以鈀銅奈米團簇配合電化學方法選擇性還原生成氨氮與氮氣之研究

Abstract

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This study investigated Cu monometallic and PdCu bimetallic electrodes prepared on Ni foam with varying plating times for the reduction of nitrate. SEM images revealed the morphology evolution, with Cu/Ni electrodes exhibiting agglomerated granules transforming into rhombus structures as plating time increased. Increasing plating time led to a higher Cu proportion, an increased Cu(200)/Cu(111) ratio, and larger crystallite sizes for Cu(111) and Cu(200). PdCu/Ni showed a grape-cluster-like surface with accumulated palladium particles on the surface of copper. Electrochemical impedance spectroscopy indicated the improved electron transfer for the Cu/Ni electrodes and the additional plating of Pd showed an even better electron transfer. The double-layer capacitance (Cdl) revealed that the surface area activity increased with extended plating time for Cu from 2.6 to 5.5mF/cm^2. Nitrate reduction experiments on Cu monometallic electrode demonstrated high removal efficiency and achieving 100% nitrate removal at 210 minutes, with NH_4^+ as the main product. Bimetallic electrode; PdCu10min/Ni exhibited enhanced activity than Cu monometallic electrode. Under constant potential, NO_3^- was fully converted to NH_4^+ without N_2 generation in acidic condition. PdCu bimetallic electrode showed consistent performance over multiple cycles but no N_2 was generated. Electrochlorination with the addition of Cl^- enhanced nitrogen gas evolution and resulted in a low ammonia residual.