTM/g-CN and CuTM/NC, TM= Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) as models, we systematically investigate the dissociative-associative mechanism for the NORR and compared with the Cu-based single-atom catalysts which follows the traditional directly associative mechanism. Density functional theory (DFT) calculations show that dissociative-associative mechanism is energetically favorable on seven catalysts (CuTi/g-CN, CuV/g-CN, CuMn/g-CN, CuCo/g-CN, CuV/NC, CuCr/NC and CuFe/NC) with the significantly reduced limiting potential of - 0.14 V to - 0.47 V. Specifically, an efficiently screening strategy was proposed to determine the dissociative-associative or directly associative mechanism for NORR. This work can provide useful guideline for the rational design and development of NORR electrocatalysts.
电化学硝酸盐还原反应 (NORR) 的发展是一种“一石二鸟”的方法，不仅可以去除 NO 污染物，还可以生产有价值的氨 (NH)。然而，对硝酸盐还原过程的机理理解仍然非常有限。在此，我们强调了 NORR 的一种解离-缔合机制，其中硝酸盐的 N-O 键最初被打破，形成吸附在两个活性位点上的 *O 和 *NO 中间物（解离过程），然后随后被氢化和还原为氨（缔合过程）。通过采用一系列双原子位催化剂（CuTM/g-CN 和 CuTM/NC，TM=Ti、V、Cr、Mn、Fe、Co、Ni、Cu、Zn）作为模型，我们系统地研究了 NORR 的解离-缔合机制，并与遵循传统直接缔合机制的 Cu 基单原子催化剂进行了比较。密度泛函理论 (DFT) 计算表明，在七种催化剂（CuTi/g-CN、CuV/g-CN、CuMn/g-CN、CuCo/g-CN、CuV/NC、CuCr/NC 和 CuFe/NC）上，解离-缔合机制在能量上是有利的，其极限电位从 -0.14 V 显著降低至 -0.47 V。具体而言，提出了一种有效的筛选策略来确定 NORR 的解离-缔合或直接缔合机制。这项工作可为 NORR 电催化剂的合理设计和开发提供有用的指导。
