Reveal the role of inert groups in donor-acceptor conjugated polymer for two opposite photocatalytic reactions

Oxidation and reduction reactions are two distinct reactions, and the efficient driving of these two reactions through a photocatalyst is of great significance in the field of catalysis. In this work, donor-acceptor conjugated polymers with different inert groups were designed and synthesized using cyclotriphosphazene as the electron donor (D) and s-triazine ring as the electron acceptor (A), respectively. The result showed that the introduction of methyl groups preserved the D-A structure in the conjugated polymer (Me-COP). The migration ability of photogenerated carriers and the adsorption of reactant sequences in Me-COP sample were significantly optimized due to their own hyperconjugation and steric hindrance. Under visible light irradiation, Me-COP exhibited good selective reduction activity of CO2 to CH4. Me-COP for thioether oxidation to sulfoxide also showed excellent selective photocatalytic activity. This study underlines the significance of adding inert groups to the conjugated polymers in order to create multifunctional photocatalysts.