Outstanding photocatalytic degradation performance under low light intensity via mitigating the quenching reaction of oxygen-centered organic radicals and oxygen

Abstract

Traditional indiscriminate free radicals pose challenges to photocatalyst stability. To address this issue, oxygen-centered organic radicals (OCORs) anchored on catalyst surfaces were developed recently. However, strategies to alleviate the quenching reaction between OCORs and oxygen are lacking. Herein, the tetrasubstituted carbazole derivative-anthraquinone CZAQ-1, generating OCORs, was fabricated as photocatalyst. CzAQ-1 outperforms reported photocatalysts under low-intensity visible light, achieving 100 % degradation efficiency within 90 minutes at 10 mW·cm−2 and 30 minutes at 100 mW·cm−2. It exhibits exceptional stability over 10 cycles and yields hydrogen peroxide production of 3582 μmol·h−1·g−1 during degradation. The outstanding performance is attributed to OCORs serving as the primary oxidative active species, effectively mitigating quenching reactions with oxygen. This process is accomplished through an innovative strategy of reducing the electrostatic potential of oxygen atoms in OCORs. This study provides insights into OCORs and proposes strategies for optimizing organic polymer structures to enhance photocatalytic performance by inhibiting OCORs-oxygen reactions.