The Electrochemical reduction of nitrate to ammonia (NH₃) is a process of great significance to energy utilization and environmental protection. However, it suffers from sluggish multielectron/proton-involved steps involving coupling reactions between different reaction intermediates and active hydrogen species (H_ads) produced by water decomposition. In this study, a Ru-doped NiFe-MIL-53 (NiFeRu-MIL-53) supported on Ni foam (NF) has been designed for the nitrate reduction reaction (NO₃RR). The NiFeRu-MIL-53 exhibits excellent NO₃RR activity with a maximum Faradaic efficiency (FE) of 100% at −0.4 V vs. RHE for NH₃ and a maximum NH₃ yield of 62.39 mg h^–1 cm^–2 at −0.7 V vs. RHE in alkaline media. This excellent performance for the NO₃RR is attributed to a strong synergistic effect between Ru and reconstructed NiFe(OH)₂. Additionally, the doped Ru facilitates water dissociation, leading to an appropriate supply of H_ads required for N species hydrogenation during NO₃RR, thereby further enhancing its performance. Furthermore, in situ Raman analysis reveals that incorporating Ru facilitates the reconstruction of MOFs and promotes the formation of hydroxide active species during the NO₃RR process. This work provides a valuable strategy for designing electrocatalysts to improve the efficiency of the reduction of electrochemical nitrate to ammonia.

中文翻译：

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掺钌 NiFe-MIL-53 具有促进重建和活性氢补充，可增强硝酸盐还原


硝酸盐电化学还原为氨(NH ₃ )是一个对能源利用和环境保护具有重要意义的过程。然而，它的多电子/质子参与步骤缓慢，涉及不同反应中间体和水分解产生的活性氢物种（H _ads ）之间的偶联反应。在这项研究中，设计了一种负载在泡沫镍 (NF) 上的掺钌 NiFe-MIL-53 (NiFeRu-MIL-53)，用于硝酸盐还原反应 (NO ₃ RR)。 NiFeRu-MIL-53 表现出优异的 NO ₃ RR 活性，相对于 NH ₃ 的 RHE，在 -0.4 V 时最大法拉第效率 (FE) 为 100%，最大 NH < b5> 产量为 62.39 mg h ^–1 cm ^–2 ，在碱性介质中，相对于 RHE，-0.7 V。 NO ₃ RR 的优异性能归因于 Ru 和重构 NiFe(OH) ₂ 之间强大的协同效应。此外，掺杂的Ru有利于水的解离，从而在NO ₃ RR过程中提供适当的N物种氢化所需的H _ads ，从而进一步增强其性能。此外，原位拉曼分析表明，掺入Ru有利于MOF的重构，并促进NO ₃ RR过程中氢氧化物活性物质的形成。这项工作为设计电催化剂以提高电化学硝酸盐还原为氨的效率提供了有价值的策略。