School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, Gardens Point Campus, Brisbane, QLD 4001, Australia.
Phys Chem Chem Phys. 2019 Jan 21;21(3):1546-1551. doi: 10.1039/c8cp06978f. Epub 2019 Jan 8.
Electrochemical reduction of dinitrogen molecules (N) to value-added ammonia by using renewable electricity under mild conditions is regarded as a sustainable and promising strategy for N fixation. However, the lack of efficient, robust and inexpensive electrocatalysts for such electrochemical reduction has prevented its wide application. Herein, we report a novel single-atom catalyst, i.e., a single tungsten (W) atom anchored on N-doped graphyne (W@N-doped graphyne) as a highly efficient and low-cost electrocatalyst for the N reduction reaction. The inert N[triple bond, length as m-dash]N triple bond can be sufficiently activated when an N molecule is adsorbed on the W atom. A single atom of W coordinated with one N atom (doping into an sp-hybridized carbon atom) exhibits the highest catalytic performance with ultra-low onset potential of 0.29 V for N reduction reactions. The 'distal mechanism' is identified as the most favourable catalytic pathway. Moreover, the improved electrical conductivity of W@N-doped graphyne compared to that of pristine graphyne can ensure better electron transfer efficiency during the reduction processes. Our study provides a novel electrocatalyst with excellent catalytic performance for electrochemical reduction of N to NH under ambient conditions.
电化学还原氮气分子（N）为增值氨，利用可再生电力在温和条件下进行，被认为是一种可持续且有前途的固氮策略。然而，缺乏高效、稳健和廉价的电催化剂来进行这种电化学还原，阻碍了其广泛应用。在此，我们报告了一种新型的单原子催化剂，即单钨（W）原子锚定在氮掺杂石墨炔（W@N-掺杂石墨炔）上，作为一种高效且低成本的电催化剂，用于氮气还原反应。当氮气分子吸附在 W 原子上时，惰性的 N≡N 三键可以被充分激活。一个 W 原子与一个 N 原子配位（掺杂到 sp 杂化的碳原子中）表现出最高的催化性能，氮气还原反应的起始电位超低，仅为 0.29V。确定了“远端机制”是最有利的催化途径。此外，与原始石墨炔相比，W@N-掺杂石墨炔的电导率得到了提高，这可以确保在还原过程中更好的电子转移效率。我们的研究为在环境条件下电化学还原 N 为 NH 提供了一种具有优异催化性能的新型电催化剂。
