1,3,5-Triphenylbenzene Based Porous Conjugated Polymers for Highly Efficient Photoreduction of Low-Concentration CO₂ in the Gas-Phase System

Herein, three 1,3,5-triphenylbenzene based porous conjugated polymers (PCPs) are designed for photochemical reduction of CO₂ in simulated flue gas in the mild gas−solid reaction system. By tuning the nature of the comonomers, the PCPs present high surface areas, high CO₂/N₂ selectivity, and broad visible light absorptions with bandgaps of 1.81−2.07 eV. At 1 bar and 273 K, the CO₂ uptake capacity of PCPs is enhanced from 1.28 to 2.18 mmol g⁻¹, with an increase in CO₂ adsorption heat from 21.8 to 28.3 KJ mol⁻¹. In the presence of gaseous water, SO-TPB demonstrates the highest CO production rate of 40.12 μmol h⁻¹ g⁻¹ and nearly 100% product selectivity without using organic sacrificial reagent and additional cocatalyst (>420 nm). Moreover, SO-TPB can be recovered while well retaining the photocatalytic activity and reused at least five runs, indicating good recyclability.