Protruding‐Shaped Co Polarization Field on Ultrathin Covalent Triazine Framework Nanosheets for Efficient CO2 Photoreduction

• Published in: Advanced energy materials 2024-09, Vol.14 (33), p.n/a
• Main Authors: Ma, Zhixue, Yin, Huang, Lyu, Pengbo, Xu, Yuxi
• Format: Article
• Language: English
• Subjects: 2D triazine polymer; Carbon dioxide; charge separation; Chemical synthesis; CO2 photoreduction; Current carriers; Electric fields; Light irradiation; Nanosheets; Orbitals; Photocatalysis; Photocatalysts; Polarization; polarization field; Reaction kinetics; single‐atom photocatalysis
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202401619

Single‐atom photocatalysts (SAPs) engineered on various supports offer a promising pathway to efficiently convert CO2 into high‐valued products. However, most SAPs with near‐planar metal atom coordination structure suffer from low conversion efficiency, mainly due to the weak local polarized electric field which retards the reaction kinetics. Herein, this study reports for the first time a photocatalyst which simultaneously integrates protruding‐shaped Co single atom and strong polarization field in ultrathin crystalline covalent‐triazine‐framework nanosheets (donate as Co1/CTF‐NSs). Both experimental results and theoretical simulations demonstrated that giant local polarization field is successfully triggered on the Co1/CTF‐NSs, which induced directional charge migration and greatly promoted the separation of photogenerated carriers. The protruding‐Co centers enhanced the overlap between CO2 2p and Co 3d orbitals, thereby facilitating a strong affinity for CO2 adsorption. Furthermore, the local polarization fields between the protruding‐Co and CO2 drove the injection of a substantial number of electrons from Co 3d into CO2 π antibonding orbitals, leading to the effective activation and reduction of the CO2 molecules. Consequently, the as‐synthesized Co1/CTF‐NSs exhibited a remarkable CO production rate of 5391 µmol g−1 h−1 and a high selectivity (97.3%) under visible light irradiation, which represents one of the best molecular framework photocatalysts to date. Protruding‐shaped Co single atoms anchored on ultrathin crystalline covalent triazine framework nanosheets with strong polarization field is designed, which significantly promote the adsorption and activation of CO2, reduce the formation energy barrier of key *COOH intermediates and accelerate charge separation and transfer dynamics, leading to the superior CO2 photoreduction activity and selectivity.