催化学报

催化学报 ›› 2027, Vol. 92: 365-375.DOI: 10.1016/S1872-2067(26)65241-2

• 论文 • 上一篇    下一篇

次磷酸根界面改性Co(OH)2/Cu纳米线实现2.8 A·cm‒2高电流密度下硝酸盐还原制氨

周瑞晗a, 夏缇萱a, 杨迎晨a, 徐东波a,b,*, 施伟东a,c,*   

  1. a江苏大学化学化工学院, 江苏镇江 212013;
    b南京工程学院江苏省先进结构材料及应用技术重点实验室, 江苏南京 211167;
    c江苏科技大学环境与化学工程学院, 江苏镇江 212100
  • 收稿日期:2026-02-28 接受日期:2026-05-15 出版日期:2027-01-18 发布日期:2026-10-30
  • 通讯作者: *电子信箱: xudb39@ujs.edu.cn (徐东波), swd1978@ujs.edu.cn (施伟东).
  • 基金资助:
    国家自然科学基金(22225808, U24A20551); 江苏省自然科学基金(BK20230551); 江苏省先进结构材料与应用技术重点实验室开放项目(ASMA202503).

Co(OH)2/Cu NWs with interface modification of hypophosphite ions for sustainable ammonia synthesis from nitrate at ~2.8 A·cm-2

Ruihan Zhoua, Tixuan Xiaa, Yingchen Yanga, Dongbo Xua,b,*, Weidong Shia,c,*   

  1. aSchool of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China;
    bJiangsu Key Laboratory of Advanced Structural Materials and Application Technology, Nanjing Institute of Technology, Nanjing 211167, Jiangsu, China;
    cSchool of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212100, Jiangsu, China
  • Received:2026-02-28 Accepted:2026-05-15 Online:2027-01-18 Published:2026-10-30
  • Contact: *E-mail: xudb39@ujs.edu.cn (D. Xu), swd1978@ujs.edu.cn (W. Shi).
  • Supported by:
    National Natural Science Foundation of China (22225808, U24A20551), the Natural Science Foundation of Jiangsu Province (BK20230551), and the Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology (ASMA202503).

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摘要： 近年来, 电化学硝酸盐还原(NO3RR)被视为实现绿色可持续合成氨的一种有效手段. 然而, NO3RR涉及复杂的多电子转移与质子化过程, 缓慢的反应动力学限制了氨的产率和电流密度, 复杂的反应路径也对产物的选择性构成了挑战. 尤其是在大电流密度条件下, 析氢(HER)竞争反应以及含氮中间副产物的生成造成了法拉第效率(FE)的下降. 为了满足规模化工业生产的需要, 设计能够在高电流密度条件下维持高FE的硝酸盐到氨转化的电催化剂至关重要. 当前针对NO3RR电催化剂的研究不断取得新的突破, 但是实现高产率与大电流密度大多依赖提高硝酸盐浓度, 考虑到硝酸盐本身的经济价值远远高于氨, 现实情况下不可能直接使用硝酸盐作为合成氨的原料, 自然水体与污水中的硝酸盐浓度很低, 通过富集浓缩得到高浓度硝酸盐溶液的成本极大, 电催化剂在有限硝酸盐浓度下的性能更具有实际意义.
本文通过电化学沉积的方法结合催化剂的原位重构, 在Cu纳米线(Cu NWs)基底上负载了次磷酸根修饰的氢氧化钴纳米片(P-Co(OH)2), 构建了P-Co(OH)2/Cu NWs串联催化剂, 硝酸根先在铜表面快速转化为亚硝酸根, 随后亚硝酸根在P-Co(OH)2表面进一步脱氧和质子化生成氨, 催化剂在浓度为0.1 mol·L−1的硝酸盐溶液中在−0.7 V vs. RHE的工作电位下实现了96.8%的法拉第效率, 在−1 V vs. RHE的工作电位下, 达到了204.3 mg·h−1·cm−2的高氨产率, 法拉第效率仍能维持在93.4%, 远远超过Cu NWs基底, 并且能够在2.8 A·cm−2平均电流密度下稳定运行20个循环(每个循环1 h)后性能没有衰减. X射线光电子能谱和红外光谱证实了次磷酸根的存在. DMPO-H自旋捕获测试表明, 次磷酸根加速了水的解离产生活性氢自由基, 并且作用于NO3RR过程. 原位红外光谱结果表明, P-Co(OH)2/Cu NWs有更强的脱氧和加氢活性. 循环伏安法测试与原位拉曼光谱结果表明, 次磷酸根有利于诱导生成和保持金属态钴活性相. 通过密度泛函理论计算发现, 在NO3RR过程中原位生成的Co0调节反应中间体吸附, 优化反应路径, 降低了电位决定步骤*NO到*NOH的反应能垒, 对*H的强吸附还避免了过度的HER竞争反应. 通过对比金属Co与Co(OH)2中表面钴原子态密度差异发现, 金属Co中Co原子的d带中心靠近体系的费米能级, 从而调节了NO3RR的中间体吸附与电子转移过程.
综上, 本工作通过简单的电化学沉积制备了P-Co(OH)2/Cu NWs串联催化剂, 该催化剂在有限硝酸盐浓度下展现出卓越的NO3RR性能, 其在大电流密度工况下的稳定性也得到验证, 并且通过原位的测试和理论计算揭示了次磷酸根的作用机制, 为设计高性能NO3RR电催化剂提供了新的思路.

关键词: 硝酸盐还原, 工业电流密度, 次磷酸根, 氨, 界面修饰

Abstract: Ammonia production via nitrate electroreduction (NO₃RR) offers an environmentally benign alternative, yet it is still extremely difficult to simultaneously attain superior Faradaic efficiency and long-lasting durability when operating at the high current densities. Herein, we report a self-supporting electrode comprising Cu nanowires uniformly coated with cobalt hydroxide incorporating surface-coordinated hypophosphite ions (H2PO2−) (denoted as P-Co(OH)₂/Cu NWs), directly fabricated on Cu foam. The P-Co(OH)₂/Cu NWs catalyst exhibited remarkable NO₃RR performance in 0.1 mol·L–1 NaNO3/1 mol·L–1 NaOH, producing NH3 at a rate of 204.3 mg·h–1·cm–2 (−1.0 V) with a peak Faradaic efficiency of 96.8% (−0.7 V), both potentials referenced to RHE. Notably, the electrode maintains stable electroactivity and NH3 selectivity over 20 consecutive test cycles (1 h per cycle) under approximately 2.8 A·cm–2. In-situ attenuated total reflection Fourier transform infrared spectroscopy reveals that the P-Co(OH)₂/Cu NWs electrode promotes enhanced deoxygenation of *NO3 and deep hydrogenation of *NOx intermediates. Cyclic voltammetry test and In-situ Raman spectroscopy demonstrate that the incorporated H2PO2− induce and stabilize the in-situ formation of metallic Co0 phase under operative electrolysis conditions. Density functional theory calculations further elucidate that the metallic Co0 phase, generated in situ during NO3RR, optimizes the adsorption energetics of *NOH, thereby substantially facilitating the energy-demanding step (*NO → *NOH) relative to Co(OH)2, while concurrently strengthening *H adsorption. This work presents a viable electrode design strategy for securing efficient and stable electrocatalytic NO3−-to-NH3 conversion under high-rate operation.

Key words: Nitrate reduction, Industrial current density, Hypophosphite ion, Ammonia, Interface modification