To mitigate global warming, many researchers are making efforts to reduce CO2 emissions. In this context, urea synthesis offers a useful approach for CO2 conversion since it utilizes both CO2 and NOx generated as byproducts of internal combustion engines. Electrocatalytic urea synthesis represents a promising and sustainable alternative to the energy-intensive Bosch–Meiser process, which operates under harsh conditions (100-300 bar, above 400℃). SrFeO3 (SF) has shown potential in various fields, including electrocatalysis, such as the oxygen evolution reaction. However, structural deformation induced by CO2 exposure reduces its catalytic activity, thereby limiting its applicability in urea synthesis. Fluorine doping into the perovskite structure enhances the structural stability of the cubic perovskite framework and improves CO2 tolerance due to the higher electronegativity of fluorine compared to oxygen. Furthermore, A-site vacancy modulates the electronic structure and enhances catalytic activity. In this regard, to overcome the decrease in catalytic activity caused by CO2-induced structural deformation, we doped fluorine into SF (SFF) and introduced an A-site cation vacancy (Sr) into SFF (A-SFF) as a strategy to enhance structural stability and catalytic activity. Our density functional theory (DFT) calculations revealed that A-SFF exhibited a more favorable reaction energy profile for urea synthesis compared to SFF. Furthermore, A-SFF exhibited favorable selectivity for urea synthesis by suppressing competing reactions, including the nitrate reduction reaction and the hydrogen evolution reaction. To explore the origin of the enhanced catalytic activity, we conducted analyses of the density of states and charge density difference. The results revealed that the Sr vacancy modulates the d-band center and charge transfer, thereby optimizing interactions between reaction intermediates and the catalytic surface for urea synthesis. Based on these findings, this study offers insights for enhancing the electrocatalytic applicability of SF and other metal oxide-based electrocatalysts.
