Hydrogenation of carbon dioxide under atmospheric pressure and low temperature

In order to realize the effective reduction and utilization of carbon dioxide (CO2) in coal-fired flue gas, a process was developed under atmospheric pressure that uses KBH4 as an efficient hydrogen donor. By investigating the influencing factors of CO2 conversion, the optimal experimental conditions were determined and the average CO2 conversion efficiency of 50.36% was obtained when the KBH4 concentration was 0.2 mol/L, reaction temperature was 50 °C, solution pH was 8, and flow rate was 300 mL/min. The experimental results also verified that the coexisting gases such as sulfur dioxide (SO2), nitric oxide (NO) and oxygen (O2) in flue gas had no significant competition or inhibition effect on CO2 conversion. Meanwhile, the conversion products were analyzed by an Ion Chromatography (IC) and Fourier Transform Infrared Spectroscopy (FT-IR), and the results proved that the main reaction product was formate. Combined with the relevant literatures, the mechanism of CO2 reaction with KBH4 was proposed.