Effective and sustainable electrocatalytic reduction of nitrate is greatly desired to solve the problem of global water contamination and provide a promising way to generate fossil-free ammonia. In this regard, Pt-Fe₃O₄ nanoparticles are decorated on Ni foam (NF) using the hydrothermal method to achieve Pt-Fe₃O₄/NF nanocomposite electrocatalyst. Various characterization techniques investigate the structural and morphological properties of Pt-Fe₃O₄/NF nanocomposite. Benefiting from the small size of Pt and Fe nanoparticles, the Pt-Fe₃O₄/NF nanocomposite reveals excellent performance for electrocatalytic nitrate reduction with an NH₄⁺ yield rate of 0.301 mmol h⁻¹ cm⁻² (5.418 mg h⁻¹ mg⁻¹_cat.) and Faradaic efficiency of 80.7% at − 0.8 V vs. RHE. Pt-Fe₃O₄/NF nanocomposite exhibits unique metallic properties and abundant surface sites due to a synergistic effect of Pt-Fe nanostructure favorable for the electrochemical and hydrogenation reduction processes. Moreover, Pt-Fe₃O₄/NF nanocomposite reveals outstanding long-term stability and durability. Isotope labeling experiments are performed, and results demonstrate that ammonia originates from nitrate reduction. These favorable outcomes of Pt-Fe₃O₄/NF nanocomposite emphasize its potential for treating nitrate wastewater for ammonia recovery and prospects for its industrial applications.

Graphical Abstract

An efficient electrocatalyst was prepared by fabricating Pt-Fe₃O₄ on NF using hydrothermal method for electrochemical nitrate reduction to ammonia. Pt-Fe₃O₄/NF showed a remarkable NH₄⁺ yield rate with high Faradaic efficiency at − 0.8 V vs. RHE. Also, the Pt-Fe₃O₄/NF nanocomposite exhibited outstanding stability and durability.

中文翻译：

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泡沫镍纳米复合材料负载 Pt 改性 Fe3O4 用于电催化硝酸盐还原制氨

迫切需要有效且可持续的电催化还原硝酸盐来解决全球水污染问题，并提供一种有前景的生产无化石氨的方法。在这方面，采用水热法将Pt-Fe ₃ O ₄纳米颗粒修饰在泡沫镍（NF）上，以获得Pt-Fe ₃ O ₄ /NF纳米复合电催化剂。_{各种表征技术研究了 Pt-Fe 3} O ₄ /NF 纳米复合材料的结构和形态特性。受益于Pt和Fe纳米粒子的小尺寸，Pt-Fe ₃ O ₄ /NF纳米复合材料表现出优异的电催化硝酸盐还原性能，NH ₄ ⁺产率为0.301 mmol h ^-1  cm ^-2 (5.418 mg h ^-1  mg ⁻¹ _cat. )，相对于 RHE，在 − 0.8 V 时法拉第效率为 80.7%。由于Pt-Fe纳米结构有利于电化学和氢化还原过程的协同效应，Pt-Fe ₃ O ₄ /NF纳米复合材料表现出独特的金属性能和丰富的表面位点。此外，Pt-Fe ₃ O ₄ /NF纳米复合材料具有出色的长期稳定性和耐久性。进行了同位素标记实验，结果表明氨源自硝酸盐还原。Pt-Fe ₃ O ₄ /NF纳米复合材料的这些有利结果强调了其处理硝酸盐废水以回收氨的潜力及其工业应用前景。

图形概要

采用水热法在NF上制备Pt-Fe ₃ O ₄ ，制备了一种高效电催化剂，用于电化学硝酸盐还原氨。Pt-Fe ₃ O ₄ /NF 在− 0.8 V vs. RHE 下表现出显着的 NH ₄ ⁺产率和高法拉第效率。此外，Pt-Fe ₃ O ₄ /NF纳米复合材料表现出出色的稳定性和耐久性。