Selective conversion of nitrate to nitrogen by CuNi alloys embedded mesoporous carbon with breakpoint chlorination
Selective conversion of nitrate to nitrogen by CuNi alloys embedded mesoporous carbon with breakpoint chlorination
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DOI：
10.1016/j.jwpe.2021.102174
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发表时间：
2021-08
影响因子：
7
通讯作者：
Xinyun Yao;Bei Yu;Xue Yinghao;X. Ran;Jiaqing Zuo;K. Qiu
中科院分区：
文献类型：
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作者：
Xinyun Yao;Bei Yu;Xue Yinghao;X. Ran;Jiaqing Zuo;K. Qiu
硝酸盐是地表水和地下水中常见的污染物，电催化还原为无害的氮气是一种有前途的技术，可以是潜在的能源效率和环境友好的。阻碍其大规模实施的瓶颈主要归因于对最终产物N2的不令人满意的选择性。为了解决这一挑战，本文采用了两步策略，其中NO3−首先在阴极还原为NH 4+，然后通过阳极断点氯化产生的ClO−快速非电化学氧化为N2。注意，ClO−的形成可以通过Cl−离子的剂量容易地控制和增强，上述过程的总体硝酸盐去除效率由其NO3−至NH 4+的活性决定。因此，合理设计了高性能的铜镍合金嵌入介孔碳电催化剂，其在没有Cl-的情况下表现出完全的NO3-转化率，并且在添加Cl-的情况下表现出100%的N2选择性。通过密度泛函理论计算，证实了Ni原子的引入显著增强了 *NHOH和 * NH 2 OH中间体的吸附，降低了 *NOH加氢生成 *NH3（NH 4+）的势垒.此外，含氮有序介孔碳载体不仅有利于合成均匀分布的CuNi纳米颗粒（约。20 nm），而且还确保了足够的质量和电荷转移，以及高耐久性。
The electrocatalytic reduction of nitrate, a common contaminant in surface and ground water, to the harmless nitrogen gas is a promising technology that can be potentially energy efficient and environmentally friendly. The bottleneck hindering its large-scale implementation is mainly attributed to the unsatisfactory selectivity toward the final product N2. To solve this challenge, a two-step strategy was applied here, in which the NO3−was first reduced to NH4+at the cathode, followed with a rapid non-electrochemical oxidation to N2by the ClO−generated from anodic breakpoint chlorination. Note that the formation of ClO−may be easily controlled and enhanced by the dosage of Cl−ions, the overall nitrate removal efficiency for the above process was determined by its NO3−to NH4+activity. The high-performance copper-nickel alloys embedded mesoporous carbon electrocatalysts were therefore rationally designed, which exhibited a complete conversion of NO3−in the absence of Cl−, and furthermore, a 100% N2selectivity with the addition of Cl−. Using density functional theory calculations, it was verified that the incorporation of Ni atoms into Cu interface significantly enhanced the adsorption of *NHOH and *NH2OH intermediates, lowering the barrier of *NOH hydrogenation to *NH3(NH4+). Besides, the nitrogen-containing ordered mesoporous carbon support not only facilitated the synthesis of uniformly distributed CuNi nanoparticles (ca. 20 nm), but also ensured the sufficient mass and charge transfer, as well as the high durability.