Insight into Photocatalytic C─N Coupling for Urea Synthesis on Ru Single Atom Modified CeO2

Abstract Currently, the production of urea by photochemical routes holds significant potential. However, photocatalytic urea synthesis is significantly limited by the co‐sorption and activation of CO 2 , H 2 O, and N 2 as well as C─N coupling process. Herein, Ru 1 (single atom)/CeO 2 ‐V O (containing oxygen vacancies) is synthesized by a room‐temperature photochemical strategy. Benefiting from the synergistic effect of Ce 3+ ‐V O and single atoms, Ru 1 /CeO 2 ‐V O nanosheets delivered the highest urea yield rate of 13.73 µmol g −1 h −1 . Ultrafast transient absorption spectroscopy demonstrated that the localized asymmetric structure formed by oxygen vacancies and Ru single atoms on CeO 2 can generate a stronger locally polarized electric field, thereby extending the photogenerated carrier lifetime. Experimental and theoretical calculations showed that Ru site promoted N 2 adsorption and optimized water dissociation, which ensured the formation of N‐containing intermediates and the supply of protons to synthesize urea. The Ce‐ V O site activated CO 2 to generate *CO, and the formed *CO migrated from the site to the adjacent Ru‐V O site. Further, the synergistic action of the dual sites promotes *CO couples with *NNH to form *NCONH, eventually converting to urea. Accordingly, this work sheds insight into the design of dual sites for effective photocatalytic C─N bond coupling to synthesize urea.