关键词:

电化学还原, NO₂^-, CO₂, 尿素, 925银电极

Abstract:

The electrochemical synthesis of urea by simultaneous reduction of nitrite and CO₂ was performed in 0.02 mol·L^-1 NaNO₂ and 0.2 mol·L^-1 NaHCO₃ aqueous solutions at 925 Ag electrode in laboratory-scale experiments.The effect of several parameters, including electrolysis potential, temperature, and CO₂ pressure, on urea formation was investigated.At the temperature of 293 K,CO₂ pressure of 0.7 MPa, the electrolytic potential of -0.6 V, the current efficiency of urea formation reached 37%.Under the conditions of temperature of 273 K and electrolytic potential of -1.7 V, the current efficiency reached 26% under normal ambient pressure.Based on the relationship of current efficiency and formation of CO, NH₃ and urea, a tentative reaction pathway was proposed.

Key words:

电化学还原, NO₂^-, CO₂, 尿素, 925银电极