Enhancing Oxygen Evolution: Novel Bay-Substituted Perylene Diimide Polymers with Phenol Groups as High-Performance Photocatalysts

Developing an organic photocatalyst with exceptional efficiency in photocatalytic oxygen evolution remains a significant challenge, and the strategic design of the molecular structure is the cornerstone for augmenting the photocatalytic activity to enhance the efficiency. Herein, a bay-substituted perylene diimide polymer (PDI) with phenol as an electron-donating substituent was prepared. The findings indicate a substantial enhancement in visible light absorption and a reduction in the band gap following the introduction of phenol at the bay position of PDI, which is attributed to the push–pull intramolecular charge transfer mechanism. Furthermore, the electron-donating substituent contributed to the tunable energy level since both the VB and CB positions shifted toward positive potentials. Consequently, the phenol-substituted PDI demonstrated an oxygen evolution rate of 2006.53 μmol·g –1 ·h –1, even in the absence of any cocatalysts and under visible light illumination, which is 2.6 times higher than that of PDI. This work demonstrates an efficient strategy to functionalize PDI with electron-donating substituent for improving the photocatalytic O 2 evolution rate.