Polyarene Oxides with Tunable Quinone Units for Photocatalytic CO₂ Reduction: A Simple Strategy toward Effective and Selective Catalysts

The photocatalytic transformation of carbon dioxide (CO₂) into valuable chemicals is a challenging process that requires effective and selective catalysts. However, most polymer-based photocatalysts with electron donor−acceptor (D−A) structures are synthesized with a fixed D−A ratio by using expensive monomers. Herein, we report a simple strategy to prepare polyarene oxides (PAOs) with quinone structural units via oxidation treatment of polyarene (PA). The resultant PAOs show tunable D−A structures and electronic band positions depending on the degree of oxidation, which can catalyze the photoreduction of CO₂ with water under visible light irradiation, generating CO as the sole carbonaceous product without H₂ generation. Especially, the PAO with an oxygen content of 17.6% afforded the highest CO production rate of 161.9 μmol g⁻¹ h⁻¹. It is verified that the redox transformation between quinone and phenolic hydroxyl in PAOs achieves CO₂ photoreduction coupled with water oxidation. This study provides a facile way to access conjugated polymers with a tunable D−A structure and demonstrates that the resultant PAOs are promising photocatalysts for CO₂ reduction.