Flue gas to urea: A path of flue gas resourceful utilization through electrocatalysis

Abstract

Flue gas has caused great damage to the environment and human health. At present, the treatment of flue gas requires high operating costs, accompanied by the loss of huge resources. In this regard, we designed a path to use the flue gas rich in NOx, SO2 and CO2 to obtain valuable fertilizer, urea. We demonstrate that HCOOH can be obtained from CO2 reduction by the hydrated electron generated by irradiated SO32−, a product from flue gas SO2 removal, and then urea can be synthesized by electrochemical coupling of HCOOH and NO on a Ag-Cu Janus nanoparticle electrocatalyst. The *NO hydrogenation (*NHO) preferentially occurs on the Ag-Cu Janus interface, promoting the formation of CN bonds. An average urea yield of 8098.5 μg h−1 mg−1 was achieved on Ag-Cu Janus nanoparticles catalyst at − 0.45 V versus the reversible hydrogen electrode (RHE) with a high Faradic efficiency of 55.45 %. Our work provides a feasible way for the resource utilization of flue gas.