Abstract:

The pollution of nitrate nitrogen (NO₃^--N) in water has attracted wide attention in the world, which causes the deterioration of water ecological environment and poses a serious threat to human health. In this work, the Ti foam-Ni-Sn/Bi electrode was prepared by electroless Ni and electrodeposition plating Sn/Bi on titanium foam plate. The SEM, XRD and electrochemical tests indicated that Ni and Sn/Bi were successfully deposited on the Ti substrate and intermediate layer Ni, respectively, with a larger electrochemical active area and more active sites. The system of Ti foam-Ni-Sn/Bi electrode as cathode and Ti/RuO₂-Ir₂O₃ electrode as anode was constructed and used for electrocatalytic reduction of the NO₃^--N simulated water. The results indicated the degradation rate of nitrate nitrogen was 87.43% and the N₂ selectivity was 90.73%, as the initial NO₃^--N concentration was 150mg/L, electrocatalytic reduction time was 6h, the current density was 20mA/cm², pH was 3, stirring rate was 600r/min, and the distance between electrodes was 3cm. The Ti foam-Ni-Sn/Bi cathode prepared in this work showed high electroreduction activity and N₂ selectivity in electrocatalytic reduction of the NO₃^--N.

Key words: Ti foam-Ni-Sn/Bi electrode, nitrate nitrogen(NO₃^--N), electroreduction, nitrogen selectivity

摘要：

水体中硝酸盐氮（NO₃^--N）的污染不仅会造成水生态环境的恶化，还对人类健康构成严重威胁，已引起世界广泛关注。本文通过在泡沫钛板（Ti foam）上化学镀Ni-电沉积镀Sn/Bi的方法制备出一种新型含有中间层的Ti foam-Ni-Sn/Bi电极。扫描电子显微镜、X射线衍射仪以及电极性能特性测试结果表明Ni以及Sn/Bi被分别成功沉积到了Ti基底和Ni中间层上，并具备较大的电化学活性面积和较多的活性位点。以制备的Ti foam-Ni-Sn/Bi电极为阴极、Ti/RuO₂-Ir₂O₃电极为阳极构建电还原体系，对水中NO₃^--N进行电还原处理。实验结果表明，在初始NO₃^--N浓度为150mg/L、电流密度为20mA/cm²、pH为3、搅拌速率600r/min、板间距为3cm时，电还原6h后NO₃^--N去除率达87.43%，氮气（N₂）选择性为90.73%。因此，本方法制备的Ti foam-Ni-Sn/Bi电极在NO₃^--N电还原过程中表现出较好的还原性能和较高的N₂选择性。

关键词: Ti foam-Ni-Sn/Bi电极, 硝酸盐氮, 电还原, 氮气选择性