Spatially confined iron single-atom and potassium ion in carbon nitride toward efficient CO2 reduction

• Published in: Applied catalysis. B, Environmental Environmental, 2022-11, Vol.316, p.121643, Article 121643
• Main Authors: Cheng, Xiang, Wang, Junmin, Zhao, Kang, Bi, Yingpu
• Format: Article
• Language: English
• Subjects: Carbon nitride; CO2 reduction; Photocatalysis; Single atom; Spatial confinement
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2022.121643

Artificial photosynthesis is a promising strategy for converting CO2 and H2O into fuels and value-added products, while the low catalytic efficiency greatly restricts its practical applications. Herein, we demonstrated that graphitic carbon nitride with spatially confined Fe single-atom and potassium ion (FeN4/K-g-C3N4) exhibited the high activity and selectivity for photocatalytic CO2 reduction. Specifically, the conversion rates of CO2 into CO could achieve up to 20.00 μmol g−1 h−1 with nearly 100% selectivity, more than 10 times higher performances than pristine g-C3N4. Comprehensive characterizations and theoretical calculations revealed that the single-atom Fe bonded with four N atoms in g-C3N4 intralayer, which serve as the active center for absorption and activation of CO2 molecules. The alkali K ions inserted the g-C3N4 interlayers owing to their suitable diameters, which could effectively promote charge separation and transfer. Synergizing the spatial confinements of Fe single-atoms and K ions in g-C3N4 remarkably promoted the photocatalytic activity and selectivity for CO2 reduction into CO. [Display omitted] •One-step molten-salt-assisted route was developed for fabricating dual-spatially confined Fe single-atom and K+ ion in C3N4.•The single-atom Fe acted as active center for significantly promoting CO2 absorption and conversion.•The intercalated K ions remarkably promoted charge transfer between adjacent layers in C3N4.•The photocatalytic CO2 reduction activity and selectivity have been significantly enhanced.