Near-Infrared Light Catalysis of Carbon Dioxide Reduction by Conjugated Porous Aromatic Frameworks.

Current CO2 photocatalytic systems mainly work in ultraviolet (UV) and visible (Vis) light regions, and the inability to utilize the abundant near-infrared (NIR) radiation or the low utilization rate is still a bottleneck for practical applications. We address this challenge through the strategic synthesis of metal-free conjugated porous aromatic frameworks (PAFs), PAF-332-DCM, to enhance the NIR absorption capabilities, achieving a CO production rate of ~74.7 µmol g-1 h-1 in gas-solid phase CO2 reduction, surpassing typical NIR-responsive catalysts. Meanwhile, PAF-332-DCM can obtain a CO production rate of 344.1 µmol g-1 h-1 in full-spectrum irradiated CO2 reduction. Infrared thermography reveals that the non-radiative attenuation of PAF-332-DCM leads to high photothermal temperature under NIR irradiation, which accounts for its reduction performance. Mechanistic studies combining fs-TA spectroscopy and in situ infrared characterization elucidate the photocatalytic pathway and intermediate formation. This result indicates that PAF-332-DCM can be a promising metal-free catalyst for practical solar-driven CO2 conversion.