Covalent Organic Framework Confining Pd Nanocluster Enhances Oxygen Adsorption for Boosting Photosynthesis of Hydrogen Peroxide

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High Resolution Image Download MS PowerPoint Slide A covalent organic framework (COF) is regarded as a promising molecular platform for photocatalytic hydrogen peroxide (H 2 O 2 ) production; however, it is still limited by weak O 2 adsorption over nonmetallic active sites. Herein, we reported a nano confinement strategy of integrating Pd nanoclusters (NCs) into a COF nanocavity for enhancing the adsorption of O 2 to boost the photosynthesis of H 2 O 2 . We demonstrate that Pd NCs can significantly increase the adsorption capacity and intensity of O 2 on Py-TPA COFs@Pd NCs (Py, 1,3,6,8-tetrakis(4-aminophenyl)pyrene; TPA, terephthalaldehyde), greatly enhancing photocatalytic H 2 O 2 formation kinetics from 0.797 × 10 –3 mmol L –1 h –1 to 2.47 × 10 –3 mmol L –1 h –1 . The as-made Py-TPA COFs@Pd NCs exhibit a high mass activity of 2614.0 μmol g –1 h –1 for the photosynthesis of H 2 O 2, 3-fold higher than that of pure Py-TPA COFs (858.0 μmol g –1 h –1 ). The concentration of H 2 O 2 solution in the flow cell photocatalytic device can reach 7.35 mmol L –1 after a 10 h cycle, which can realize 100% antibacterial performance. Mechanism studies reveal that strong adsorption interaction between O 2 and Py-TPA COFs@Pd NCs promotes the orbital coupling between 4d orbitals of Pd NCs and 2p orbitals of O 2 molecules for enhancing the injection of photogenerated electrons into π* orbitals of O 2, thus accelerating the formation kinetics of H 2 O 2 .