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.