Synergizing Electron and Heat Flows in Photocatalyst for Direct Conversion of Captured CO2

• Published in: Angewandte Chemie International Edition 2023-06, Vol.62 (23), p.e202302152-n/a
• Main Authors: Choi, Chungseok, Zhao, Fengyi, Hart, James L, Gao, Yuanzuo, Menges, Fabian, Rooney, Conor L., Harmon, Nia J., Shang, Bo, Xu, Zihao, Suo, Sa, Sam, Quynh, Cha, Judy J., Lian, Tianquan, Wang, Hailiang
• Format: Article
• Language: English
• Subjects: Blackbody; Cadmium; Cadmium sulfide; Carbamates (tradename); Carbon dioxide; Chemical reduction; Chemistry; CO2 Capture; CO2 Reduction; Cobalt; Direct conversion; Electrons; Heat flow; Heat transfer; Heat transmission; Highways; Molecular Catalyst; Multi wall carbon nanotubes; Nanotechnology; Nanotubes; Photocatalysts; Photochemicals; Photochemistry; Photothermal conversion; Quantum dots; Solar energy; Ternary Hybrid Material
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202302152

We report a ternary hybrid photocatalyst architecture with tailored interfaces that boost the utilization of solar energy for photochemical CO2 reduction by synergizing electron and heat flows in the photocatalyst. The photocatalyst comprises cobalt phthalocyanine (CoPc) molecules assembled on multiwalled carbon nanotubes (CNTs) that are decorated with nearly monodispersed cadmium sulfide quantum dots (CdS QDs). The CdS QDs absorb visible light and generate electron‐hole pairs. The CNTs rapidly transfer the photogenerated electrons from CdS to CoPc. The CoPc molecules then selectively reduce CO2 to CO. The interfacial dynamics and catalytic behavior are clearly revealed by time‐resolved and in situ vibrational spectroscopies. In addition to serving as electron highways, the black body property of the CNT component can create local photothermal heating to activate amine‐captured CO2, namely carbamates, for direct photochemical conversion without additional energy input. A ternary hybrid photocatalyst architecture is developed to convert amine‐captured CO2 to syngas with solar energy. The carbon nanotube plays key roles in transferring photoexcited electrons from the quantum dot to the molecular catalyst and in generating local heat from light irradiation for carbamate activation.