Energy consumption and long-term stability of a cathode are two important aspects of great concern in electrocatalytic nitrate reduction. This work studied a binderless FeNi/graphitized mesoporous carbon directly formed on Ni Foam (FeNi/g-mesoC/NF, 7.3 wt % of Fe) and evaluated its electrocatalytic nitrate reduction performance. We proposed a unique structure model of FeNi/g-mesoC/NF cathode in which FeNi alloy nanoparticles were uniformly embedded in mesoporous carbon and graphitized carbon shells were coated on isolated alloy nanoparticles. Oxygen vacancies (OVs) in FeNi oxide passivating layer facilitate the conversion of NO₃^–-N anions on cathode. Toxic NO₂^–-N was almost undetected due to the synergetic effects of FeNi electrocatalysis, and the NO₃^–-N conversion was high in comparation with ever reported iron-based cathode. The NO₃^–-N conversion showed ultrahigh electrocatalytic stability during one-month-recycling test while the physiochemical properties showed negligible change for FeNi/g-mesoC/NF except the increase of OVs. The energy consumption to treat simulated underground water (50% of NO₃^–-N conversion) was low (0.7 kWh mol^–1) for 50 mg L^–1 NO₃^–-N. This binderless composite cathode shows great potential in electrocatalytic NO₃^–-N removal in underground water.

中文翻译：

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富FeNi /石墨化介孔碳/ Ni泡沫的无粘结剂和氧空位，可用于硝酸盐的电催化还原

阴极的能量消耗和长期稳定性是电催化硝酸盐还原中极为关注的两个重要方面。这项工作研究了直接在镍泡沫上形成的无粘结剂FeNi /石墨化的介孔碳（FeNi / g-mesoC / NF，7.3重量％的Fe），并评估了其电催化硝酸盐还原性能。我们提出了一种独特的FeNi / g-mesoC / NF阴极结构模型，其中FeNi合金纳米颗粒均匀地嵌入中孔碳中，而石墨化的碳壳被包覆在分离的合金纳米颗粒上。FeNi氧化物钝化层中的氧空位（OVs）促进了阴极上NO ₃ ^-- N阴离子的转化。由于FeNi电催化和NO的协同作用，几乎没有检测到有毒的NO ₂ ^-- N与以前报道的铁基阴极相比，₃ ^- N转化率很高。在一个月的循环测试中，NO ₃ ^-- N的转化显示出超高的电催化稳定性，而FeOV / g-mesoC / NF的理化性质变化可忽略不计，除了OVs的增加。对于50 mg L ^–1 NO ₃ ^– -N ，处理模拟地下水（NO ₃ ^– -N转化的50％）的能耗很低（0.7 kWh mol ^–1）。这种无粘合剂的复合阴极在地下水中电催化去除NO ₃ ^-- N方面显示出巨大潜力。